Schweizer 269 separation of the cabin door while in flight SAIB SW-09-44

Note: EASA SIB SW-09-44 - Safety Information Bulletin: WITHDRAWN – REPLACED BY EASA AD 2010-0219

This Special Airworthiness Information Bulletin (SAIB) informs you, owners or operators, of an airworthiness concern regarding possibility of separation of the cabin door while in flight for the following Schweizer Models: 269A, TH-55A, 269A-1, 269B, 269C, serial numbers 001 through 1917, 269C-1, serial numbers 0001 through 347, and 269D, serial numbers 0001 through 0073.

Background
There are two door hinges for each cabin door on Schweizer models 269 series aircraft. Each door hinge consists of the hinge pin assembly which is attached to the airframe and the door hinge plate which contains top and bottom hinge pin receptacles installed on the door. The hinge pin assembly has two door hinge pins with a spring located in between. The two hinge pin receptacles are openedend cylinders. When the door is installed on aircraft, the spring-loaded door hinge pins engage the top and bottom hinge pin receptacles respectively. Serrated hinge pins (Schweizer Pilot’s Flight Manual refers these pins as hinge pin tabs) are installed on each door hinge pin to provide travel stops to the door hinge pins inside the hinge pin receptacles, and they are also used to retract the door hinge pins out of the hinge pin receptacles for door removal. The serrated hinge pins are secured in position by an interference press fit. Loss of the serrated hinge pin will result in lost of retention of the door hinge pin inside the hinge pin receptacle. When both serrated hinge pins inadvertently come off from the door hinge pins, the stop is lost and the spring will push the lower door hinge pin through the hinge pin assembly and falls out of the open end of the bottom hinge pin receptacle. With the lower door hinge pin missing at the bottom hinge pin receptacle, the upper door hinge pin inside the top hinge pin receptacle will drop down, and the vibrations of the aircraft will cause the upper door hinge pin to fall out of the bottom hinge pin receptacle. The door hinge plate will separate from the hinge pin assembly which could result in separation of the door from the aircraft.

The full SAIB is attached