Viewing page 49 of 51

This transcription has been completed. Contact us with corrections.

Colonial Airlines, Inc. 
Maintenance Department Page 1 of 3

S.L. #6357
12/27/48

Eng. Release #422

TO: All Maintenance & Station Personnel
FROM: Director of Maintenance & Overhaul
SUBJECT: "Air-Stair" Door Installation DC-3 NC-21758

The "Air-Stair" passenger cabin door installed on NC-21758 is a specially designed door which features a passenger stair that is an integral part of the door. The stair. located on the interior side of the door. is utilized by lowering the bottom hinged door downward. In this position the door is supported by two guard chains which are permanently attached to the fuselage structure on each side of the door. In the open and down position the door clears the ground by approximately six inches. When the door is closed. it is positively secured by three bayonet loading pins. The front pin actuates the door warning micro switch and the warning light will remain "On" until the locking mechanism completely extends the pin to the fully locked position.  (Refer to sketch, page 2, for additional details of door design.

Advantages that accrue from the use of the "Air-Stair" Door are reduction in operating costs through elimination of ground ramp equipment, and time economy at stops on short scheduled runs.

Certain design differences in the "Air-Stair" door, as compared to the conventional passenger cabin door, require special consideration in use of the door. Precautions listed in the following paragraphs must be observed to prevent unecessary maintenece due to careless handling of the door.

During normal operation of the door, when opened and closed from the outside, these precautions must be observed.
        1. open the door by turning external handle to "Open" position. graps the door firmly and lower carefully tothe full "down " position.
        2. close the door by lifting to the full "up" position and then turning the outside door.handle to the "locked" position.
CAUTION: Door handle must be turned to the positive lock position to assure that it is securely latched and will not drop down when released. (Handle returns to neutral or streamlined position when released! ) After passenger loading.and the door has been closed from the outside, the inside door handle should be visually checked by stewardess for closed position. (Handle in line with painted indices for closed position. Ref: Drawing page 2.)

In the event that it is necessary for flight or mechanic personnel to open the door from inside the UD 61 lock mechanism should be rotated to the open position, and the door then lowered slowly and carefully with the guard chains. As the weight of the door passes over center considerable pull will be exerted on the guard chains.  CAUTION: Door must be lowered slowly for full distance of travel. Do not drop door as this would place a heavy shock load on the hinges and ship's structure!