TM 1-410. Technical Manual, Airplane Structures 1941: Section 12 - Cockpits and Cabins

SECTION XII: COCKPITS AND CABINS

45. General.-a. The pilot's cockpit is that portion of the airplane occupied by the pilot or by the pilot and assistant pilot from which all controls radiate and in which furnishings, instruments, and equipment are installed in positions accessible or usable to the pilot or to the pilot and assistant pilot, as the case may be. Single-place airplanes have one cockpit (accommodation for pilot only) and two-place or tandem-seat airplanes have two. In the latter case certain controls, instruments, and equipment are either duplicated or placed in positions visible and accessible from both cockpits. Bombardment, cargo, and other large and special type airplanes have a pilot and copilot compartment in addition to the bomb compartments, cabins, etc. In most cases the cockpits are designed to be completely inclosed to protect the pilot and crew from atmospheric conditions.

b. All airplanes are equipped with a baggage and tool compartment appropriate to the crew and intended mission of the airplane. These compartments are readily accessible from cockpits, cabins, or from the outside of the airplane and are provided with locks mounted flush with the covering or embodied in the handles.

46. Inclosures, windshields, and windows.-To provide necessary vision and facilitate inspection, transparent materials are used in these units, and where practicable in covering parts requiring frequent inspection. The two types of materials used are laminated glass and noninflammable transparent sheet usually mounted in a metal frame which is kept as inconspicuous as possible, particularly where it intercepts vision. Canopies as shown in figure 57 completely inclose the cockpit opening. They generally consist of several sections which are mounted to slide, using rollers and a track, thereby providing an entrance to and exit from the cockpit. For use in an emergency a panel of the canopy and in some instances the entire canopy is designed for quick release. Emergency releases are always prominently marked and are within easy reach of the pilot and crew, as shown in figure 58. Gunner canopies are often dome-shaped and mounted on a turntable or turret.

47. Doors.-All doors provided for entrance to and exit from the cockpits and cabins of airplanes hinge along the forward or the bottom edge of the closed door and are provided with latches. The latch handle on the outside of the door is comparatively small and is streamlined, while the latch handle on the inside of the door is generally large and conspicuous, often surmounted by a knob. On transport, airplanes. the cabin door is arranged so that it can he disengaged completely from its attachment by a single movement of a release lever to facilitate rapid evacuation of passengers in an emergency.

48. Ventilators.--a. Ventilation of airplanes, whether separate from or in conjunction with the heating system, is usually provided by ventilating ports opening to the outside and equipped with controllable deflectors at the inner ends. Such ports are so located that they promote a circulation of fresh air throughout the entire cockpit or cabin which may be regulated and directed at discretion of the occupants.

b. Temperatures injurious to radio equipment, instruments, etc., will develop in closed cockpits of airplanes parked in the sun in hot weather. In order to prevent such excessive temperatures all airplanes so parked, other than those on which locking all means of ingress to the airplane is mandatory, should have the cockpit inclosures, doors, hatches, and windows kept open to allow circulation of air.

49. Seats.-a. Pilot seats used in military airplanes, as shown in figure 59, are made of sheet aluminum or aluminum alloy pressed to shape. Edges are rolled and sides cut low to provide freedom of arm movement of the occupant. The bottom of the seat is deeply dished to accommodate the seat-pack parachute carrier which serves as a seat cushion. The back of the seat is usually high and provided with clips for supporting a life preserver pad which serves as a back

FIGURE 57.-Cockpit inclosure.

cushion. On most airplanes this seat is adjustable as to height. This is accomplished by mounting the seat between tubular uprights, one on either side of the cockpit, and using locking pins or pawls carried on journals attached to the seat to engage the uprights at selected points. The seat height is regulated by first operating the release lever mounted on the seat. base to disengage the locking pins. The seat may then be pulled upward by the shock cord or forced downward by the occupant's weight. Usually a choice of six to eight positions is provided.

FIGURE 58-Emergency exit release, cockpit inclosure.

6. Observer seats are identical with the pilot seat. Gunner seats, however, are usually mere pedestal stools, pivoted and mounted so as to afford the gunner full range of movement. Cabin seats are similar to the pilot seat, but as a rule are nonadjustable for height. Provisions are made in the means of attachment for quick removal of cabin seats for conversion of the cabin into an ambulance or cargo compartment.

c. All seats and chairs are equipped with safety belts as shown in figure 59. Normally a safety belt should be fastened properly about each occupant at all times during take-offs, flights, and landings. Before taking off the pilot should see that the safety belt is properly secured to the airplane and fastened about each occupant, and that each person taking part in the flight understands fully the method of releasing the belt. Where possible, each safety belt should be installed or fastened so that the movable hook or latch of the fastening device is on the left of the two connecting belt ends. In some installations, pilot belts of standard length cannot be shortened sufficiently by strap adjustment only to fit properly all individuals. In

(1) Front view.
FIGURE 59.-Pilot seat.

such cases the belt may be shortened further by overlapping and stitching the webbing in an approved manner.

50. Maintenance.-a. Seats should be inspected regularly for cracks and sharp projections which might catch or tear the parachute or clothing of the occupant. If a damaged seat cannot be repaired satisfactorily, it should be removed and replaced. The adjustment mechanism should be lubricated periodically and the shock cord renewed when it becomes deteriorated or weakened.

b. Windshields, canopies, and windows are all subject to scratches and clouding. Clouding of glass sections may be minimized by sealing the laminated edges with paint. These sections may be cleaned and polished with metal polish, care being taken not to rub hard particles of sand or grit into the surface. First rinse the surface

(2) Rear view.
FIGURE 59.-Pilot seat--Continued.

with water, then wipe lightly with a soft cloth. Kerosene or naphtha may be used to remove grease or oil. The padding provided about each individual section of glass or composition should be maintained to minimize cracking resulting from vibration and the frame must be kept attached firmly in place. A cracked unit should be replaced as soon as possible. Foreign matter must be kept out of the turret tracks and all sliding sections must be so maintained as to operate f reely.

c. All safety belts are tested in the stretched-out position, as shown in figure 60, with a weight of 500 pounds, with the exception of some types of gunner safety belts which are, tested with a weight of 250 pounds. When testing the weight must be raised gently from the floor to avoid impact loading, and lowered immediately to avoid placing unnecessary stresses on the belt. No attempt should be made to tear the stitching or webbing of safety belts by hand. Each belt found to be defective or deteriorated in any part or shows any evidence of weakening or failure during the test will be condemned. As each belt is tested, the date on which the work is accomplished is stenciled on the webbing of each section, using figures approximately 1/2 inch high. The first date recorded should be so arranged and located that the subsequent test can be recorded in chronological order. The date recorded will show the month, day, and year, for example, 1-1-38, 7-1-38, 1-1-39, etc.

FIGURE 60.-Safety belt tester.