Appendix 4 A4-58
(5) The consumption of fuel and oil after the engines are assumed to fail shall be that which is accounted for in the net flight path data shown in the AFM.
40T.84 Landing limitations.
(a) Airport of destination. No airplane shall be taken off at a weight in excess of that which, in accordance with the landing distances shown in the AFM for the elevation of the airport of intended destination and for the wind conditions anticipated there at the time of landing, would permit the airplane to be brought to rest at the airport of intended destination within 60 percent of the effective length of the runway from a point 50 feet directly above the intersection of the obstruction clearance plane and the runway. The weight of the airplane shall be assumed to be reduced by the weight of the fuel and oil expected to be consumed in flight to the airport of intended destination. Compliance shall be shown with the conditions of subparagraphs (1) and (2) of this paragraph. (See secs. 4T.123(b) and 4T.743(b).)
(1) It shall be assumed that the airplane is landed on the most favorable runway and direction in still air.
(2) It shall be assumed that the airplane is landed on the most suitable runway considering the probable wind velocity and direction and taking due account of the ground handling characteristics of the airplane and of other conditions (i.e., landing aids, terrain, etc.).
If full compliance with the provisions of this subparagraph is not shown, the airplane may be taken off if an alternate airport is designated which permits compliance with paragraph (b) of this section.
(b) Alternate airport. No airport shall be designated as an alternate airport in a dispatch release unless the airplane at the weight anticipated at the time of arrival at such airport can comply with the provisions of paragraph (a) of this section, provided that the airplane can be brought to rest within 70 percent of the effective length of the runway.
Appendix 4 A4-59
In lieu of section 43.11 of part 43 of the Civil Air Regulations the following shall be applicable.
43T.11 Transport category airplane weight limitations. The performance data in the AFM shall be applied in determining compliance with the following provisions:
(a) No airplane shall be taken off at a wei ght which exceeds the takeoff weight specified in the AFM for the elevation of the airport and for the ambient temperature existing at the time of the takeoff. (See secs. 4T.123(a)(1) and 4T.743(a).)
(b) No airplane shall be taken off at a weight such that, allowing for normal consumption of fuel and oil in flight to the airport of destination and to the alternate airports, the weight on arrival will exceed the landing weight specified in the AFM for the elevation of each of the airports involved and for the ambient temperatures anticipated at the time of landing. (See secs.
4T.123(a) (2) and 4T.743(a).)
(c) No airplane shall be taken off at a weight which exceeds the weight at which, in accordance with the minimum distances for takeoff scheduled in the AFM, compliance with subparagraphs (1) through (3) of this paragraph is shown. These distances shall correspond with the elevation of the airport, the runway to be used, the effective runway gradient, and the ambient temperature and wind component existing at the time of takeoff. (See secs.
4T.123(a)(3) and 4T.734(a).)
(1) The accelerate-stop distance shall not be greater than the length of the runway plus the length of the stopway if present.
(2) The takeoff distance shall not be greater than the length of the runway plus the length of the clearway if present, except that the length of the clearway shall not be greater than one-half of the length of the runway.
(3) The takeoff run shall not be greater than the length of the runway.
(d) No airplane shall be operated outside the operational limits specified in the AFM. (See secs. 4T.123(a) (4) and 4T.743(a).)
5. The following definitions shall apply:
(a) Clearway. A clearway is an area beyond the runway, not less than 500 feet wide, centrally located about the extended centerline of the runway, and under the control of the airport authorities. The clearway is expressed in terms of a clearway plane, extending from the end of the runway with an upward slope not exceeding 1.25 percent, above which no object nor any portion of the terrain protrudes, except that threshold lights may protrude above the plane if their height above the end of the runway is not greater than 26 inches and if they are located to each side of the runway.
Appendix 4 A4-60 NOTE: For the purpose of establishing takeoff distances and takeoff runs, in accordance with section 4T.117 of this regulation, the clearway plane is considered to be the takeoff surface.
(b) Stopway. A stopway is an area beyond the runway, not less in width than the width of the runway, centrally located about the extended centerline of the runway, and designated by the airport authorities for use in decelerating the airplane during an aborted takeoff: To be considered as such, a stopway must be capable of supporting the airplane during an aborted takeoff without inducing structural damage to the airplane. (See also sec. 4T.115(d) of this regulation.)
Appendix 5 A5-1
Appendix 5
Historical Development Of Accelerate-Stop Time Delays
1. Explanation.
a. As the rules pertaining to transport category airplane accelerate-stop distances have developed over the years, the interpretation of those rules, with regard to pilot actions, recognition times, and delay times, has also changed. The paragraphs below provide a historical perspective on the application of pilot recognition and delay times, with references to the applicable part 25 amendment number.
b. In accordance with § 21.101 (a) and (b), the certification basis for a derivative airplane type may be the regulations specified in the type certificate of the basic airplane, depending upon the extent and nature of the changes to the airplane. For those cases where the original certification basis can be retained, the guidance presented in paragraphs 2a and b., below, may be used to show compliance with the appropriate regulations. (For more information related to determining a derivative airplane’s certification basis, see AC 21.101-1, Change 1, “Establishing the Certification Basis of Changed Aeronautical Products.”)
c. Regardless of the certification basis, the effects of brake wear state on energy absorption capability and stopping performance must be addressed in order to comply with § 21.21(b)(2).
The responsible FAA ACO should be contacted to establish the applicable brake wear criteria for a specific airplane type.
2. Procedures.
a. Pre-amendment 25-42 Accelerate-Stop Time Delays . Parts 1 and 25 of Title 14 of the CFR, prior to amendments 1-29 and 25-42, respectively, defined V1 as the critical engine failure speed. When this definition of V1 was applied to the accelerate-stop criteria of § 25.109 and the V1 criteria of § 25.107(a)(2), the implication was that engine failure and engine failure recognition could occur simultaneously. It was recognized that this simultaneous occurrence could not be achieved in actual operations, and that defining V1 as the engine failure speed resulted in a conflict with § 25.101(h), which requires allowance for time delays in execution of procedures. In order to resolve this conflict, V1 was applied as the engine failure recognition speed, and appropriate time delays were developed for showing compliance with § 25.101(h).
Figure 1 shows a pictorial representation of the accelerate-stop time delays that were considered acceptable for compliance with § 25.101(h) before amendment 25-42 (effective March 1, 1978).
Paragraph 2a(7) of this appendix provides guidance on reflecting these time delays in the AFM accelerate-stop distances.
Appendix 5 A5-2
Figure 1. Accelerate-Stop Time Delays
(Pre-amendment 25-42)
(1) trec = engine failure recognition time. The demonstrated time from engine failure to pilot activation of the first deceleration device, this action indicating recognition of the engine failure. For AFM data expansion purposes, in order to provide a recognition time increment that can be executed consistently in service, it has been found practical to use the demonstrated time or 1 second, whichever is greater. If the airplane incorporates an engine failure warning light, the recognition time includes the time increment necessary for the engine to spool down to the point of warning light activation, plus the time increment from light “on” to pilot action indicating recognition of engine failure.
(2) ta1 = the demonstrated time interval between activation of the first and second deceleration devices.
(3) ta2 = the demonstrated time interval between activation of the second and third deceleration devices.
(4) t = a 1-second reaction time delay to account for in-service variations. If a command is required for another crewmember to actuate a deceleration device, a 2-second delay, in lieu of the 1-second delay, should be applied for each action. For automatic deceleration devices that are approved for performance credit for AFM data expansion, established times determined during certification testing may be used without the application of the additional time delays required by this paragraph.
(5) The sequence for activation of deceleration devices may be selected by the applicant in accordance with § 25.101(f). If, on occasion, the desired sequence is not achieved during testing, the test need not be repeated; however, sufficient tests should be conducted to establish acceptable values of ta.
Appendix 5 A5-3
(6) If additional devices are used to decelerate the airplane, their respective demonstrated times, plus any additional required time delays, should be included until the airplane is in the full braking configuration.
(7) For the purpose of flight manual calculations, the 1-second delay for each action may be added at the end of the total demonstrated time. Regardless of the manner in which the time delays are applied, the flight manual calculations should assume the airplane does not decelerate during the delay time increments.
b. Amendment 25-42 thru amendment 25-91, Accelerate-Stop Time Delays . Amendment 25-42, effective March 1, 1978, introduced several new requirements affecting accelerate-stop distance determination. One of the most significant changes of amendment 25-42 was the requirement to determine an all-engines-operating accelerate-stop distance to account for the many rejected takeoffs that were not the result of an engine failure. Amendment 25-42 also introduced into the regulations an engine-failure speed, VEF; redefined the takeoff decision speed, V1; revised the accelerate-stop distance criteria to correspond to the VEF and V1 definitions; and added a 2-second time delay between V1 and the first action to decelerate the airplane during which the airplane continues accelerating with the operating engines at takeoff thrust. Figure 2 shows a pictorial representation of the accelerate-stop time delays in accordance with the provisions of part 25, including amendment 25-42:
Appendix 5 A5-4
Figure 2. Accelerate-Stop Time Delays
(Amendment 25-42 thru amendment 25-91)
(1) trec - § 25.107 defines the relationship between VEF and V1 as follows:
“VEF is the calibrated airspeed at which the critical engine is assumed to fail. VEF must be selected by the applicant, but may not be less than VMCG determined under § 25.149(e). V1, in terms of calibrated airspeed, is the takeoff decision speed selected by the applicant;
however, V1 may not be less than VEF plus the speed gained with the critical engine inoperative during the time interval between the instant at which the critical engine is failed, and the instant at which the pilot recognizes and reacts to the engine failure, as indicated by the pilot’s application of the first retarding means during accelerate-stop tests.”
(2) Demonstrated engine failure recognition times less than 1 second should be carefully reviewed to assure the conditions under which they were obtained were representative of that which may reasonably be expected to occur in service. A sufficient number of demonstrations should be conducted using both applicant and FAA test pilots to assure that the time increment is representative and repeatable. The pilot’s feet should be on the rudder pedals, not brakes, during demonstration tests.
Appendix 5 A5-5
(3) ta1 = the demonstrated time interval between activation of the first and second deceleration devices.
(4) ta2 = the demonstrated time interval between activation of the second and third deceleration devices.
(5) If a command is required for another crewmember to activate a deceleration device, a 1-second delay, in addition to the delays specified in paragraphs (3) and (4) above, should be applied for each action. For automatic deceleration devices which are approved for performance credit for AFM data expansion, established system times determined during certification testing may be used. These established times cannot be assumed to start until after the pilot action that triggers them; that is, they cannot be triggered before the first pilot action and, hence, cannot begin until at least 2 seconds after V1.
(6) The sequence for activation of deceleration devices may be selected by the applicant in accordance with § 25.101(f). If, on occasion, the desired sequence is not achieved during testing, the test need not be repeated; however, sufficient tests should be conducted to establish acceptable values of ta.
(7) Figure 2 shows a pictorial representation of how to apply time delays with up to three deceleration devices. If more than three devices are used to decelerate the airplane, the respective demonstrated time plus a 1-second reaction time delay should be included for each device beyond that represented pictorially in figure 2 until the airplane is in the full braking configuration.
Appendix 6 A6-1
Appendix 6
FAA Handling Qualities Rating Method
1. Explanation. With the advent of transport category airplanes employing electronic flight control systems (EFCS) that provide control augmentation, and sometimes employ limiting systems, the ability to make a literal finding of compliance with many of the stability and control requirements of part 25 was eroded. As a result, the HQRM presented in this appendix was developed to provide a pseudo-quantitative means of evaluating airplane flying qualities. The HQRM draws on a matrix of parameters in defining the desired handling characteristics, including atmospheric conditions, flight envelope conditions, pilot task tracking requirements, and probability of occurrence.
a. Figure 1 presents a list of deficiencies that exist for applying existing regulations to airplanes with maneuver-demand electronic flight control systems.
b. Since the subject airplanes have redundant EFCS capabilities, which generally provide reduced levels of control duplication with progressive failure states, a “failure consequence vs.
probability” type of approach is applicable (see figure 2).
2. Procedures. The HQRM is to be applied as a task-oriented system to be used in the evaluation of airplane handling qualities in accordance with the following procedures. See figure 3, development of FAA HQRM criteria.
a. A probability of occurrence versus effect philosophy is applied in relating the flight test variables to flight envelope characteristics, atmospheric disturbance levels, and probability of a specific flight control failure state. The combined application of these parameters to make a finding of compliance is shown schematically in figure 4.
b. It has also become necessary to create a defined set of criteria by which to evaluate the handling qualities of EFCS-equipped airplanes. In an attempt to create a system that can be used in a standardized manner, the handling qualities rating method has been limited to three levels:
Satisfactory (SAT), Adequate (ADQ), and Controllable (CON). These pilot ratings are defined and compared with other established rating scales in figure 5A. Handling qualities should be demonstrated to meet one of these rating levels for a particular flight condition that will be defined in terms of probability of occurrence, flight envelope, and level of atmospheric disturbance (see figures 5B, C, and D).
c. Matrices can be formed of measurable flight parameters for the normal, operational, and limit flight envelopes. These are shown in the “spider web” charts for flaps up and flaps down in figures 6 and 7, respectively.
d. A description of the pilot ratings (SAT, ADQ, and CON) is presented in figure 8, along with the equivalent Cooper-Harper and Military Standard ratings for comparison.
Appendix 6 A6-2
e. Figure 9 presents the method for combining the various flight condition parameter probabilities that will, in turn, be used to determine the minimum handling qualities rating. This method is shown in a graphical format in figure 10.
f. The HQRM is to be used in a task-oriented environment to evaluate airplane handling qualities while performing typical static and dynamic maneuvers. A sample list of such tasks is presented in figure 11.
g. Figure 12 shows a table of the minimum FAA handling qualities rating for a given flight condition, defined as a combination of the flight envelope conditions and the level of atmospheric disturbance, relative to the probability of the failure condition being evaluated.
Figure 1. Airworthiness HQ Regulations Impacted/Outpaced by Technology
CURRENT
REGULATION
BASIC OBJECTIVE LIKELY DEFICIENCY FOR
AIRPLANE WITH FBW
MANEUVER DEMAND EFCS
25.171/173/175 Static Long. Stab:
1 lb/6 kts. average Literal noncompliance: Airplane has short-term path stability
25.171/177 Stat. Lat-Dir Stab:
Fa/Beta > 0 Literal noncompliance for roll-rate command EFCS, when airplane in steady sideslip
25.671(c)(2) Control Systems. General:
Continued safe flight and landing after combination of failures not shown to be extremely improbable.
Proper objective, but no structured approach showing compliance for matrix of EFCS failure modes and flight conditions.
25.672(c)(1)-(3) Various HQ requirements for failure of stability augmentation/poweroperated systems.
Deals only with single failures (e.g., Yaw Damper-only technology) Presumes controllability and maneuverability requirements can be maintained, yet trim, stability, and stall characteristics can be impaired.
25.1309(b)(1) Occurrence of any failure condition which would prevent continued safe flight and landing is extremely improbable Applies to systems, but has indirect relation to flight characteristics evaluation-clarification needed Differences between U.S. and European airworthiness interpretations
Appendix 6 A6-3
Figure 2. Probability vs. Consequence Graph
Consequences of Failure Condition Catastrophic Accident Abnormal Procedures Probability of Failure Condition Adverse Effects on Occupants Airplane Damage Emergency Procedures Nuisance Normal
UNACCEPTABLE
ACCEPTABLE Probable Improbable Extremely Improbable
*From AC 25.1309-1A (Sys. Design & Anal.)
Appendix 6 A6-4
Figure 3. Development of FAA HQRM Criteria
Certification Program Need:
A320 MD-11 B777 1988/89 1989/90 1995/96 Existing FAA Contract Research Informal Contacts NA SA Dry den AFFTC AFWAL
MIL SPEC/STD Rating Methods & Elements Cooper-Harper Rating Method Society/Industry Documents
FA A HA NDLING QUA LITIES RA TING METHOD (Current Special Conditions, Issue Papers, & Certification Review Items)
Figure 4. Major Elements of Task-Oriented Handling Qualities Rating Method