292 limitation should be placed in the appropriate operating manuals that prohibits the use of the FMS when operating with an alternate forward c.g. limit.
(f) All affected documents (weight and balance manuals, flight crew operating manual, etc.) should be revised to reflect the alternate forward c.g. limits. These documents should also note any restrictions associated with their use.
239. Performance Credit For Automatic Propeller Drag Reduction Devices.
a. Explanation . In the description of takeoff path requirements, § 25.111(c)(4) states, “The airplane configuration may not be changed, except for gear retraction and automatic propeller feathering…until the airplane is 400 feet above the takeoff surface.”
b. Procedures .
(1) Propeller pitch setting generally has a significant effect on minimum control speeds and airplane drag. The magnitude of these effects is such that continued safe flight may not be possible should a combined failure of an engine and its automatic propeller drag reduction system occur at a takeoff speed based on operation of that system. Consequently, in accordance with § 25.1309(b)(1), the probability of this combined failure must be shown to be extremely improbable (on the order of 10-9 per flight hour).
(2) In determining the combined engine and automatic propeller drag reduction system failure rate of paragraph (1) above, the engine failure rate should be substantiated.
Notwithstanding the in-service engine failure rate, the failure of the automatic propeller drag reduction system should be shown not to exceed 10-4 per flight hour.
(3) The automatic propeller drag reduction system should be designed so that it will automatically be disabled on the operating engine(s) following operation on the failed engine.
The probability of an unwanted operation of the automatic propeller drag reduction system on an operating engine, following its operation on the failed engine, should be shown to be extremely improbable (on the order of 10-9 per flight hour).
(4) If performance credit is given for operation of the automatic propeller drag reduction system in determining the accelerate-go takeoff distances, the propeller of the failed engine must also remain in the reduced drag position in determining the accelerate-stop distances.
(5) In determining the brake application speed for the maximum energy rejected takeoff demonstration of § 25.109(g), consideration should be given to the accelerate-stop configuration (all-engines-operating vs. engine failure with automatic propeller drag reduction system operation) that will produce the greatest brake energy absorption requirement.
(6) The limitations section of the AFM should contain a requirement for a flight crew functional check of the automatic propeller drag reduction system. The frequency with which
293 flight crew functional checks and ground maintenance checks of the automatic propeller drag reduction system are required will be considered in the evaluation of the system reliability.
(7) Clear annunciations should be provided to the flight crew for the following:
(a) The automatic propeller drag reduction system is “ARMED.”
(b) A malfunction exists in the automatic propeller drag reduction system.
240. Airplane Backing Using Reverse Thrust.
a. Explanation . Where compliance with applicable airworthiness requirements has been demonstrated, operational approval has been granted for the use of reverse thrust to back airplanes away from airport gates in lieu of a tug pushback. The applicable airworthiness requirements are prescribed in paragraph b, below. Note that compliance with these requirements only demonstrates the capability of the airplane, and does not constitute operational approval; operational approval should be coordinated with the applicable FAA Flight Standards office.
b. Procedures . To obtain airworthiness approval for reverse thrust backing, compliance should be demonstrated with the criteria prescribed below. Since operational approvals for reverse thrust backing specify the applicable airplanes, airports, and gates, some of these tests will be site specific and should be coordinated with the applicable FAA Flight Standards office.
(1) Both the airplane and engine manufacturer should determine the applicability of the maneuver and provide appropriate limitations for the procedure. These limitations should include:
(a) Engine power setting and operating parameter limits;
(b) Minimum and maximum allowable weights;
(c) Center of gravity (c.g.) limits;
(d) Ramp slope limits;
(e) Use of wheel brakes;
(f) Atmospheric conditions (see NOTE 1, below); and
(g) Any other factor unique to the proposed operation.
NOTE: 1. The use of reverse thrust backing with snow, ice, or slush on the ramp, or during periods of heavy rain, is not considered good operating practice.
(2) All limitations, and any normal or abnormal operating procedures, associated with reverse thrust backing should be included in the AFM. Any procedures related to ground crew functions should also be included in the AFM.
(3) Testing should be conducted to verify that the reverser efflux does not have a detrimental effect on the powerplant installations. Items to be considered include:
(a) Foreign object damage (FOD);
(b) Effects on engine cooling;
(c) Inlet flow distortion;
(d) Re-ingestion of exhaust gases; and
(e) Any effects on engine mounted accessories.
(4) Testing should be conducted to verify that the reverser efflux does not have a detrimental effect on other airplane systems such as air conditioning system inlets, APU inlets and exhausts, overboard drains, etc.
(5) It should be verified that cockpit and cabin air will not be contaminated.
NOTE: 2. It is acceptable to have a limitation prohibiting the operation of the air conditioning packs during reverse thrust b acking to avoid cockpit and cabin air contamination.
(6) Reverse thrust backing demonstrations should be conducted to evaluate the associated procedures. These demonstrations should be conducted at:
(a) Maximum ramp weight with the c.g. at the aft limit, and
(b) Any other weight that may be critical with the c.g. at the aft limit.
(7) The reverse thrust backing demonstrations of paragraph (6), above, should be evaluated to determine:
(a) The degree of aft pitching moment, including its effect on nose wheel steering;
(b) The effect of inadvertent heavy/emergency braking action;
(c) Adequate cockpit visibility and ground crew function;
(d) The adequacy of procedures for transitioning from reverse to forward thrust;
(e) The effect of thrust asymmetry due to failure of an engine to enter reverse, or recover forward thrust mode;
(f) The effects of low tire pressures;
(g) The effect of ramp slope and surface condition;
(h) The effects of ambient atmospheric temperature; and
(i) The effect of flap/slat configuration.
Appendix 1 A1-1 Appendix 1
Acronyms and Abbreviations
Acronym/ Definition Abbreviation
AC advisory circular ACARS aircraft communications addressing and reporting system ACO aircraft certification office ACN aircraft classification number ADC air data computer ADF automatic direction finder ADI attitude director indicator ADQ adequate AEO all-engines-operating AFM airplane flight manual AGL above ground level AHRS attitude and heading reference system AOA angle of attack A-PC airplane-pilot coupling APU auxiliary power unit ARSR air route surveillance radar ARTCC air route traffic control center ASR airport surveillance radar ATA Air Transport Association ATC air traffic control ATCRBS air traffic control radar beacon system ATS automatic throttle system ATT REF attitude reference ATTCS automatic takeoff thrust control system C Celsius CAR civil air regulations
Appendix 1 A1-2 CAS calibrated airspeed CAT category CAWS central aural warning system CBR California bearing ratio CDL configuration deviation list CDU cockpit display unit CFR Code of Federal Regulations
c.g. center of gravity CL lift coefficient CMM component maintenance manual CN yawing moment coefficient COM communications CON controllable CRT cathode ray tube CVR cockpit voice recorder CWS control wheel steering Δ incremental change in value δ ratio of atmospheric pressure at any altitude to the pressure at sea level dB decibel DFDR digital flight data recorder DG directional gyros DH decision height DME distance measuring equipment ECAM electronic centralized aircraft monitor EFCS electronic flight control system EGT exhaust gas temperature EICAS engine indicating and crew alerting system ELT emergency locator transmitter EMC electromagnetic compatibility EMI electromagnetic interference EPR engine pressure ratio
Appendix 1 A1-3 ESDU engineering sciences data unit F Fahrenheit F & R function and reliability FGS flight guidance system FMEA failure modes and effects analysis FMS flight management system FOD foreign object damage FS longitudinal control (stick) force FS/g stick force per g ft. foot or feet FWC flight warning computer g or G acceleration due to gravity at the Earth’s surface GNSS global navigation satellite system GPWS ground proximity warning system HF high frequency HGS head up guidance system HQ handling qualities HSI horizontal situation indicator HQRM handling qualities rating method HUD head up display Hz cycles per second IAS indicated airspeed ICAO International Civil Aviation Organization IKE initial kinetic energy ILS instrument landing system IMC instrument meteorological conditions INS inertial navigation system IRS inertial reference system ITT interstage turbine temperature IVSI instantaneous vertical speed indicator KE kinetic energy
Appendix 1 A1-4 LF low frequency LFE limit flight envelope LNAV lateral navigation M Mach number MAC mean aerodynamic chord MC master caution MCS master caution system MCT maximum continuous thrust MDA minimum descent altitude MEL minimum equipment list MFD multi-function display MF medium frequency Min. minutes min. minute(s) MLRC long range cruise Mach MLS microwave landing system MMEL master minimum equipment list MW master warning MWS master warning system max maximum friction coefficient available between a tire and the runway surface N1 rotational speed of low pressure compressor (turbine engine) N2 rotational speed of high pressure compressor (turbine engine) NAS national airspace system NAV navigate NM nautical mile(s) NFE normal flight envelope
Appendix 1 Change 1 A1-5 OEW operating empty weight OFE operational flight envelope PA public address PFC porous friction course PIO pilot induced oscillation Q dynamic pressure R/A radio altimeter RFI radio frequency interference
r.p.m. or RPM revolutions per minute RMI radio magnetic indicator RNAV area navigation RNP required navigation performance RTO rejected takeoff RVP Reid vapor pressure RVR runway visual range SAAAR special aircraft and aircrew authorization required SAS stability augmentation system SAT static air temperature, or satisfactory (when used with the handling qualities rating system) SATCOM satellite communications secs. seconds SELCAL selective calling system S/F slow/fast SR special regulation STC supplemental type certificate STOL short takeoff and landing SWC stall warning computer TAT total air temperature TCAS traffic collision avoidance system TIA type inspection authorization
Appendix 1 Change 1 A1-6 TIR type inspection report TOW takeoff warning system TSO technical standard order T/W thrust-to-weight ratio UNSAT Unsatisfactory or Failed V1 maximum speed in the takeoff at which the pilot must take the first action
(e.g.; apply brakes, reduce thrust, deploy speed brakes) to stop the airplane within the accelerate-stop distance. It also means the minimum speed in the takeoff, following a failure of the critical engine at VEF, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance.
V2 takeoff safety speed V2MIN minimum takeoff safety speed V35 speed at a height of 35 feet above the takeoff surface VD/MD design diving speed VDF/MDF demonstrated flight diving speed VEF speed at which the critical engine is assumed to fail during takeoff VFC/MFC maximum speed for stability characteristics VFE maximum flap extended speed VFR visual flight rules VG vertical gyros VHF very high frequency VLE maximum landing gear extended speed VLO maximum landing gear operating speed VLOF lift-off speed VMC visual meteorological conditions VMC minimum control speed with the critical engine inoperative VMCA minimum control speed in the air VMCG minimum control speed on the ground
Appendix 1 Change 1 A1-7
VMCL minimum control speed during approach and landing with all engines operating VMCL(1 out) minimum control speed during approach and landing with one engine inoperative VMCL-2 minimum control speed during approach and landing with one critical engine inoperative (for airplanes with three or more engines) VMCL-2(2 out) minimum control speed during approach and landing with two engines inoperative (for airplanes with three or more engines) VMO/MMO maximum operating limit speed VMU minimum unstick speed VNAV vertical navigation VOR very high frequency omnidirectional range VORTAC very high frequency omnidir ectional range tactical air navigation VREF reference landing speed VS stalling speed or the minimum steady flight speed at which the airplane is controllable VS0 stalling speed or the minimum steady flight speed in the landing configuration VS1 stalling speed or the minimum steady flight speed in a specific configuration VSR reference stall speed VSR0 reference stall speed in the landing configuration VSR1 reference stall speed in a specific configuration VSW speed at which the onset of natural or artificial stall warning occurs WAT weight, altitude, temperature W/δ weight/delta
Appendix 2 A2-1 Appendix 2
Function and Reliability Tests - § 21.35(b)(2)
1. Explanation.
a. In order to satisfactorily accomplish the objectives concerning additional flight tests and the extent thereof, the Administrator deems it necessary that:
(1) A comprehensive and systematic check be made, in flight, of the operation of all components to determine whether they “function properly” (i.e., perform their intended function without introducing safety hazards).
(2) Sufficient FAA test experience, and supplementary experience gained from operators’ route proving tests, should be obtained and evaluated to give reasonable assurance that the airplane is “reliable” (i.e., should continue to function properly in service).
NOTE: In order to obtain wider experience, manufacturers are encouraged to cooperate with airlines or other responsible operators in operating airplanes with provisional type certificates under service conditions.
(3) Appropriate corrective action be taken when the need therefore is determined under subparagraphs (1) and (2) of this paragraph.
2. Procedures. The principal FAA flight test pilot for the project will act as coordinator of all flight activities during the official program, and that pilot (or a designated alternate) will participate in all flights. Other FAA personnel will not board the function and reliability (F & R) airplane(s) during these activities, particularly in regard to flight plans and procedures, unless authorized by the flight test pilot. The manufacturer’s pilot should be in command of all flights, but FAA pilots will fly the airplane to determine compliance with § 21.35(b)(2). Other FAA personnel (e.g., representatives of other divisions and specialists) will participate in the flight tests, when deemed necessary, to accomplish the purpose of the tests.
a. Test Time . It is highly desirable that function and reliability test programs be administered uniformly so that the program and flight time for a given project would be approximately the same, regardless of which FAA ACO administered the project. This is difficult to achieve without establishing fixed arbitrary test times, which would obviously be contrary to the intent of § 21.35 (b)(2). The following procedure, which permits considerable flexibility, is therefore established as guidance for administering F & R test programs:
(1) For a turbine engine-powered airplane incorporating engines of a type not previously certificated, § 21.35(f)(1) requires an F & R test program of at least 300 hours. This 300 hour minimum may also be applied to a complex new airplane model (e.g., an airplane with an electronic flight control system (fly by wire)). Though some F & R test requirements can be completed concurrently with certification testing (if relevant design conformity can be shown),