ATA 63-00-00 – MAIN ROTOR DRIVE ATA Function Description Failure Condition (FC) Phase of Operation Effect of the Failure on the Aircraft, Crew and Occupants Classification of the FC Notes (assumptions) Supporting Material Verification Method 6320 Main Rotor Gearbox Provide torque and rotational speed to the rotor shaft.
Loss of lubrication to main transmission.
Cruise Aircrew workload increases substantially due to the need to conduct a landing as soon as possible.
Analysis and Test 6321 Main Rotor Brake Provide braking to the rotor Inadvertent activation of rotor braking system during flight.
ALL Continued safe flight is not guaranteed. For instance, engagement of the braking pad during high power to the main rotor could create a fire.
Analysis and Test 6340 Rotor Drive Indicating System Provide MGB chip detection Failure of chip detector system to detect and annunciate the existence of chips.
ALL Continued safe flight and landing is not guaranteed due to the degradation of gears below the required load capability.
Analysis and Test Figure AC 29 MG 21-1. Generic Examples by ATA.
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AC 29-2C, Chg 7 2/4/2016 Note: Not all ATA chapters or subchapters have been included. Also, the italicized entries are not usually included in the failure condition description but in the systems description or assumptions section.
ATA 63-00-00 – MAIN ROTOR DRIVE ATA Function Description Failure Condition (FC) Phase of Operation Effect of the Failure on the Aircraft, Crew and Occupants Classification of the FC Notes (assumptions) Supporting Material Verification Method Provide MGB Loss of oil ALL A significant reduction Analysis and oil pressure pressure in safety margins would Test indication indication. exist due to the possible delay in crew action to an actual loss of oil.
Aircrew workload increases slightly due to changing the planned flight and the monitoring of secondary indications.
Erroneous ALL A substantial reduction Analysis and annunciation in safety margins would Test of low oil exist due to the delayed pressure reaction of the crew to warning. an actual loss of oil.
Slight increase in aircrew workload due to conflicting low oil pressure warning and oil pressure indicator.
Figure AC 29 MG 21-1. Generic Examples by ATA.
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ATA 63-00-00 – MAIN ROTOR DRIVE ATA Function Description Failure Condition (FC) Phase of Operation Effect of the Failure on the Aircraft, Crew and Occupants Classification of the FC Notes (assumptions) Supporting Material Verification Method Loss of oil ALL Large reduction in the Analysis and pressure aircraft safety margin; Test indication and cannot determine if low oil adequate oil pressure is pressure present. Secondary warning. cues may be present to pilot (Increase oil temperature, vibration and noise levels, in case of actual loss of MGB oil).
Substantial increase in aircrew workload.
Misleading oil ALL Significant reduction in Analysis and pressure the aircraft safety Test indication. margin due to erroneous oil pressure indication (reads normal but actual oil pressure is low).
Substantial increase in aircrew workload.
Misleading oil ALL Continued safe flight is Analysis pressure not guaranteed due to indication and loss of all indications of loss of low oil MGB oil pressure loss pressure and ensuing gearbox warning. seizure.
Figure AC 29 MG 21-1. Generic Examples by ATA.
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AC 29-2C, Chg 7 2/4/2016 Note: Not all ATA chapters or subchapters have been included. Also, the italicized entries are not usually included in the failure condition description but in the systems description or assumptions section.
ATA 63-00-00 – MAIN ROTOR DRIVE ATA Function Description Failure Condition (FC) Phase of Operation Effect of the Failure on the Aircraft, Crew and Occupants Classification of the FC Notes (assumptions) Supporting Material Verification Method Provide Nr indication Loss of rotor RPM (Nr) indication.
ALL Slight increase in aircrew workload due to the need to monitor secondary engine instruments.
Analysis and/or Test Figure AC 29 MG 21-1. Generic Examples by ATA.
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ATA 73-00-00 - ENGINE FUEL AND CONTROL ATA Function Description Failure Condition (FC) Phase of Operation Effect of the Failure on the Aircraft, Crew and Occupants Classification of the FC Notes (assumptions) Supporting Material Verification Method 7331 Fuel Flow Indicating Loss of fuel flow.
ALL The reduction in safety margins and functional capability in the system may prohibit continued safe flight and landing.
Analysis Malfunction and loss of fuel flow indication.
ALL The failure can delay crew action long enough to prevent continued safe flight and landing.
Analysis Misleading fuel flow alert failed.
ALL A large reduction in safety margins or functional capabilities.
Analysis 7332 Fuel Pressure Indicating Loss of fuel pressure.
ALL The reduction in safety margins and functional capability in the system may prohibit continued safe flight and landing.
Analysis Malfunction and loss of fuel pressure indication.
ALL A combination of a malfunction with a loss of indication in the system can delay crew action long enough causing a large reduction in safety margins or functional capabilities.
Analysis and Test Figure AC 29 MG 21-1. Generic Examples by ATA.
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AC 29-2C, Chg 7 2/4/2016 Note: Not all ATA chapters or subchapters have been included. Also, the italicized entries are not usually included in the failure condition description but in the systems description or assumptions section.
ATA 73-00-00 - ENGINE FUEL AND CONTROL ATA Function Description Failure Condition (FC) Phase of Operation Effect of the Failure on the Aircraft, Crew and Occupants Classification of the FC Notes (assumptions) Supporting Material Verification Method Misleading fuel pressure indication.
ALL If the indication to the pilot is a warning, the likely requirement is to land immediately.
Worst case is ditching in poor conditions causing a large reduction in safety margins or functional capabilities.
Analysis Figure AC 29 MG 21-1. Generic Examples by ATA.
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ATA 75-00-00 - AIR ATA Function Description Failure Condition (FC) Phase of Operation Effect of the Failure on the Aircraft, Crew and Occupants Classification of the FC Notes (assumptions) Supporting Material Verification Method 7510 Engine Anti- Icing (A/I) System Loss of a single engine A/I system on a multi-engine aircraft.
Cruise A significant loss of safety margin due to loss of a critical redundant system.
Significant increase in pilot workload.
Analysis and Test Loss of engine A/I system on a single engine aircraft.
Cruise Results in a large reduction in aircraft safety margin and a large increase in pilot workload.
Analysis and Test 7532 Compressor Bleed Valve Malfunction valve is failed OPEN on one engine of a multi-engine aircraft.
Cruise May cause an engine stall or surge that leads loss of one engine.
Significant increase in pilot workload.
Analysis and Test Malfunction valve is failed OPEN on one engine on a single engine aircraft.
Cruise May cause an engine stall or surge that leads loss of the engine.
More than a significant increase in pilot workload as the crew will likely have to land as soon as possible.
Analysis and Test Figure AC 29 MG 21-1. Generic Examples by ATA.
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AC 29-2C, Chg 7 2/4/2016 Note: Not all ATA chapters or subchapters have been included. Also, the italicized entries are not usually included in the fail ure condition description but in the systems description or assumptions section.
ATA 75-00-00 - AIR ATA Function Description Failure Condition (FC) Phase of Operation Effect of the Failure on the Aircraft, Crew and Occupants Classification of the FC Notes (assumptions) Supporting Material Verification Method 7540 Bleed Air Indicating System Loss of bleed air indication.
ALL A slight reduction in safety margins.
A slight increase in pilot workload.
Analysis and Test Misleading bleed air indication.
ALL Misleading indication may cause an inappropriate engine setting resulting in a significant reduction in system safety margins.
Analysis and Test Figure AC 29 MG 21-1. Generic Examples by ATA.
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ATA 79-00-00 – OIL ATA Function Description Failure Condition (FC) Phase of Operation Effect of the Failure on the Aircraft, Crew and Occupants Classification of the FC Notes (assumptions) Supporting Material Verification Method 7931 Engine Oil Pressure Loss of oil press indication.
ALL Loss of indication can delay crew action long enough to prevent continued safe flight and landing.
Analysis Misleading oil press indication.
ALL If the indication to the pilot is a warning, the likely requirement is to land immediately.
Worst case is ditching in poor conditions causing a large reduction in safety margins or functional capabilities.
Analysis and Test 7932 Engine Oil Quantity Loss of oil quantity indication.
ALL Loss of indication is considered to be a significant increase to pilot workload but only when required to be displayed per 14 CFR
29.1337(d)(2).
Analysis Figure AC 29 MG 21-1. Generic Examples by ATA.
Page MG 21 - 43
AC 29-2C, Chg 7 2/4/2016 Note: Not all ATA chapters or subchapters have been included. Also, the italicized entries are not usually included in the failure condition description but in the systems description or assumptions section.
ATA 79-00-00 – OIL ATA Function Description Failure Condition (FC) Phase of Operation Effect of the Failure on the Aircraft, Crew and Occupants Classification of the FC Notes (assumptions) Supporting Material Verification Method Misleading oil quantity indication.
ALL If the indication to the pilot is a warning, the likely pilot action is to land immediately.
Worst case is ditching in poor conditions causing a large reduction in safety margins or functional capabilities.
Analysis and Test 7933 Engine Oil Temperature Loss of oil temperature indication.
ALL Loss of indication in the system can delay crew action long enough to cause a large reduction in safety margins or functional capabilities.
Analysis and Test Misleading oil temperature indication.
ALL If the indication to the pilot is a warning, the likely requirement is to land immediately.
Worst case is ditching in poor conditions causing a large reduction in safety margins or functional capabilities.
Analysis and Test Figure AC 29 MG 21-1. Generic Examples by ATA.
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CHAPTER 3
AIRWORTHINESS STANDARDS
TRANSPORT CATEGORY ROTORCRAFT
MISCELLANEOUS GUIDANCE (MG) AC 29 MG 22 ROTORCRAFT ONE ENGINE INOPERATIVE (OEI) TRAINING MODE.
a. Purpose. This guidance provides a means to achieve airworthiness approval for OEI training mode to be installed on rotorcraft. These devices have been mainly designed to allow category A training without using the OEI ratings thus eliminating the need of extra maintenance for the engines and drive system. This guidance does not change the regulatory requirements and does not authorize changes in, or deviations from, regulatory requirements. These guidelines are developed for category A rotorcraft. If an applicant would like to develop such a system for category B rotorcraft, additional requirements may be applied by the certification authority.
b. References and Related Documents.
(1) 14 CFR parts 21, 29, 33, and corresponding European Requirements (Certification Specifications) part 21, CS-29, CS-E.
(2) AC 29-2C.
c. Background. Different types of OEI training modes and similar systems have been developed and are likely to be developed in the future. Their intent was to provide operators with a means to simulate OEI conditions for training purposes without using the engine and drive system OEI ratings. This type of installation requires an appropriate level of qualification, commensurate to the criticality of the most severe effects on the rotorcraft.
d. Definitions. OEI Training mode: for the purpose of this guidance material, a system or device designed to train the flightcrew by simulating, with an appropriate weight, the OEI conditions, reducing the power of the engines without accessing the actual OEI engine and drive system ratings. This includes cockpit controls and display indications necessary for the flightcrew to safely operate the system or device.
e. Certification Approach. There are different basic aspects to consider when approaching an OEI Training Mode that should be addressed in the proposed certification plan.
(1) System purpose definition. The cert ification process should begin with a clear declaration of the objective of the OEI training mode. Past experiences have shown that these type of systems have been mainly designed to allow operators to train their flightcrew on category A procedures without cutting one engine to idle through the Page MG 22 - 1
AC 29-2C, Chg 4 5/1/2014
engine controls; however, the purpose could also be extended to simulate an engine failure during other conditions (i.e., failure during the cruise). In any case, the maneuver to be simulated with its initial and final points has to be clearly identified by the applicant in order to prepare the certification plan.
(2) Functional Hazard Assessment.
(i) The purpose of the system is the input for the hazard assessment where all the potential failures are identified and appropriately classified taking into account the most critical phase of flight, thus establishing in a systematic way the integrity levels required for each function provided. It is to be noted that an OEI Training Mode is designed to increase the level of safety relative to traditional training operations and therefore the design of the systems should be such that the associated functional failures are never more severe than those associated to an engine cut intentionally to idle. It should be recognized, however, that operation in training mode is an intentional operation in a degraded condition and that the consequences of certain failures may be more severe than those expected in normal operation.
(ii) The functional hazard assessment has to take into account the other systems that interact with the OEI Training Mode (typically the engine control system and the cockpit displays) and all the potential failures that can occur during operation of the training mode. The effect of engine failures and malfunctions that are likely to occur during the operation of the system need to be taken into account. The functional hazard assessment should also cover the failure associated with the safety devices introduced in the system.
(3) Engine failures. Actual engine fa ilure while in OEI training mode should be addressed. While recognizing that an actual failure during training mode is potentially more severe than one during normal operation, adequate safety devices should be provided to minimize the consequences of actual engine failure during training mode.
(4) Display of powerplant instruments. There may be different ways to present the engine data during the OEI training mode functioning. Past experience has shown that some applicants have developed systems where during the simulation, engine limits and associated cautions and warnings are re-scaled in order to present to the flightcrew the same scenario that would occur in case of an actual engine failure. As the current part 29 requirements (including § 29.1305) do not allow displaying biased parameters, the applicant should show an equivalent level of safety with respect to §§ 29.1305 and 29.1549. In particular, while the training mode is engaged, the pilot being trained should be provided with a set of information related to the training drill and not be confused by other data; the safety pilot or instructor should be informed of any abnormal conditions. If a rotor droop is gen erated during the training maneuver, it is acceptable that the NR indicator shows the limits relevant to OEI conditions even if both engines are running.
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