Appendix 2
b. Process. The test engineer evaluates the DFDRS recorded data based on the data ranges for each parameter.
(1) The test engineer must use the predetermined list of data points to be recorded as identified in paragraph 3.
(2) By controlling the aircraft input, the conventional form of the digital output is to be recorded.
(3) The conventional form of the digital output must be converted into decimal units. A capable tool (i.e., calculator, computer application, etc.) makes this conversion easier.
c. Data Application/Desired Output. This paragraph identifies the required data to be produced by following Procedure B.
(1) The parameter’s static and full dynamic ranges and recorded outputs should be stored or displayed. Use a method similar or comparable to that used in Procedure A (i.e., plot EU as a function of decimal units).
(2) Once data storage or display is complete, this information is used in paragraph 5 to compare against the baseline to determine compliance with the CFR.
5. REVERSE DFDR DATA CO RRELATION PROCEDURE C. This paragraph outlines the process to determine compliance with the CFR. It defines a comparative assessment between actual aircraft measured data and manufacturer system-specific data. If regulatory compliance is not determined, then the operator must choose to either repair, recorrelate, or replace the noncompliant system. Procedures A and B must be accomplished before completing Procedure C.
a. Requirements. This paragraph identifies the required data items needed to accomplish DFDR data reverse correlation. The recorded conversion data from Procedures A and B are required to begin Procedure C. If applicable, the parameter’s resolution from Procedure A is also required and is critical in determining an acceptable parameter correlation.
(1) Procedure A contributes manufacturer-specific system conversion and parameter information. For each parameter, a baseline with digital tolerances was established. If applicable, an EU to decimal unit representation of expected DFDR system operational performance was created. In the following discussion, data obtained from Procedure A will be referred to as “expected” data.
(2) Procedure B contributes aircraft-specific DFDR data from testing the static and full dynamic range of each parameter. The number of data points recorded is discretionary, greater numbers of data points increase the probability of the parameter being in compliance. The actual data stored in an aircraft’s DFDR needs to be verified through a comparative assessment with the data from Procedure A. In the following discussion, data obtained from Procedure B will be referred to as “measured” data.
Appendix 2
b. Process. This paragraph outlines the steps to complete the analysis and to determine compliance.
(1) Once the data from Procedure A and B are present, a comparative assessment is required. This analysis relates an aircraft-specific DFDR operational performance to the expected DFDR operational performance as documented by the system manufacturer.
NOTE: We recommend use of a graphing program with the capability to calculate “R” numbers. It is useful to plot the measured data points on the expected baseline graph. An “R” number should be produced to read 0.99 or greater in order to achieve regulatory compliance.
(2) First, select the EU values for which there are both expected and measured data.
Then, obtain the decimal unit values for each data pair. Use the following statement to compare the decimal unit values for the expected and measured data.
(3) If the measured data, denoted as mX , is within the expected data plus or minus half the resolution, denoted as 2resXe ± , then the parameter data value is known with 100 percent certainty to be in compliance. This statement is represented mathematically by, 2 resXX2resX eme +≤≤− The above comparative analysis must be made for each parameter’s operational range.
c. Data Application/Desired Output. This paragraph provides recommendations and information based on the conclusions from the analysis in paragraph 5b. The analysis in paragraph 5b concludes that:
(1) The design is in compliance with 14 CFR,
(2) The system relating to the applicable parameter sensor needs to be recalibrated, or
(3) The parameter must be recorrelated.
d. Ensure Compliance. The final step is to ensure that the parameters with measured data not within the expected data limits are in compliance. To reach conclusion (2) above, the data must be analyzed and a consistent discrepancy must be identified between the measured and expected data values. While the applicable system is in a neutral state, adjust to within the limits.
Conclusion (3) above is a result of random inaccurate trends identified in the comparison analysis. The applicable system needs to be repaired, or replaced.
Appendix 3 APPENDIX 3. DIGITAL FLIGHT DATA RECORDER PARAMETER
REQUIREMENTS FLOWCHART
Appendix 3
Appendix 3 B Manufactured on or before 10/11/91?
NO Flight Data Acquisition Unit (FDAU) as of 07/16/1996?
Part 121 Flight Recorder Parameter Requirements, §121.344 YES YES YES No FDAU More than two engines?
§121.344(b) Appdx B. Record 17 parameters.
Parameter 18 req’d based on capacity.
§121.344(b) Appdx B. Record 18 parameters.
YES NO Analog FDAU §121.344(b) Appdx M. Record 22 parameters.
Parameters 12-17, single source allowed.
§121.344(c) Appdx M. Record 22 parameters*.
Parameters 12-14, single source allowed.
Digital FDAU NO Manufactured after 8/20/2002?
§121.344(f) Appdx M 88 parameters Manufactured after 8/18/2000?
NO YES §121.344(e) Appdx M 57 parameters* §121.344(d) Appdx M 34 parameters* NO B.2 Page 3-4 §121.343 B.1 D Page 3-5 §121.344a END * Commensurate with capacity, any other parameters (of 88) that have information sources installed and connected to the recording system.
From Page 3-2 §91.609 From Page 3-1 Aircraft listed in §121.344(l)(2)?
10-19 passenger seats?
YES NO US registered or brought on US Op Specs after 10/11/91?
YES B.3 Page 3-8 §135.152 NO
Appendix 3 Manufactured after 10/11/1991?
§121.343(f) Appdx B 29 mandatory and 12 recommended parameters.
NO YES §121.343(d) Appdx B 17 mandatory parameters.
NO B.2 Part 121 Flight Recorder Parameter Requirements, §121.343 From Page 3-3 §121.344 Has a digital databus & ARINC 717 DFDAU?
Manufactured after 5/26/1989, or type certificated after 9/30/1969?
YES §121.343(c) Appdx B 11 mandatory parameters.
YES NO §121.343(f) Appdx B 29 mandatory and 12 recommended parameters.
END
Appendix 3 Manufactured Before 8/18/1997?
§121.344a(b)(1) Appdx M 57 parameters***.
B.3 Part 121 Flight Recorder Parameter Requirements, §121.344a Listed in §121.344a(f)?
YES §121.344a(c) Appdx M 88 parameters.
YES Not required to comply with part 121.
May be required to comply with §135.152.
END NO Manufactured After 8/20/2002?
Manufactured After 8/18/2000?
YES Brought on US Register after 10/11/1991?
Foreign Registered and added to US Ops Spec after 10/11/ 1991?
NO NO Not required to carry a FDR.
§121.344a(1)(2)(3) 18* or 22** parameters listed in §121.344(a). Ranges, accuracies, and resolutions as specified in part 135 Appndx B.
YES * Either the parameter listed below must be recorded:
§121.344(a)(12) or (a)(15) §121.344(a)(13) or (a)(16) §121.344(a)(14) or (a)(17) For airplanes with more than two engines, §121.344(a)(18) must also be recorded if sufficient capacity is available on the existing recorder.
Parameters §§121.344(a)(12) through 121.344(a)(17) each may be recorded from a single source.
** Commensurate with the capacity of the recording system (FDAU or equivalent and the DFDR).
*** Commensurate with the capacity of the recording system, all additional parameters (88) listed in §121.344(a) for which information sources are installed and which are connected to the recording system.
D YES From Page 3-3 §121.344 10-19 Passenger Seats?
Less than 10 seats?
YES YES NOYES NO NO END Not required to carry a FDR NO Page 3-8 §135.152 NO
Appendix 3
Appendix 3
Appendix 3 10-19 passenger seats?
YES Brought onto US register after 10/11/1991?
YES NO Non-US registered, added to US Op Specs after 10/11/1991?
§135.152(a), Appdx B (airplane) 18 parameters or C (rotorcraft) 23 parameters Airplane with 20-30 or rotorcraft with 20 or more passenger seats?
NO YES Manufactured after 10/11/1991?
NO Type certificated after 9/30/1969?
§135.152(b)(3), Appdx D (airplane) 29 + 17 optional parameters or E (rotorcraft) 25 parameters §135.152(b)(2), 22 parameters per Appdx B (airplane) or C (rotorcraft) YES §135.152(b)(1), 11 parameters per Appdx B (airplane) or C (rotorcraft) YES Listed in §135.152(k) and manufactured before 8/18/1997?
10-30 seat airplane manufactured after 8/18/2000?
Manufactured after 8/19/2002?
NO §135.152(i), Appdx F 57 parameters §135.152(j), Appdx F 88 parameters
YES YES NO YES YES NO NO NO NO From Page 3-1, Page 3-2 §91.609, Page 3-3 §121.343, or Page 3-5 §121.344a Part 135 Flight Recorder Parameter Requirements, §135.152 D END Not required to carry an FDR
Appendix 4 APPENDIX 4. TYPICAL REASONABLENESS AND QUALITY CHECK
INSTRUCTIONS
1. GENERAL. The operator must accomplish a reasonableness and quality check of the recorded flight data to ascertain that the data is being recorded correctly and that noise and data dropouts do not interfere with the ability to interpret the recorded data. The check may be performed using data that is in electronic format or hardcopy. If a hardcopy printout is used, data traces should also be available. The check must be performed using data that has been extracted in EU because octal, BCD, or hexadecimal coded data do not provide the analyst a clear understanding of how the parameters are varying and how they are correlated to each other.
2. CHECKLIST. The analyst must use a checklist to confirm that all necessary checks have been accomplished. The checklist must refer the analyst to troubleshooting or repair procedures if a suspect parameter is identified.
3. FLIGHT SEGMENT SELECTION. The data to be used by the analyst should be extracted from both the takeoff and the landing phase of flight. During the cruise segment of a flight the parameters remain steady, and therefore movement of related parameters cannot be correlated.
The takeoff and landing segments of flight provide the analyst an opportunity to observe data that is changing as the aircraft climbs, descends, accelerates, decelerates, and banks or turns.
Furthermore, many parameters that are not exercised during the cruise segment are exercised during the takeoff and landing segments. We recommend that the analyst conduct the review of parameters over several flight segments.
4. SIGN CONVENTIONS. Each aircraft has a pre-established sign convention for the direction of movement of its flight control surfaces. It is imperative that the analyst be able to confirm proper direction of movement and not just verify movement. Therefore, the sign convention should be included in the checklist or the analyst should review the assigned sign conventions before beginning the check.
5. FAILED PARAMETERS. The analyst should examine the extracted data to determine if parameters that normally vary in flight, e.g., flight controls, flight control surface positions, and heading, are indeed varying. Values at their “maximum limit” or that are unvarying indicate an inoperative sensor or other failure. Accelerometers tend to fail at the “maximum limit” position.
If the accelerometer trace is not moving during all segments of the flight check, check to see if it indicates maximum or minimum acceleration. An accelerometer failure indicating a mid-point value is uncommon.
6. CORRELATION TO OTHER PARAMETERS. The reasonableness check should include a check of the correlation between parameters that depend upon each other. For example, if roll increases, a turn is indicated and heading should begin to change soon after the increase is detected. Also, aileron position and control wheel position should have changed immediately before the roll initiates. There may even be a variation in lateral acceleration. Again, it is important the analyst confirm that that movement is indicated in the proper direction according to the aircraft sign convention. Table 4-1 is provided as an aid to prepare a reasonableness checklist. It summarizes parameters in a 34-parameter DFDRS that may be expected to interact.
A check mark (9) in a block indicates that the parameter identified in the row and the parameter
Appendix 4 identified in the column are interdependent at some time during takeoff and climb or approach and landing. Therefore, the movement of one parameter should cause or be caused by movement in the other. The following examples show how to use Table 4-1 in developing a reasonableness checklist for each parameter.
a. Thrust Reverser Position Reasonableness and Quality Check. In Table 4-1, the column labeled Thrust Reverser Positions (number 22) contains check marks in the rows labeled Airspeed, Engine Thrust, Longitudinal Acceleration, Autopilot AFCS Mode, and Air/Ground Sensing. The normal expectation is for the thrust reverser to deploy during rollout after landing.
Thus, the following checklist might be developed using the parameters identified by a check mark.
(1) Examine the thrust reverser in-transit data and the thrust reverser deployed data to determine that they indicate in-transit only for a short period during the landing roll and deployed at the end of the in-transit period. The data should indicate in-transit and the deployed discrete should indicate stowed near the end of the landing roll.
(2) Examine the engine thrust data during the in-transit period and immediately after the deployed indication. During the in-transit period, engine thrust should have decreased to near zero. Immediately after the thrust reverser deployed indication, the engine thrust should have increased to near the maximum indication.
(3) Examine the airspeed and longitudinal thrust data. These two parameters should be decreasing during the in-transit period and should dramatically decrease immediately after the deployed indication.
(4) Examine the autopilot mode discrete and the air/ground sensing discrete. The autopilot mode discrete should indicate that the autopilot has disengaged and the air/ground sensing switch discrete should indicate that the aircraft is on the ground.
(5) Examine the remaining data for the thrust reverser discretes to ascertain that no in-transit or deployed indications appear. If intermittent indications appear, determine that they are within allowable values and do not have sufficient duration to be interpreted as an actual deployment.
b. Lateral Control Surface Position Reasonableness and Quality Check. The column labeled Lateral Control Surface Positions contains check marks in the rows labeled Heading, Roll Attitude, Lateral Control Position, and Localizer Deviation. The lateral control surfaces are typically ailerons that are used in establishing the aircraft in a turn and returning the aircraft to straight flight from a turn. The lateral control surface position data may be checked along with the lateral control position data. These checks may be accomplished during the approach and landing segment.
(1) Examine the lateral control surface position trace for deviations during the initial approach segment. A large deviation would normally indicate the aircraft turning onto final approach heading. Check that the lateral control position and roll attitude make a large change at the same time.