Date:	Sunday 1 September 2013
Time:	13:09
Type:	Beechcraft 1900D
Owner/operator:	Great Lakes Airlines
Registration:	N169GL
MSN:	UE-169
Year of manufacture:	1995
Total airframe hrs:	35184 hours
Engine model:	Pratt & Whitney Canada PT6A-67D
Fatalities:	Fatalities: 0 / Occupants: 12
Aircraft damage:	Substantial, repaired
Category:	Accident
Location:	Telluride Airport, CO (TEX) -   United States of America
Phase:	Landing
Nature:	Passenger - Scheduled
Departure airport:	Denver International Airport, CO (DEN/KDEN)
Destination airport:	Telluride Airport, CO (TEX/KTEX)
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
A Beechcraft 1900D passenger plane operating as flight GLA7125 from Denver International Airport, CO (DEN) to Telluride Airport, CO (TEX) was damaged in a landing accident on runway 27.
During approach to landing the crew selected landing gear down and observed a problem with the left main landing gear (MLG). The landing gear hydraulic motor pump automatically shut down when the landing gear was not locked down after 16 seconds and an internal mechanical lock intended to hold the landing gear actuator in the selected position, did not engage.
The crew carried out the abnormal procedures checklist and attempted to extend the left MLG using the manual landing gear extension procedures, but was unsuccessful. The crew then prepared for landing in accordance with the procedures contained in the quick reference handbook for landing with main gear up or unsafe.
As the airplane slowed through about 80 knots on the landing roll, the left main landing gear collapsed.
Post-accident inspection indicated hydraulic fluid had leaked from a hole, which was normally plugged with a Lee plug, on the left main actuator between the primary and secondary extend ports. The Lee plug was missing and was not found. Examination of the actuator and of the hydraulic fluid quantity remaining indicated the Lee plug was in place during the in-flight attempts to extend the landing gear.
The airplane landed with the gear not locked down and as the landing gear collapsed, the piston in the actuator forced hydraulic fluid back through the system increasing the landing gear actuator internal hydraulic pressure sufficiently to force the Lee plug out of position. The remaining fluid in the actuator leaked out of the hole until system pressure decreased to ambient pressure.

PROBABLE CAUSE: "Failure of the left main landing gear actuator internal lock to engage in the locked position for undetermined reasons."

18:55 UTC / 12:55 local time:
KTEX 011855Z AUTO 26009G16KT 10SM BKN065 BKN090 OVC110 20/08 A3043 RMK AO2 LTG DSNT N NE AND S

19:15 UTC / 13:15 local time:
KTEX 011915Z AUTO 09003KT 10SM TS SCT065 OVC100 21/07 A3043 RMK AO2 LTG DSNT N

NTSB

photo (c) Leslie Snelleman; Denver International Airport, CO (DEN/KDEN); 03 March 2012

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