U.S. patent application number 15/810587 was filed with the patent office on 2018-03-22 for method of detecting elevator tab failure.
The applicant listed for this patent is UNITED AIRLINES, INC.. Invention is credited to Paul Bowman, Ryan Nurnberger.
Application Number | 20180082499 15/810587 |
Document ID | / |
Family ID | 60038368 |
Filed Date | 2018-03-22 |
United States Patent
Application |
20180082499 |
Kind Code |
A1 |
Bowman; Paul ; et
al. |
March 22, 2018 |
METHOD OF DETECTING ELEVATOR TAB FAILURE
Abstract
A method is provided for verifying proper operation of a left
elevator tab disposed at an end portion of a left elevator of an
aircraft and a right elevator tab disposed at an end portion of a
right elevator of the aircraft. Because proper operation of the
elevator tabs cannot be directly verified by existing aircraft
instrument, the operation of the elevator tabs can be indirectly
verified by analyzing flight data of the aircraft. After
identification of a verification event, in which the elevator tabs
move relative to the elevators, the positions of the left elevator
and right elevator can be measured, and differences in the
positions of the left elevator and right elevator can indicate
proper operation of the left and right elevator tabs.
Inventors: |
Bowman; Paul; (Kingwood,
TX) ; Nurnberger; Ryan; (Chicago, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UNITED AIRLINES, INC. |
Chicago |
IL |
US |
|
|
Family ID: |
60038368 |
Appl. No.: |
15/810587 |
Filed: |
November 13, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15099547 |
Apr 14, 2016 |
9824513 |
|
|
15810587 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B64D 45/0005 20130101;
B64C 9/10 20130101; G07C 5/0816 20130101; B64C 13/42 20130101; B64D
45/00 20130101; B64C 9/12 20130101 |
International
Class: |
G07C 5/08 20060101
G07C005/08; B64C 13/40 20060101 B64C013/40 |
Claims
1. A method of verification of proper operation of a first elevator
tab disposed at an end portion of a first elevator of an aircraft
and a second elevator tab disposed at an end portion of a second
elevator of the aircraft, the method comprising: determine the
occurrence of a verification event that includes movement of the
first elevator tab relative to the first elevator and the second
elevator tab relative to the second elevator, wherein the
verification event occurs at a start time, wherein the first
elevator is at an initial rotational position and the second
elevator is at an initial rotational position at the start time;
determine a first rotational position of the first elevator at a
first time and a first rotational position of the second elevator
at the first time, the first time occurring after the start time;
compare the first rotational position of the first elevator at the
first time to the first rotational position of the second elevator
at the first time; if the first rotational position of the first
elevator at the first time is not different than the first
rotational position of the second elevator at the first time by at
least a first value or by a first range, issue a first alert
associated with the first elevator tab; determine a second
rotational position of the first elevator at a second time and a
second rotational position of the second elevator at the second
time, the second time occurring after the first time and the
difference between the start time and the second time being equal
to an intentional delay between functionality of the first elevator
tab and the second elevator tab; compare the second rotational
position of the first elevator at the second time to the second
rotational position of the second elevator at the elevator at the
second time; if the second rotational position of the second
elevator at the second time is not within a second range of the
second rotational position of the first elevator at the second
time, issue a second alert associated with the second elevator tab;
and if (a) the second rotational position of the first elevator at
the second time is within a third range of the initial rotational
position of the first elevator at the start time and (b) the second
rotational position of the second elevator at the second time is
within the third range of the initial rotational position of the
second elevator at the start time, issue a third alert associated
with both the first elevator tab and the second elevator tab.
2. The method of claim 1, wherein the first elevator is a left
elevator and the first elevator tab is a left elevator tab, and the
second elevator is a right elevator and the second elevator tab is
a right elevator tab.
3. The method of claim 1, wherein the intentional delay is between
6 and 20 seconds.
4. The method of claim 3, wherein the intentional delay is between
8 and 14 seconds.
5. The method of claim 1, wherein the verification event is moving
the aircraft's flap handle out of an "up" detent.
6. The method of claim 1, wherein the verification event is a
detection of a failure of one or both of the primary and secondary
hydraulic systems of the aircraft.
7. The method of claim 1, wherein the first range is between about
0.5.degree. and about 3.0.degree..
8. The method of claim 1, wherein the second range is between about
0.0.degree. and about 0.4.degree..
9. The method of claim 1, wherein the third range is between about
0.0.degree. and about 0.4.degree..
10. A system to analyze flight data to verify proper operation of a
first elevator tab disposed at an end portion of a first elevator
of an aircraft and a second elevator tab disposed at an end portion
of a second elevator of the aircraft, the system comprising a
computing device including a memory and a processor, the memory
adapted to store non-transitory computer executable instructions,
wherein the non-transitory computer executable instructions, when
executed by the processor, cause the system to: analyze the flight
data to determine the occurrence of a verification event that
includes movement of the first elevator tab relative to the first
elevator and the second elevator tab relative to the second
elevator, wherein the verification event occurs at a start time,
wherein the first elevator is at an initial rotational position and
the second elevator is at an initial rotational position at the
start time; analyze the flight data to determine a first rotational
position of the first elevator at a first time and a first
rotational position of the second elevator at the first time, the
first time occurring after the start time; compare the first
rotational position of the first elevator at the first time to the
first rotational position of the second elevator at the first time;
wherein if the first rotational position of the first elevator at
the first time is not different than the first rotational position
of the second elevator at the first time by at least a first value
or by a first range, issue a first alert associated with the first
elevator tab; analyze the flight date to determine a second
rotational position of the first elevator at a second time and a
second rotational position of the second elevator at the second
time, the second time occurring after the first time and the
difference between the start time and the second time being equal
to an intentional delay between functionality of the first elevator
tab and the second elevator tab; compare the second rotational
position of the first elevator at the second time to the second
rotational position of the second elevator at the elevator at the
second time; wherein if the second rotational position of the
second elevator at the second time is not within a second range of
the second rotational position of the first elevator at the second
time, issue a second alert associated with the second elevator tab;
and wherein if (a) the second rotational position of the first
elevator at the second time is within a third range of the initial
rotational position of the first elevator at the start time and (b)
the second rotational position of the second elevator at the second
time is within the third range of the initial rotational position
of the second elevator at the start time, issue a third alert
associated with both the first elevator tab and the second elevator
tab.
11. The system of claim 10, wherein the first elevator is a left
elevator and the first elevator tab is a left elevator tab, and the
second elevator is a right elevator and the second elevator tab is
a right elevator tab.
12. The system of claim 10, wherein the intentional delay is
between 6 and 20 seconds.
13. The system of claim 12, wherein the intentional delay is
between 8 and 14 seconds.
14. The system of claim 10, wherein the verification event is
moving the aircraft's flap handle out of an "up" detent.
15. The system of claim 10, wherein the verification event is a
detection of a failure of one or both of the primary and secondary
hydraulic systems of the aircraft.
16. The system of claim 10, wherein the first range is between
about 0.5.degree. and about 3.0.degree..
17. The system of claim 10, wherein the second range is between
about 0.0.degree. and about 0.4.degree..
18. The system of claim 10, wherein the third range is between
about 0.0.degree. and about 0.4.degree..
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a Continuation of U.S. application Ser.
No. 15/099,547, entitled "Method of Detecting Elevator Tab Failure"
and filed Apr. 14, 2016, which is incorporated herein by reference
in its entirety.
FIELD OF THE DISCLOSURE
[0002] This disclosure relates generally to detecting a latent
fault in an aircraft control system, and in particular, to
detecting a fault in the operation of elevator tabs used with an
aircraft's elevator.
BACKGROUND
[0003] The background description provided herein is for the
purpose of generally presenting the context of the disclosure. Work
of the presently named inventors, to the extent it is described in
this background section, as well as aspects of the description that
may not otherwise qualify as prior art at the time of filing, are
neither expressly nor impliedly admitted as prior art against the
present disclosure.
[0004] The "Next Generation" 737 (the "737NG") was designed to fly
higher, faster, carry heavier loads, and be more fuel efficient
than its predecessor, the 737 Classic, which is manufactured by the
Boeing Company. However, airlines flying the 737 Classic at the
time of the planned upgrade wanted to limit changes to specific
features of the 737 Classic to control costs associated with the
upgrade. Specifically, the airlines wanted the 737NG to have the
same type rating as the 737 Classic so that 737 Classic pilots
would not need costly recertification to fly the 737NG. In
addition, the airlines wanted the 737NG to have the same basic
design and same airframe as the 737 Classic to utilize the same
mechanics, tooling, and spare parts as the 737 Classic.
[0005] In accordance with this direction, the 737NG has the
same--or nearly the same--airframe, wing area, and control surfaces
as the 737 Classic, and the size of the 737 Classic elevators (a
control surface on the horizontal tail wings of an aircraft that
control pitch) were not changed on the larger and heavier 737NG.
However, the 737NG has more powerful engines and higher gross
weights than the 737 Classic, and the 737NG therefore requires more
aerodynamic authority then the existing 737 Classic elevators were
capable of developing. Consequently, with reference FIG. 2,
engineers developed dual-functioning elevator tabs 10a, 10b that
are disposed or positioned adjacent to a trailing edge of each
elevator 12a, 12b on each horizontal stabilizer 14a, 14b of the
737NG and that are displaceable relative to the respective elevator
12a, 12b. During normal flight operations, the elevator tabs 10a,
10b may function in a "balance" mode (illustrated in FIGS. 4B and
4D) as a portion of the elevators 12a, 12b. However, the elevator
tabs 10a, 10b are automatically reversed to an "anti-balance"
function (illustrated in FIGS. 4A and 4C) to displace relative to
each corresponding elevator 12a, 12b in two specific flight
conditions: (1) hydraulics engaged; and (2) flaps not
retracted.
[0006] The "balance" function of the elevator tabs 12a, 12b relates
to the redundant flight control functions of the 737NG. The 737NG
has two primary hydraulic systems, but the 737NG is capable of
operating with one or even both of those hydraulic systems failed.
In the case of dual failure of the hydraulic systems, the pilot can
still control the 737NG by physical strength combined with the help
of aerodynamic and mechanical devices and couplings. In such a
scenario, and as illustrated in FIGS. 4B and 4D, the "balance"
function of the elevator tabs 10a, 10b displaces the elevator tabs
10a, 10b in opposition to displacement of the elevators 12a, 12b.
That is, when the elevator 12a, 12b (i.e., a trailing edge 28a, 28b
of each elevator) pivots upwardly (as illustrated in FIG. 4B), the
corresponding elevator tab 10a, 10b (i.e., the trailing edge of the
elevator tabs 10a, 10b) pivots downwardly, and when the elevator
12a, 12b pivots downwardly (as illustrated in FIG. 4D), the
corresponding elevator tab 10a, 10b pivots upwardly. This
opposition movement applies an assisting load to the elevator
surface allowing the pilot to move the elevator 12a, 12b when
operating without hydraulic power. If the "balance" function of the
elevator tabs 10a, 10b was to fail when required, the 737NG could
not be manually controlled by a pilot.
[0007] A second elevator tab engagement scenario involves a takeoff
from a runway with a limited length when an engine fails just after
the aircraft has achieved V.sub.1 speed (the speed reached during
takeoff where it is just possible to stop the aircraft with the
remaining distance of runway). If V.sub.1 speed is exceeded, the
aircraft is required to complete the takeoff or it will overrun the
remaining runway if the takeoff is aborted. In such a takeoff, the
elevator tabs 10a, 10b perform an "anti-balance" function in which
the elevator tabs 10a, 10b displace in concert with the elevators
12a, 12b. That is, when the elevator 12a, 12b (i.e., the trailing
edge of the elevator 12a, 12b) pivots upwardly, the corresponding
elevator tab 10a, 10b (i.e., the trailing edge of the elevator tabs
10a, 10b) pivots upwardly (as illustrated in FIG. 4A), and when the
elevator 12a, 12b pivots downwardly, the corresponding elevator tab
10a, 10b pivots downwardly (as illustrated in FIG. 4C). This
in-concert displacement movement generates a greater elevator
surface hinge moment than the elevator of a 737 Classic, thereby
allowing the elevators 12a, 12b and elevator tabs 10a, 10b to
rotate the aircraft before reaching the end of that runway. As with
the "balance" function, if the "anti-balance" function was to fail
when required, the aircraft would not have sufficient control
authority to be assured of maintaining safe, continued flight.
[0008] While the elevator tabs perform a critical function in the
two scenarios described above, the operation of the elevator tabs
is entirely controlled by computer, and the pilots have no ability
to manually or specifically control their operation. In addition,
because the elevator tabs are not a part native to the 737 Classic,
no instrumentation is connected to or in communication with the
elevator tabs to directly detect failures, and the pilot (and
flight computer) has no indication that the elevator tabs are
functioning (or can function) properly. Accordingly, there is a
need for a method or system to indirectly detect proper operation
of the elevator tabs to ensure that the "balance" or "anti-balance"
functions are available in an emergency.
BRIEF SUMMARY OF THE DISCLOSURE
[0009] Techniques are provided for assessing and verifying proper
operation of a left elevator tab disposed at an end portion of a
left elevator of an aircraft and a right elevator tab disposed at
an end portion of a right elevator of the aircraft. The techniques
include determining the occurrence of a verification event that
includes movement of the left elevator tab relative to the left
elevator and the right elevator tab relative to the right elevator,
wherein the verification event occurs at a start time, wherein the
left elevator is at an initial rotational position and the right
elevator is at an initial rotational position at the start time.
The techniques also include determining a first rotational position
of the left elevator at a first time and a first rotational
position of the right elevator at the first time, and the first
time occurs after the start time. The first rotational position of
the left elevator at the first time is compared to the first
rotational position of the right elevator at the first time. If the
first rotational position of the left elevator at the first time is
not different than the first rotational position of the right
elevator at the first time by at least a first value, a first alert
is issued associated with the left elevator tab.
[0010] A second rotational position of the left elevator at a
second time and a second rotational position of the right elevator
at the second time are determined, and the second time occurs after
the first time. The difference between the start time and the
second time is equal to an intentional delay between functionality
of the left elevator tab and the right elevator tab. The second
rotational position of the left elevator at the second time is
compared to the second rotational position of the right elevator at
the elevator at the first time. If the second rotational position
of the right elevator at the second time is not within a second
range of the second rotational position of the left elevator at the
second time, a second alert is issued associated with the right
elevator tab. If (a) the second rotational position of the left
elevator at the second time is within a third range of the initial
rotational position of the left elevator at the start time and (b)
the second rotational position of the right elevator at the second
time is within the third range of the initial rotational position
of the right elevator at the start time, a third alert is issued
associated with both the left elevator tab and the right elevator
tab.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic diagram of an embodiment of the method
for verifying proper operation of a left elevator tab disposed at
an end portion of a left elevator of an aircraft and a right
elevator tab disposed at an end portion of a right elevator of the
aircraft;
[0012] FIG. 2 is a partial plan view of a rear portion of an
aircraft showing the horizontal stabilizers;
[0013] FIG. 3A is sectional view taken along line A-A and B-B of
FIG. 2;
[0014] FIG. 3B is sectional view taken along line A-A and B-B of
FIG. 2;
[0015] FIG. 3C is sectional view taken along line A-A and B-B of
FIG. 2;
[0016] FIG. 4A is sectional view taken along line A-A and B-B of
FIG. 2;
[0017] FIG. 4B is sectional view taken along line A-A and B-B of
FIG. 2;
[0018] FIG. 4C is sectional view taken along line A-A and B-B of
FIG. 2;
[0019] FIG. 4D is sectional view taken along line A-A and B-B of
FIG. 2;
[0020] FIG. 5A is partial sectional view taken along line A-A and
B-B of FIG. 2;
[0021] FIG. 5B is partial sectional view taken along line A-A and
B-B of FIG. 2;
[0022] FIGS. 6A to 6C are partial sectional views taken along line
A-A of FIG. 2 at a start time, a first time, and a second time,
respectively;
[0023] FIGS. 6D to 6F are partial sectional views taken along line
B-B of FIG. 2 at a start time, a first time, and a second time,
respectively;
[0024] FIGS. 7A to 7C are partial sectional views taken along line
A-A of FIG. 2 at a start time, a first time, and a second time,
respectively;
[0025] FIGS. 7D to 7F are partial sectional views taken along line
B-B of FIG. 2 at a start time, a first time, and a second time,
respectively;
[0026] FIGS. 8A to 8C are partial sectional views taken along line
A-A of FIG. 2 at a start time, a first time, and a second time,
respectively;
[0027] FIGS. 8D to 8F are partial sectional views taken along line
B-B of FIG. 2 at a start time, a first time, and a second time,
respectively;
[0028] FIGS. 9A to 9C are partial sectional views taken along line
A-A of FIG. 2 at a start time, a first time, and a second time,
respectively;
[0029] FIGS. 9D to 9F are partial sectional views taken along line
B-B of FIG. 2 at a start time, a first time, and a second time,
respectively;
[0030] FIG. 10 is a schematic view of a system for assessing and
verifying proper elevator tab operation in aircraft; and
[0031] FIG. 11 is a schematic view of modules of a process of the
system of the embodiment of FIG. 10.
DETAILED DESCRIPTION
[0032] As illustrated schematically in FIG. 1, a method is provided
for verifying proper operation of a first elevator tab (such as a
left elevator tab) disposed at an end portion of a first elevator
(such as a left elevator) of an aircraft and a second elevator tab
(such as a right elevator tab) disposed at an end portion of a
second elevator (such as a right elevator) of the aircraft. The
provided method utilizes an intentional delay (e.g., a ten-second
time delay) between the function of the left elevator tab and the
subsequent function of the right elevator tab when the flaps are
first extended. The techniques herein may be implemented by a
flight diagnostic system such as that provided in FIG. 10
(discussed below). The techniques analyze flight data of the
aircraft after one or more flights have been completed. The
analysis involves automatic identification of a verification event,
which may be the operation of the horizontal stabilizers of an
aircraft and includes movement of the left elevator tab relative to
the left elevator and the right elevator tab relative to the right
elevator, wherein the verification event occurs at a start time. In
an example, at the start of the verification event, the left
elevator tab moves relative to the left elevator. However, due to
the intentional delay, the right elevator tab does not move
relative to the right elevator. Because the deployment of the left
elevator tab relative to the left elevator creates aerodynamic
forces, the left elevator immediately displaces relative to its
position at or just prior to the initiation of the verification
event. By contrast, the right elevator does not displace
immediately after the initiation of the verification. Accordingly,
by analyzing flight data, the diagnostic system can infer or detect
a displacement of the left elevator tab following a verification
event, by confirming that the left elevator immediately displaced
(relative to both or either of its initial position or to the right
elevator).
[0033] While examples herein are described in reference to movement
of the left elevator tab preceding that of the right elevator tab,
it is noted that the converse ordering may be implemented with the
same results. The examples are described with the left elevator tab
leading, because that corresponds to the present operation
specifications of certain example aircraft.
[0034] At the expiration of the intentional delay, the right
elevator tab displaces relative to the right elevator, and this
displacement creates aerodynamic forces on the right elevator that
immediately displaces the right elevator relative to its position
at or just prior to the expiration of the intentional delay. By
analyzing flight data, a displacement of the right elevator tab can
be inferred or detected following the expiration of the intentional
delay by confirming that the right elevator immediately displaced
(relative to both or either of its initial position or to the left
elevator). The techniques therefore allow the proper operation of
the left elevator tab and the right elevator tab to be indirectly
verified by data analysis of existing flight parameters, thereby
avoiding the installation of costly new sensors, parts, and
instrumentation.
[0035] In an example implementation, available flight data (such
as, for example, data from a Digital Flight Data Recorder ("DFDR")
or a quick access recorder ("QAR")) is automatically analyzed by a
diagnostic system (e.g., FIG. 10) that employs an elevator tab
comparison algorithm to determine if a verification event has
occurred during a flight of the aircraft. In response to triggering
by a verification event, which may be an operation that involves
movement of the left elevator tab 10a (see FIG. 2) relative to the
left elevator 12a of the horizontal stabilizer 14 and the right
elevator tab 10b relative to the right elevator 12b of the
horizontal stabilizers, the system performs the assessment and
verification. The diagnostic system, which may operate on
historical available flight data or in real time on collected
flight data, can identify a verification event typically on each
flight. Because the operation of the elevator tabs 10a, 10b cannot
be directly controlled (or monitored) by the pilot, the
verification event is an operation of the elevators 12a, 12b that
automatically involves the rotational displacement of the left and
right elevator tabs 10a, 10b relative to the left and right
elevators 12a, 12b, respectively. An example of a verification
event may be, for example, a flight operation, such as moving the
aircraft's flap control lever out of the "up" detent or disengaging
either or both of the aircraft's redundant hydraulic systems that
operate the left and right elevators 12a, 12b. A further example of
a verification event may be a failure of one or both of the
redundant hydraulic systems.
[0036] The verification event occurs at a start time, and at this
start time and/or immediately prior to this start time (e.g., 0.5
to 0.25 seconds before), the left elevator 12a is at an initial
rotational position and the right elevator 12b is at an initial
rotational position. This and all positional and time information
relating the left and right elevator tabs 10a, 10b and the left and
right elevators 12a, 12b is stored as flight data (see, for
example, stored flight data 216 of FIG. 10). However, the flight
data may be real-time data (or may in part be real-time data) that
may be available to the controller 204 and/or stored the memory 206
of FIG. 10. The occurrence of the verification event at the start
time may be determined, for example, by the computer system 200 of
FIG. 10, which will be described in more detail below. The computer
system 200 may be particularly configured to automatically access
stored flight data (e.g., over a communication network), where such
access may be performed on a periodic basis determined by a
schedule or based on a number of flights since the last analysis or
some other event. In some examples, the computer system 200
accesses flight data based on a triggering event, whether in
real-time during flight or after a flight. The computer system 200
may automatically search for the verification event data stored in
the flight data and from there begin analysis and verification.
[0037] An example of an initial rotational position of the left
elevator 12a is provided in FIG. 3A, which illustrates that a
longitudinal axis 16a of the left elevator 12a is aligned (e.g.,
collinearly aligned) with a longitudinal axis 18a of the left
elevator tab 10a. The longitudinal axis 16a of the left elevator
12a and the longitudinal axis 18a of the left elevator tab 10a may
extend across the length of the left elevator tab 10a and the left
elevator 12a, respectively along the sectional line A-A of FIG. 2.
In some embodiments, the longitudinal axis 16a of the left elevator
12a and the longitudinal axis 18a of the left elevator tab 10a may
bisect or substantially bisect the left elevator tab 10a and the
left elevator 12a, respectively along the sectional line A-A of
FIG. 2.
[0038] At (and/or just prior to) the start time, the left elevator
tab 10a and the left elevator 12a act as a single control surface
that rotates as a unit relative to a portion of the left horizontal
stabilizer 14a about a left elevator rotational point 20a, as
illustrated in FIG. 3A. Thus, at the initial rotational position of
the left elevator 12a, the longitudinal axis 16a of the left
elevator 12a and the longitudinal axis 18a of the left elevator tab
10a may be aligned with a longitudinal axis 22a of the left
horizontal stabilizer 14a, as illustrated in FIG. 3A. In addition,
the longitudinal axis 16a of the left elevator 12a and the
longitudinal axis 18a of the left elevator tab 10a may form an
acute angle (either clockwise or counterclockwise) with the
longitudinal axis 22a of the left horizontal stabilizer 14a, as
illustrated in FIGS. 3B and 3C.
[0039] Also at the start time and/or immediately prior to this
start time (e.g., 0.5 to 0.25 seconds before), the right elevator
12b is at an initial rotational position and the right elevator 12b
is at an initial rotational position. An example of an initial
rotational position of the right elevator 12b is provided in FIG.
3A, which illustrates that a longitudinal axis 16b of the right
elevator 12b is aligned (e.g., collinearly aligned) with a
longitudinal axis 18b of the right elevator tab 10b. The
longitudinal axis 16b of the right elevator 12b and the
longitudinal axis 18b of the right elevator tab 10b may extend
across the length of the right elevator tab 10b and the right
elevator 12b, respectively along the sectional line B-B of FIG. 2.
In some embodiments, the longitudinal axis 16b of the right
elevator 12b and the longitudinal axis 18b of the right elevator
tab 10b may bisect or substantially bisect the right elevator tab
10b and the right elevator 12b, respectively along the sectional
line B-B of FIG. 2.
[0040] At (and/or just prior to) the start time, the right elevator
tab 10b and the right elevator 12b act as a single control surface
that rotates as a unit relative to a portion of the right
horizontal stabilizer 14b about a right elevator rotational point
20b, as illustrated in FIG. 3A. Thus, at the initial rotational
position of the right elevator 12b, the longitudinal axis 16b of
the right elevator 12b and the longitudinal axis 18b of the right
elevator tab 10b may be aligned with a longitudinal axis 22a of the
right horizontal stabilizer 14b, as illustrated in FIG. 3A. In
addition, the longitudinal axis 16b of the right elevator 12b and
the longitudinal axis 18b of the right elevator tab 10b may form an
acute angle (either clockwise or counterclockwise) with the
longitudinal axis 22b of the right horizontal stabilizer 14b, as
illustrated in FIGS. 3B and 3C.
[0041] At a first time, which occurs immediately or nearly
immediately after the verification event, the left elevator tab 10a
rotates relative to the left elevator 12a, while due to the
intentional delay, the right elevator tab 10b does not rotate or
displace relative to the right elevator 12b. The first time may
occur after the start time but before the intentional delay
expires, and the first time may be any length of time that allows a
displacement (i.e., a statistically significant rotational
displacement) of the left elevator 12a relative to the right
elevator 12b to be detected by analyzing flight data. For example,
the first time may occur between 0.0 to 1.0 second after the start
time.
[0042] The left elevator tab 10a may rotatably displace in one of
two directions relative to the left elevator 12 (or relative to a
point on the left elevator). As illustrated in FIG. 5A (in which
the left horizontal stabilizer 14a is eliminated for clarity), the
left elevator tab 10a may rotate counter-clockwise about a left tab
rotation point 24a that is disposed at or adjacent to a leading
edge 26a of the left elevator tab 10a (and/or at or adjacent to a
trailing edge 28a of the left elevator 12a). Such a
counter-clockwise rotation of the left elevator tab 10a is involved
in the "balance" function of the left elevator tab 10a when the
left elevator 12a rotates clockwise relative to the left elevator
12a (or clockwise about the left elevator rotational point 20a), as
illustrated in FIG. 4D. In addition, a counter-clockwise rotation
of the left elevator tab 10a is involved in the "anti-balance"
function of the left elevator tab 10a when the left elevator 12a
rotates counter-clockwise relative to the left elevator 12a (or
counter-clockwise about the left elevator rotational point 20a), as
illustrated in FIG. 4A.
[0043] Referring to FIG. 5B (in which the left horizontal
stabilizer 14a is eliminated for clarity), the left elevator tab
10a may also rotate clockwise about the left tab rotation point
24a. Such a clockwise rotation of the left elevator tab 10a is
involved in the "balance" function of the left elevator tab 10a
when the left elevator tab 10a rotates counter-clockwise relative
to the left elevator 12a (or counter-clockwise about the left
elevator rotational point 20a), as illustrated in FIG. 4B. In
addition, a clockwise rotation of the left elevator tab 10a is
involved in the "anti-balance" function of the left elevator tab
10a when the left elevator tab 10a rotates clockwise relative to
the left elevator 12a (or clockwise about the left elevator
rotational point 20a), as illustrated in FIG. 4B.
[0044] At this first time, the rotated or deployed left elevator
tab 10a (in either "balance" or `anti-balance" mode) will have
different aerodynamic characteristics that the right elevator 12b
and the right elevator tab 10b. Accordingly, the left elevator 12a
will be in a different relative position than the right elevator
12b at the first time when the flight data is analyzed.
Specifically, as illustrated in FIG. 6A (with the "anti-balance"
configuration illustrated as an example only), the longitudinal
axis 16a of the left elevator 12a (and the longitudinal axis 18a of
the left elevator tab 10a) extends through a left reference axis
30a at (or just prior to) the start time. At the first time, as
illustrated in FIG. 6B, due to aerodynamic forces on the left
elevator tab 10a, the longitudinal axis 16a of the left elevator
12a makes an angle 32a with the left reference axis 30a at (or just
prior to) the start time, and this position of the left elevator
12a may be the first rotational position of the left elevator 12a
at the first time. The angle 32a may be an acute angle that may be
clockwise or counter-clockwise, and the value of the angle may
depend on many variables, such as airspeed and/or initial angle of
the left elevator 12a relative to the left horizontal stabilizer
14a, airspeed, for example.
[0045] At the start time (illustrated in FIG. 6D) and at the first
time (illustrated in FIG. 6E), and due to the intentional delay,
the right elevator tab 10 has not rotated relative to the right
elevator 12a. That is, at both the start time and at the first
time, the longitudinal axis 16b of the right elevator 12b (and the
longitudinal axis 18b of the right elevator tab 10b) extends
through a right reference axis 30b that is aligned with the left
reference axis 30a of the left elevator 12a, and this position of
the right elevator 12b may be the first rotational position of the
right elevator 12b at the first time.
[0046] The right reference axis 30b of the right elevator 12b is
aligned with (or corresponds to) the left reference axis 30a of the
left elevator 12a in space. That is, a plane may extend through or
along each of the left reference axis 30a and the right reference
axis 30b, and the plane may be parallel to an axis or rotation of
the left elevator 12a (that extends through the left elevator
rotational point 20a of FIG. 3A) and an axis or rotation of the
right elevator 12b (that extends through the right elevator
rotational point 20b of FIG. 3A).
[0047] Accordingly, at the first time, the flight data may be
analyzed to compare the first rotational position of the left
elevator 12a (illustrated in FIG. 6B) to the first rotational
position of the right elevator 12b (illustrated in FIG. 6E). This
analysis of the flight data (as well as all analysis of flight data
described in the following sections) may be performed by the
computer system 200 of FIG. 10, which will be described in more
detail below. If the first rotational position of the left elevator
12a at the first time is different than the first rotational
position of the right elevator at the first time by at least a
first value or within a first range, an alert may be issued that
the left elevator tab 10a is operating properly. For example, if
the angle 32a between the left reference axis 30a and the
longitudinal axis 16a of the left elevator 12a is at a desired
value or within a desired range (for example only, 0.5.degree. to)
3.0.degree. and the angle 32b between the right reference axis 30b
and the longitudinal axis 16b of the right elevator 12b is at a
desired value or within a desired range (for example only,
0.0.degree. to) 0.4.degree., an alert may be issued that the left
elevator tab 10a is operating properly. An example of proper
operation of the left elevator tab 10a between the start time and
the first time can be found in FIGS. 6A and 6B.
[0048] In addition, or alternatively, the flight data may be
analyzed to compare the first rotational position of the left
elevator 12a (illustrated in FIG. 6B) to the position of the first
rotational position of the left elevator 12a at or just prior to
the start time (illustrated in FIG. 6A). If the first rotational
position of the left elevator 12a at the first time is different
than the rotational position of the left elevator 12a at the start
time by at least a first value or within a first range, an alert
may be issued that the left elevator tab 10a is operating properly.
For example, if the angle 32a between the left reference axis 30a
and the longitudinal axis 16a of the left elevator 12a is at a
desired value or within a desired range (for example only,
0.5.degree. to) 3.0.degree. at the first time, and the angle 32a
between the left reference axis 30a and the longitudinal axis 16a
of the left elevator 12a is at a desired value or within a desired
range (for example only, 0.0.degree. to 0.4.degree.) at the start
time, an alert may be issued that the left elevator tab 10a is
operating properly.
[0049] As illustrated in FIGS. 7A to 7F, analysis of the flight
data may show that the left elevator tab 10a is not functional. For
example, if analysis of the flight data shows the first rotational
position of the left elevator 12a at the first time is not
different than (or is equal or approximately equal to) the first
rotational position of the right elevator 12b at the first time,
the first alert may be issued. As another example, if analysis of
the flight data shows that the angle 32a between the left reference
axis 30a and the longitudinal axis 16a of the left elevator 12a is
not at a desired value or within a desired range (for example only,
0.5.degree. to 3.0.degree.) at the first time (as illustrated in
FIG. 7B) and/or if the difference in the angle 32a at the first
time is not greater than a value or within a desired range (for
example only, 0.5.degree. to 3.0.degree.) then the angel 32a at the
start time (illustrated in 7A), then the first alert may be
issued.
[0050] At the expiration of the intentional delay, which occurs at
a second time, the right elevator tab 10a rotationally displaces
relative to the right elevator 12a. The intentional delay may be
any suitable length of time between operation of the left elevator
tab 10a and the right elevator tab 10b. For example, the
intentional delay may be 5 to 20 seconds, for example. More
specifically, the intentional delay may be 5 to 20 seconds, or may
be 10 seconds. If the intentional delay is triggered by the
verification event that occurs at the start time, the second time
is the value of the intentional delay.
[0051] Between the start time (and the first time) and just prior
to the second time, the right elevator tab 10b and the right
elevator 12b act as a single control surface that rotates as a unit
relative to a portion of the right horizontal stabilizer 14b about
a right elevator rotational point 20b, as illustrated in FIG. 3A.
However, at the second time, the right elevator tab 10b may
rotatably displace in one of two directions relative to the right
elevator 12b (or relative to a point on the right elevator 12b). As
illustrated in FIG. 5A (in which the right horizontal stabilizer
14b is eliminated for clarity), the right elevator tab 10a may
rotate counter-clockwise about a right tab rotation point 24b that
is disposed at or adjacent to a leading edge 26b of the right
elevator tab 10b (and/or at or adjacent to a trailing edge 28b of
the right elevator 12b). Such a counter-clockwise rotation of the
right elevator tab 10b is involved in the "balance" function of the
right elevator tab 10b when the right elevator tab 10b rotates
clockwise relative to the right elevator 12a (or clockwise about
the right elevator rotational point 20b), as illustrated in FIG.
4D. In addition, a counter-clockwise rotation of the right elevator
tab 10b is involved in the "anti-balance" function of the right
elevator tab 10b when the right elevator 12b rotates
counter-clockwise relative to the right elevator 12b (or
counter-clockwise about the right elevator rotational point 20b),
as illustrated in FIG. 4A.
[0052] At or immediately after the expiration of the intentional
delay (i.e., at the second time), the right elevator tab 10b makes
(or finished making) a displacement that corresponds to the
displacement of the left elevator tab 10a. That is, the right
elevator tab 10b displaces (e.g., rotationally displaces) in the
same direction and to the same degree as the left elevator tab 10a
(illustrated in FIGS. 4A to 4D), with the only difference between
the two being the timing of the start of the rotational
displacement. For example, if the left elevator 12a is rotated
counter-clockwise and the left elevator tab 10a is in the
"anti-balance" position of FIG. 4A, than the right elevator 12b is
rotated counter-clockwise (to the same degree as the left elevator
12a) and the right elevator tab 10b is in the "anti-balance"
position of FIG. 4A (to the same degree as the left elevator tab
10a). Put another way, after the expiration of the intentional
delay following the verification event, the left elevator 12a and
the left elevator tab 10a should have a cross-section that is
identical or nearly identical to the right elevator 12b and the
right elevator tab 10b.
[0053] At this second time, the rotated or deployed right elevator
tab 10b (in either "balance" or `anti-balance" mode) will have the
same aerodynamic characteristics of the deployed left elevator tab
12a (also in either "balance" or `anti-balance" mode). Accordingly,
the right elevator 12b will move from the first rotational position
of FIG. 6E into the same (or nearly the same) relative position as
the left elevator 12a at or slightly after the second time when the
flight data is analyzed. Specifically, as illustrated in FIG. 6F
(with the "balance" configuration illustrated as an example only),
the longitudinal axis 16b of the right elevator 12b makes an angle
32b with the right reference axis 30b due to aerodynamic forces
acting on the right elevator tab 10b, and this position of the
right elevator 12b may be the second rotational position of the
right elevator 12b at the second time. Because the position of the
left elevator tab 10a and the left elevator 12a do not change from
the first time to the second time, the second rotational position
of the left elevator 12a at the second time is equal to or
approximately equal to the first rotational position of the left
elevator 12a at the first time. That is, the angle 32a does not
change between the first time and the second time.
[0054] Consequently, at the second time, the flight data may be
analyzed to compare the first rotational position of the right
elevator 12b (illustrated in FIG. 6E) to the second rotational
position of the right elevator 12b (illustrated in FIG. 6F). If the
second rotational position of the right elevator 12b at the second
time is different than the first rotational position of the right
elevator 12b at the first time by at least a first value or within
a first range, an alert may be issued that the right elevator 12b
is operating properly. For example, if the angle 32b between the
right reference axis 30b and the longitudinal axis 16b of the right
elevator 12b is at a desired value or within a desired range (for
example only, 0.0.degree. to 0.4.degree.) at the first time, and if
the angle 32b between the right reference axis 30b and the
longitudinal axis 16b of the right elevator 12b is at a desired
value or within a desired range (for example only, 0.5.degree. to
3.0.degree.) at the second time, an alert may be issued that the
right elevator tab 10a is operating properly. An example of proper
operation of the right elevator tab 10a between the first time and
the second time can be found in FIGS. 6E and 6F.
[0055] In addition (or alternatively), the flight data may be
analyzed to compare the second rotational position of the right
elevator 12b (illustrated in FIG. 6F) to the second rotational
position of the left elevator 12a (illustrated in FIG. 6C). If the
second rotational position of the right elevator 12b at the second
time is equal to (or approximately equal to) or is the same as the
second rotational position of the left elevator 12a at the second
time (relative to the left reference axis 30a and the right
reference axis 30b), the right elevator tab 10b is functioning
properly. An alert may then be issued that the right elevator tab
10b is operating properly. For example, if the angle 32b between
the right reference axis 30b and the longitudinal axis 16b of the
right elevator 12b is at a desired value or within a desired range
(for example only, 0.5.degree. to 3.0.degree.) at the second time,
and if the angle 32a between the left reference axis 30a and the
longitudinal axis 16a of the left elevator 12a is at a desired
value or within a desired range (for example only, 0.5.degree. to
3.0.degree.) at the second time, an alert may be issued that the
right elevator tab 10a is operating properly.
[0056] As illustrated in FIGS. 8A to 8F, analysis of the flight
data may show that the left elevator tab 10a is functional but that
the right elevator tab 10b is not functional. For example, at the
second time, the flight data is analyzed to compare the first
rotational position of the right elevator 12b (illustrated in FIG.
8E) to the second rotational position of the right elevator 12b
(illustrated in FIG. 8F). If the second rotational position of the
right elevator 12b at the second time is not different than (or is
approximately equal to) the first rotational position of the right
elevator 12b at the first time, a second alert may be issued that
the right elevator 12b is not operating properly. For example, if
the angle 32b between the right reference axis 30b and the
longitudinal axis 16b of the right elevator 12b is at a desired
value or within a desired range (for example only, 0.0.degree. to
0.4.degree.) at the first time, and if the angle 32b between the
right reference axis 30b and the longitudinal axis 16b of the right
elevator 12b is not at a desired value or within a desired range
(for example only, 0.5.degree. to 3.0.degree.) at the second time,
the second alert may be issued.
[0057] In addition (or alternatively), the flight data may be
analyzed to compare the second rotational position of the right
elevator 12b (illustrated in FIG. 8F) to the second rotational
position of the left elevator 12a (illustrated in FIG. 8C). If the
second rotational position of the right elevator 12b at the second
time is not equal to (or approximately equal to) or within a range
of (for example only, 0.0.degree. to 0.4.degree.) the second
rotational position of the left elevator 12a at the second time
(relative to the left reference axis 30a and the right reference
axis 30b), the second alert may be issued. It may also be desired
that the angle 32a between the left reference axis 30a and the
longitudinal axis 16a of the left elevator 12a is at a desired
value or within a desired range (for example only, 0.5.degree. to
3.0.degree.) before the second alert is issued.
[0058] As illustrated in FIGS. 9A to 9F, analysis of the flight
data may show that the left elevator tab 10a is not functional and
that the right elevator tab 10b is not functional. For example, as
a first determining condition, if analysis of the flight data shows
the first rotational position of the left elevator 12a at the first
time (see FIG. 9B) is not different than (or is equal or
approximately equal to) the first rotational position of the right
elevator 12b (see FIG. 9E) at the first time, then the left
elevator tab 10a is not functional. In addition, as a second
determining condition, if analysis of the flight data shows the
second rotational position of the right elevator 12a at the first
time (see FIG. 9F) is not different than (or is equal or
approximately equal to) the first rotational position of the right
elevator 12b (see FIG. 9E) at the first time, then the right
elevator tab 10b is not functional. If both the first and second
determining condition are satisfied, then the a third alert is
issued, with the third alert corresponding to a failure of both the
left and right elevator tabs 10a, 10b.
[0059] An alternative analysis of the flight data may show that the
left elevator tab 10a is not functional and that the right elevator
tab 10b is not functional. For example, as a first determining
condition, if the second rotational position of the left elevator
12a at the second time (see FIG. 9C) is within a range (0.0 to
0.4.degree.) of the initial rotational position of the left
elevator at the start time (see FIG. 9C) and if the second
rotational position of the right elevator 12b at the second time
(see FIG. 9F) is within the range (0.0 to 0.4.degree.) of the
initial rotational position of the right elevator 12b at the start
time (see FIG. 9D), the third alert is issued a. The range is an
angle 32a between the left reference axis 30a and the longitudinal
axis 16a of the left elevator 12a or an angle 32b between the right
reference axis 30b and the longitudinal axis 16b of the right
elevator 12b.
[0060] The flight data may be analyzed and compared (and alerts may
be issued) by any system or software (or combination of systems or
software) known in the art. For example, the flight data may be
analyzed and compared by an algorithm, such as a filter placed
within the recorded flight data. In some systems, a computing
device may be employed, and the computing device may include a
memory and a processor, with logic stored on the memory and
executable by the processor.
[0061] The flight data may be analyzed for proper operation of the
left and right elevator tabs 10a, 10b at any time, and such an
analysis may be formed at any suitable time. For example, the
flight data may be analyzed for proper operation of the left and
right elevator tabs 10a, 10b after every flight of a particular
aircraft, or periodically over a sample of a fleet of aircraft.
[0062] In contemplated embodiments, the data may be analyzed in
real time (either on board the aircraft and/or remote from the
aircraft to determine proper operation of the left and right
elevator tabs 10a, 10b. If either or both of the left and right
elevator tabs 10a, 10b, are determined to be non-functional, a
first, second, or third alert can be issued to the pilot, who can
then take corrective action.
[0063] FIG. 10 illustrates a computer system 200 for assessing and
verifying operation of elevator tabs. The computer system 200
accesses available stored flight data 216, such as a flight data
database implemented as a Digital Flight Data Recorder ("DFDR"), a
quick access recorder ("QAR") or other database, to assess
operation of elevator tabs, in accordance with the examples
described herein. The system 200 may be implemented in a desktop
computer, laptop computer, tablet computer, mobile device,
smart-phone, network-enabled device, cloud based server, an
application server, a web server, etc. The computer system 200 may
represent a single one of these processing machines or a
distributed combination of such processing machines.
[0064] A signal-processing device 202 (or "signal processor" or
"diagnostic device") is coupled the stored flight data 216 through
a wired or wireless communication network. The signal-processing
device 202 may have a controller 204 operatively connected to a
database 214 via a link 222 connected to an input/output (I/O)
circuit 212. It should be noted that, while not shown, additional
databases may be linked to the controller 204 in a known manner.
The controller 204 includes a program memory 206, one or more
processors 208 (may be called microcontrollers or a
microprocessors), a random-access memory (RAM) 210, and the
input/output (I/O) circuit 212, all of which are interconnected via
an address/data bus 220. It should be appreciated that although
only one processor 208 is shown, the controller 204 may include
multiple microprocessors 208. Similarly, the memory of the
controller 204 may include multiple RAMs 210 and multiple program
memories 206. Although the I/O circuit 212 is shown as a single
block, it should be appreciated that the I/O circuit 212 may
include a number of different types of I/O circuits. The RAM(s) 210
and the program memories 206 may be implemented as semiconductor
memories, magnetically readable memories, and/or optically readable
memories, for example. A link 224, which may include one or more
wired and/or wireless (Bluetooth, WLAN, etc.) connections, may
operatively connect the controller 204 to stored flight data 216
through the I/O circuit 212. In some examples, a (pneumatic,
electronic, optical, or some combination thereof) flight controller
225 is coupled to the stored flight data 216, through the link 224,
to allow for automated control of the operation of the elevator
tabs in the event of a fault condition or other operation
automatically determined.
[0065] The program memory 206 and/or the RAM 210 may store various
applications (i.e., machine readable instructions) for execution by
the processor 208. For example, an operating system may generally
control the operation of the signal-processing device 202 and
provide a user interface for the signal-processing device 202 to
implement the stages of the method 100 of FIG. 1. The program
memory 206 and/or the RAM 210 may also store a variety of
subroutines 232 for accessing specific functions of the
signal-processing device 202. By way of example, and without
limitation, the subroutines 232 may include, among other things: a
subroutine for determining an occurrence of a verification event
that includes movement of a first elevator tab (e.g., a left
elevator tab) relative to a first elevator (e.g., the left
elevator) and a second elevator tab (e.g., a right elevator tab)
relative to a second elevator (e.g., a right elevator), wherein the
verification event occurs at a start time, wherein the first
elevator is at an initial rotational position and the second
elevator is at an initial rotational position at the start time; a
subroutine for determining a first rotational position of the first
elevator at a first time and a first rotational position of the
second elevator at the first time, the first time occurring after
the start time; a subroutine for comparing the first rotational
position of the first elevator at the first time to the first
rotational position of the second elevator at the first time; a
subroutine to issue a first alert associated with the first
elevator tab if the first rotational position of the first elevator
at the first time is not different than the first rotational
position of the second elevator at the first time by at least a
first value or by a first range; a subroutine to compare the second
rotational position of the first elevator at the second time to the
second rotational position of the second elevator at the elevator
at the second time; a subroutine to issue a second alert associated
with the second elevator tab if the second rotational position of
the second elevator at the second time is not within a second range
of the second rotational position of the first elevator at the
second time; and a subroutine to determine that if (a) the second
rotational position of the first elevator at the second time is
within a third range of the initial rotational position of the
first elevator at the start time and (b) the second rotational
position of the second elevator at the second time is within the
third range of the initial rotational position of the second
elevator at the start time, a third alert is issued associated with
both the first elevator tab and the second elevator tab.
[0066] As previously explained, the subroutines 232 may include a
subroutine to generate an alert and/or alarm condition, for
example, using the display 226. That alert and/or alarm condition
may be displayed as a web page, mobile device alert, tactile alert
or alarm (e.g., via a vibrating function of a smartwatch or
smartphone), or any other suitable visual and/or tactile (haptic)
display. The subroutines 232 may communicate this alert and/or
alarm condition to a separate computing device connected to the
system 200 through a network connection. Such separate computing
devices may include a server, laptop computer, handheld computer,
monitor, mobile device such as a cellular phone or Wi-Fi-enabled
tablet, or other device. The subroutines 232 may include a
subroutine to communicate the alert or other analysis thereof to a
flight control system for operation of the elevators, elevator
tabs, or other system to compensate for a detected fault condition.
The subroutines 232 may also include other subroutines, for
example, implementing software keyboard functionality, interfacing
with other hardware in the signal-processing device 202, etc. The
subroutines 232 may also include other subroutines, for example,
implementing software keyboard functionality, interfacing with
other hardware in the signal-processing device 202, etc. The
program memory 206 and/or the RAM 210 may further store data
related to the configuration and/or operation of the
signal-processing device 202, and/or related to the operation of
the one or more subroutines 232. For example, the data may be data
gathered by in the flight data 216, data determined and/or
calculated by the processor 208, etc. In addition to the controller
204, the signal-processing device 202 may include other hardware
resources. The signal-processing device 202 may also include
various types of input/output hardware such as a visual display 226
and input device(s) 228 (e.g., keypad, keyboard, etc.). In an
embodiment, the display 226 is touch-sensitive, and may cooperate
with a software keyboard routine as one of the software routines
232 to accept user input. It may be advantageous for the
signal-processing device 202 to communicate with a broader flight
control systems (not shown) through any of a number of known
networking devices and techniques.
[0067] The controller 204 may include any number of modules to
analyze flight data to verify proper operation of the left and
right elevator tabs 10a, 10b, and these modules may represent
software code or hardware or stored instructions that implement the
techniques described herein. For example, as illustrated in FIG.
11, the controller 204 may include a flight data module 302 that
includes the aircraft's (or multiple aircrafts') flight data. The
controller 204 may also include a verification event detection
module 304 that analyzes the flight data to determine the
occurrence of a verification event that includes movement of a
first elevator tab (e.g., the left elevator tab 10a) relative to
the first elevator (e.g., the left elevator 12a) and the second
elevator tab (the right elevator tab 10b) relative to the second
elevator (the right elevator 12b). The verification event detection
module 304 may also determine an initial rotational position of the
first elevator and an initial rotational position of the second
elevator at a start time, which is the time or point in time that
the verification event occurred.
[0068] The controller 204 may additionally include a first
rotational position module 306 to analyze the flight data to
determine a first rotational position of the first elevator at a
first time and a first rotational position of the second elevator
at the first time, the first time occurring after the start
time.
[0069] The controller 204 may include a first comparison module 308
to compare the first rotational position of the first elevator at
the first time to the first rotational position of the second
elevator at the first time.
[0070] The controller 204 may include a first detection module 310
that issues a first alert associated with the first elevator tab if
the first rotational position of the first elevator at the first
time is not different than the first rotational position of the
second elevator at the first time by at least a first value or by a
first range. The first detection module 310 may also issue a first
alert based on other parameters described earlier to determine if
the first elevator tab is functional.
[0071] The controller 204 may additionally include a second
rotational position module 312 to analyze the flight data to
determine a second rotational position of the first elevator at a
second time and a second rotational position of the second elevator
at the second time. The second time occurs after the first time and
the difference between the start time and the second time being
equal to an intentional delay between functionality of the first
elevator tab and the second elevator tab.
[0072] The controller 204 may include a second comparison module
314 to compare the second rotational position of the first elevator
at the second time to the second rotational position of the second
elevator at the elevator at the second time.
[0073] The controller 204 may include a second detection module 316
that issues a second alert associated with the second elevator tab
if the second rotational position of the second elevator at the
second time is not within a second range of the second rotational
position of the first elevator at the second time. The second
detection module 316 may also issue a second alert based on other
parameters described earlier to determine if the second elevator
tab is functional.
[0074] The controller 204 may include a third detection module 318
that issues a third alert associated with both the first elevator
tab and the second elevator tab if (a) the second rotational
position of the first elevator at the second time is within a third
range of the initial rotational position of the first elevator at
the start time and (b) the second rotational position of the second
elevator at the second time is within the third range of the
initial rotational position of the second elevator at the start
time. The third detection module 318 may also issue a third alert
based on other parameters described earlier to determine if both
the first and second elevator tabs are functional.
[0075] The controller 204 may also include an optional corrective
measures flight data control interface module 320 that may initiate
corrective measures based on the issuance of a first, second,
and/or third alert. The corrective measures may provide information
that identifies the fault and the aircraft, for example. The
corrective measures may also be in-flight instructions or relating
to the first, second, and/or third alert.
[0076] The controller 204 may analyze the flight data after a
flight has occurred or may perform real-time analysis of flight
data. Although the modules 312-320 are represented as discrete,
independent modules in FIG. 11, a single module (or multiple
modules) could perform any of the functionalities associated with
any of the modules provided in FIG. 11.
[0077] While various embodiments have been described above, this
disclosure is not intended to be limited thereto. Variations can be
made to the disclosed embodiments that are still within the scope
of the appended claims. For example, the first elevator tab may be
the right elevator tab disposed at an end portion of the first
elevator, which is the right elevator of the aircraft.
Correspondingly, the second elevator tab may be the left elevator
tab disposed at an end portion of the second elevator, which may be
the left elevator of the aircraft.
* * * * *