Beech B58 Baron, VH-EZB, Tindal, Northern Territory, on 18 February 1990

Circumstances:

Following a period a local familiarisation flying, the landing was selected down, pre-landing checks were completed and a green down-and-locked indication obtained. The aircraft subsequently landed on the lower fuselage, main landing gear doors, flaps, and propeller tips. During the investigation, a retraction test and partial disassembly of the landing gear mechanism confirmed that the extension cycle had terminated prematurely. This termination was caused by interference with the down limit and indicator microswitches mounting plate by the up-limit actuating screw. Movement and activation of these switches terminated the gear down travel and presented a false gear down-and-locked indication. Only the main landing gear doors extended before the cycle stopped.

Significant Factors:

The following factors were considered relevant to the development of the accident:

1. Failure of the landing gear to extend after a "down" selection - due to mechanical interference of the down limit switch.

2. Failure of the landing gear indicator to indicate an unsafe gear situation - due to mechanical interference of the down indicator switch. This accident was not the subject of an on-scene investigation.