979 - 981. [RESERVED]
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Section 6. PERSONNEL AND CARGO ACCOMMODATIONS
982. SECTION 25.771 - PILOT COMPARTMENT.
a. Rule Text.
(a) Each pilot compartment and its equipment must allow the minimum flight crew (established under § 25.1523) to perform their duties without unreasonable concentration or fatigue.
(b) The primary controls listed in § 25.779(a), excluding cables and control rods, must be located with respect to the propellers so that no member of the minimum flight crew (established under § 25.1523), or part of the controls, lies in the region between the plane of rotation of any inboard propeller and the surface generated by a line passing through the center of the propeller hub making an angle of five degrees forward or aft of the plane of rotation of the propeller.
(c) If provision is made for a second pilot, the airplane must be controllable with equal safety from either pilot seat.
(d) The pilot compartment must be constructed so that, when flying in rain or snow, it will not leak in a manner that will distract the crew or harm the structure.
(e) Vibration and noise characteristics of cockpit equipment may not interfere with safe operation of the airplane.
[Amdt. 25-4, 30 FR 6113, Apr. 30, 1965] NOTE: There is no guidance currently available on this subject.
983 - 988. [RESERVED]
989. SECTION 25.772 - PILOT COMPARTMENT DOORS.
a. Rule Text.
For an airplane that has a maximum passenger seating configuration of more than 20 seats and that has a lockable door installed between the pilot compartment and the passenger compartment:
(a) The emergency exit configuration must be designed so that neither crewmembers nor passengers need use that door in order to reach the emergency exits provided for them; and 1143
b) Means must be provided to enable flight crewmembers to directly enter the passenger compartment from the pilot compartment if the cockpit door becomes jammed.
[Amdt. 25-23, 35 FR 5676, Apr. 8, 1970; Amdt. 25-47, 44 FR 61325, Oct. 25, 1979; Amdt. 25-72, 55 FR 29782, July 20, 1990] NOTE: Refer to Advisory Circular (AC) 25-17, Transport Airplane Cabin Interiors Crashworthiness Handbook, for guidance information for showing compliance with the crashworthiness requirements of part 25 for transport category airplanes.
990 - 996. [RESERVED]
997. SECTION 25.773 - PILOT COMPARTMENT VIEW.
a. Rule Text.
(a) Nonprecipitation conditions. For nonprecipitation conditions, the following apply:
(1) Each pilot compartment must be arranged to give the pilots a sufficiently extensive, clear, and undistorted view, to enable them to safely perform any maneuvers within the operating limitations of the airplane, including taxiing, takeoff, approach, and landing.
(2) Each pilot compartment must be free of glare and reflection that could interfere with the normal duties of the minimum flight crew (established under § 25.1523). This must be shown in day and night flight tests under nonprecipitation conditions.
(b) Precipitation conditions. For precipitation conditions, the following apply:
(1) The airplane must have a means to maintain a clear portion of the windshield, during precipitation conditions, sufficient for both pilots to have a sufficiently extensive view along the flight path in normal flight attitudes of the airplane.
This means must be designed to function, without continuous attention on the part of the crew, in -
(i) Heavy rain at speeds up to 1.6 VS1 with lift and drag devices retracted; and
(ii) The icing conditions specified in § 25.1419 if certification with ice protection provisions is requested.
(2) The first pilot must have -
(i) A window that is openable under the conditions prescribed in paragraph
(b)(1) of this section when the cabin is not pressurized, provides the view specified in that paragraph, and gives sufficient protection from the elements against impairment of the pilot's vision; or 1144
(ii) An alternate means to maintain a clear view under the conditions specified in paragraph (b)(1) of this section, considering the probable damage due to a severe hail encounter.
(c) Internal windshield and window fogging. The airplane must have a means to prevent fogging of the internal portions of the windshield and window panels over an area which would provide the visibility specified in paragraph (a) of this section under all internal and external ambient conditions, including precipitation conditions, in which the airplane is intended to be operated.
(d) Fixed markers or other guides must be installed at each pilot station to enable the pilots to position themselves in their seats for an optimum combination of outside visibility and instrument scan. If lighted markers or guides are used they must comply with the requirements specified in § 25.1381.
[Amdt. 25-23, 35 FR 5676, Apr. 8, 1970; Amdt. 25-46, 43 FR 50595, Oct. 30, 1978; Amdt. 25-72, 55 FR 29778, Jul. 20, 1990] NOTE: Refer to Advisory Circular (AC) 25-7A, Flight Test Guide for Certification of Transport Category Airplanes, for guidance.
998 - 1003. [RESERVED] 1004. SECTION 25.775 - WINDSHIELDS AND WINDOWS.
a. Rule Text.
(a) Internal panes must be made of nonsplintering material.
(b) Windshield panes directly in front of the pilots in the normal conduct of their duties, and the supporting structures for these panes, must withstand, without penetration, the impact of a four-pound bird when the velocity of the airplane (relative to the bird along the airplane's flight path) is equal to the value of VC, at sea level, selected under § 25.335(a).
(c) Unless it can be shown by analysis or tests that the probability of occurrence of a critical windshield fragmentation condition is of a low order, the airplane must have a means to minimize the danger to the pilots from flying windshield fragments due to bird impact. This must be shown for each transparent pane in the cockpit that -
(1) Appears in the front view of the airplane;
(2) Is inclined 15 degrees or more to the longitudinal axis of the airplane; and
(3) Has any part of the pane located where its fragmentation will constitute a hazard to the pilots.
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(d) The design of windshields and windows in pressurized airplanes must be based on factors peculiar to high altitude operation, including the effects of continuous and cyclic pressurization loadings, the inherent characteristics of the material used, and the effects of temperatures and temperature differentials. The windshield and window panels must be capable of withstanding the maximum cabin pressure differential loads combined with critical aerodynamic pressure and temperature effects after any single failure in the installation or associated systems. It may be assumed that, after a single failure that is obvious to the flight crew (established under § 25.1523), the cabin pressure differential is reduced from the maximum, in accordance with appropriate operating limitations, to allow continued safe flight of the airplane with a cabin pressure altitude of not more than 15,000 feet.
(e) The windshield panels in front of the pilots must be arranged so that, assuming the loss of vision through any one panel, one or more panels remain available for use by a pilot seated at a pilot station to permit continued safe flight and landing.
[Amdt. 25-23, 35 FR 5676, Apr. 8, 1970; Amdt. 25-38, 41 FR 55466, Dec. 20.
1976]
b. Intent of Rule. The purpose of this rule is to ensure structural integrity of the windshield under all likely operating conditions, and to minimize the hazard to the pilots from glass fragments due to bird impact.
c. Background. This rule was carried forward from § 4b.352 of the Civil Air Regulations (CAR).
The requirement to consider the loss of vision through any one panel in front of the pilots was added by Amendment. 25-38.
d. Acceptable Compliance Methods. For guidance on compliance with this requirement, refer to the preamble of Amendment 25-23, 35 FR 5676, April 8, 1970; and Amendment 25-38, 41 FR 55466, December 20, 1976. Compliance with this requirement may be shown by test(s) such as: (1) bird impact tests with the windshield installed in a representative windshield support frame, and (2) fail safe pressure testing on the windshield.
e. References. None.
1005 - 1015. [RESERVED] 1016. SECTION 25.777 - COCKPIT CONTROLS.
a. Rule Text.
1146
(a) Each cockpit control must be located to provide convenient operation and to prevent confusion and inadvertent operation.
(b) The direction of movement of cockpit controls must meet the requirements of § 25.779. Wherever practicable, the sense of motion involved in the operation of other controls must correspond to the sense of the effect of the operation upon the airplane or upon the part operated. Controls of a variable nature using a rotary motion must move clockwise from the off position, through an increasing range, to the full on position.
(c) The controls must be located and arranged, with respect to the pilots' seats, so that there is full and unrestricted movement of each control without interference from the cockpit structure or the clothing of the minimum flight crew (established under § 25.1523) when any member of this flight crew, from 5'2" to 6'3" in height, is seated with the seat belt and shoulder harness (if provided) fastened.
(d) Identical powerplant controls for each engine must be located to prevent confusion as to the engines they control.
(e) Wing flap controls and other auxiliary lift device controls must be located on top of the pedestal, aft of the throttles, centrally or to the right of the pedestal centerline, and not less than 10 inches aft of the landing gear control.
(f) The landing gear control must be located forward of the throttles and must be operable by each pilot when seated with seat belt and shoulder harness (if provided) fastened.
(g) Control knobs must be shaped in accordance with § 25.781. In addition, the knobs must be of the same color, and this color must contrast with the color of control knobs for other purposes and the surrounding cockpit.
(h) If a flight engineer is required as part of the minimum flight crew (established under § 25.1523), the airplane must have a flight engineer station located and arranged so that the flight crewmembers can perform their functions efficiently and without interfering with each other.
[Amdt. 25-46, 43 FR 50596, Oct. 30, 1978] NOTE: There is no guidance currently available on this subject.
1017 - 1022. [RESERVED] 1023. SECTION 25.779 - MOTION AND EFFECT OF COCKPIT CONTROLS.
a. Rule Text.
1147
Cockpit controls must be designed so that they operate in accordance with the following movement and actuation:
1148
(a) Aerodynamic controls:
(1) Primary.
Controls Motion and effect Aileron Right (clockwise) for right wing down.
Elevator Rearward for nose up.
Rudder Right pedal forward for nose right.
(2) Secondary.
Controls Motion and effect Flaps (or auxiliary Forward for flaps up; rearward for lift devices) for flaps down.
Trim tabs (or Rotate to produce similar rotation of the air equivalent) plane about an axis parallel to the axis of the control.
(b) Powerplant and auxiliary controls:
(1) Powerplant.
Controls Motion and effect Power or thrust Forward to increase forward thrust and rear ward to increase rearward thrust.
Propellers Forward to increase rpm.
Mixture Forward or upward for rich.
Carburetor air heat Forward or upward for cold.
Supercharger Forward or upward for low blower.
For turbosuperchargers, forward, upward, or clockwise, to increase pressure.
(2) Auxiliary.
Controls Motion and effect
Landing gear Down to extend.
[Amdt. 25-72, 55 FR 29778, Jul. 20, 1990] NOTE: There is no guidance currently available on this subject.
1024 - 1029. [RESERVED] 1149
1030. SECTION 25.781 COCKPIT CONTROL KNOB SHAPE.
a. Rule Text.
Cockpit control knobs must conform to the general shapes (but not necessarily the exact sizes or specific proportions) in the following figure:
(See the published Code of Federal Regulations (CFR) rules for drawings of cockpit control knobs.)
[Amdt. 25-72, 55 FR 29779, July 20, 1990] NOTE: There is no guidance currently available on this subject.
1031 - 1037. [RESERVED] 1038. SECTION 25.783 - DOORS.
a. Rule Text.
(a) Each cabin must have at least one easily accessible external door.
(b) There must be a means to lock and safeguard each external door against opening in flight (either inadvertently by persons or as a result of mechanical failure or failure of a single structural element either during or after closure).
Each external door must be openable from both the inside and the outside, even though persons may be crowded against the door on the inside of the airplane.
Inward opening doors may be used if there are means to prevent occupants from crowding against the door to an extent that would interfere with the opening of the door. The means of opening must be simple and obvious and must be arranged and marked so that it can be readily located and operated, even in darkness. Auxiliary locking devices may be used.
(c) Each external door must be reasonably free from jamming as a result of fuselage deformation in a minor crash.
(d) Each external door must be located where persons using them will not be endangered by the propellers when appropriate operating procedures are used.
(e) There must be a provision for direct visual inspection of the locking mechanism to determine if external doors, for which the initial opening movement is not inward (including passenger, crew, service, and cargo doors), are fully closed and locked. The provision must be discernible under operational lighting conditions by appropriate crewmembers using a flashlight or equivalent lighting source. In addition, there must be a visual warning means to signal the appropriate flight crewmembers if any external door is not fully closed and 1150
locked. The means must be designed such that any failure or combination of failures that would result in an erroneous closed and locked indication is improbable for doors for which the initial opening movement is not inward.
(f) External doors must have provisions to prevent the initiation of pressurization of the airplane to an unsafe level if the door is not fully closed and locked. In addition, it must be shown by safety analysis that inadvertent opening is extremely improbable.
(g) Cargo and service doors not suitable for use as emergency exits need only meet paragraphs (e) and (f) of this section and be safeguarded against opening in flight as a result of mechanical failure or failure of a single structural element.
(h) Each passenger entry door in the side of the fuselage must meet the applicable requirements of §§ 25.807 through 25.813 for a Type II or larger passenger emergency exit.
(i) If an integral stair is installed in a passenger entry door that is qualified as a passenger emergency exit, the stair must be designed so that under the following conditions the effectiveness of passenger emergency egress will not be impaired:
(1) The door, integral stair, and operating mechanism have been subjected to the inertia forces specified in § 25.561 (b)(3), acting separately relative to the surrounding structure.
(2) The airplane is in the normal ground attitude and in each of the attitudes corresponding to collapse of one or more legs of the landing gear.
(j) All lavatory doors must be designed to preclude anyone from becoming trapped inside the lavatory, and if a locking mechanism is installed, it be capable of being unlocked from the outside without the aid of special tools.
[Amdt. 25-15, 32 FR 13262, Sep. 20, 1967; Amdt. 25-23, 35 FR 5676, Apr. 8, 1970; Amdt. 25-54, 45 FR 60173, Sep. 11, 1980; Amdt. 25-72, 55 FR 29780, Jul. 20, 1990; Amdt. 25-88, 61 FR 57956, Nov. 8, 1996]
b. Intent of Rule. The intent of this rule is to ensure that external doors will not open in flight, either inadvertently by persons as a result of mechanical failure, or failure of a single structural element.
Failures in the door that would cause the door to open in flight must be extremely improbable.
c. Background. This rule was carried forward from § 4b.356 of the Civil Air Regulations (CAR).
The rule was amended to include consideration of failure of a single structural element (Amendment 25
23). Amendment 25-54 made a significant change to the rule by requiring a means of preventing pressurization unless the door was fully closed and locked. It also specified a minimum reliability for the door warning system.
d. Acceptable Compliance Methods. For guidance on compliance with this requirement, refer to the preamble of Amendment 25-15, 32 FR 13262, September 20, 1967; Amendment 25-23, 35 FR 5676, April 8, 1970; Amendment 25-54, 45 FR 60173, September 11, 1980; Amendment 25-72, 1151
55 FR 29780, July 20, 1990; and Amendment 25-88, 61 FR 57956, November 8, 1996. Advisory Circular (AC) 25.783-1, or latest revision, provides guidance information for showing compliance with structural and functional safety standards for doors and their operating systems. For the purpose of showing compliance with § 25.783, hatches and exits are also considered to be doors.
e. References. Advisory Circular 25.783-1, or latest revision, Fuselage Doors, Hatches, and Exits.
1039 - 1049. [RESERVED] 1050. SECTION 25.785 - SEATS, BERTHS, SAFETY BELTS, AND HARNESSES.
a. Rule Text.
(a) A seat (or berth for a nonambulant person) must be provided for each occupant who has reached his or her second birthday.
(b) Each seat, berth, safety belt, harness, and adjacent part of the airplane at each station designated as occupiable during takeoff and landing must be designed so that a person making proper use of these facilities will not suffer serious injury in an emergency landing as a result of the inertia forces specified in §§ 25.561 and 25.562.
(c) Each seat or berth must be approved.
(d) Each occupant of a seat that makes more than an 18-degree angle with the vertical plane containing the airplane centerline must be protected from head injury by a safety belt and an energy absorbing rest that will support the arms, shoulders, head, and spine, or by a safety belt and shoulder harness that will prevent the head from contacting any injurious object. Each occupant of any other seat must be protected from head injury by a safety belt and, as appropriate to the type, location, and angle of facing of each seat, by one or more of the following:
(1) A shoulder harness that will prevent the head from contacting any injurious object.
(2) The elimination of any injurious object within striking radius of the head.
(3) An energy absorbing rest that will support the arms, shoulders, head, and spine.
(e) Each berth must be designed so that the forward part has a padded end board, canvas diaphragm, or equivalent means, that can withstand the static load reaction of the occupant when subjected to the forward inertia force specified in § 25.561. Berths must be free from corners and protuberances likely to cause injury to a person occupying the berth during emergency conditions.
(f) Each seat or berth, and its supporting structure, and each safety belt or harness and its anchorage must be designed for an occupant weight of 170 1152
pounds, considering the maximum load factors, inertia forces, and reactions among the occupant, seat, safety belt, and harness for each relevant flight and ground load condition (including the emergency landing conditions prescribed in § 25.561). In addition -
(1) The structural analysis and testing of the seats, berths, and their supporting structures may be determined by assuming that the critical load in the forward, sideward, downward, upward, and rearward directions (as determined from the prescribed flight, ground, and emergency landing conditions) acts separately or using selected combinations of loads if the required strength in each specified direction is substantiated. The forward load factor need not be applied to safety belts for berths.
(2) Each pilot seat must be designed for the reactions resulting from the application of the pilot forces prescribed in § 25.395.
(3) The inertia forces specified in § 25.561 must be multiplied by a factor of 1.33 (instead of the fitting factor prescribed in § 25.625) in determining the strength of the attachment of each seat to the structure and each belt or harness to the seat or structure.
(g) Each seat at a flight deck station must have a restraint system consisting of a combined safety belt and shoulder harness with a single-point release that permits the flight deck occupant, when seated with the restraint system fastened, to perform all of the occupant's necessary flight deck functions. There must be a means to secure each combined restraint system when not in use to prevent interference with the operation of the airplane and with rapid egress in an emergency.
(h) Each seat located in the passenger compartment and designated for use during takeoff and landing by a flight attendant required by the operating rules of this chapter must be:
(1) Near a required floor level emergency exit, except that another location is acceptable if the emergency egress of passengers would be enhanced with that location. A flight attendant seat must be located adjacent to each Type A or B emergency exit. Other flight attendant seats must be evenly distributed among the required floor level emergency exits to the extent feasible.
(2) To the extent possible, without compromising proximity to a required floor level emergency exit, located to provide a direct view of the cabin area for which the flight attendant is responsible.
(3) Positioned so that the seat will not interfere with the use of a passageway or exit when the seat is not in use.
(4) Located to minimize the probability that occupants would suffer injury by being struck by items dislodged from service areas, stowage compartments, or service equipment.
(5) Either forward or rearward facing with an energy absorbing rest that is designed to support the arms, shoulders, head, and spine.
1153