History of Flight
On September 1, 2013, at about 1310 mountain daylight time, Great Lakes Airlines flight 7125, a Beechcraft 1900D (N169GL), experienced a left main landing gear collapse during landing on runway 27 at Telluride Regional Airport, Telluride, Colorado. The two flight crew members and ten passengers were not injured. The aircraft sustained substantial damage. The scheduled passenger flight operated under 14 CFR Part 121 and originated from Denver International Airport.
The first officer was the pilot flying, and the captain was the pilot monitoring. Takeoff, climb, and cruise were normal.
At 1231, the crew selected landing gear down and observed a problem with the left main landing gear. The captain began the "Failure of Landing Gear to Extend Normally" checklist. Both green left landing gear down and locked lights were not illuminated, and the landing gear circuit breaker had tripped.
At 1240, the captain began the "Landing Gear Manual Extension" checklist and contacted maintenance control via radio. The crew noted no green left gear down and locked indication, a red in-transit light illuminated, and the circuit breaker tripped. After discussing fuel burn, safety concerns, and ARFF capabilities, the crew decided to land at Telluride.
At 1247, the captain attempted to pump the landing gear down per the checklist but reported the extension handle would not move.
At 1250, the captain began the "Gear Up Landing" and "Planned Emergency Preparation" checklists. He requested ARFF services and briefed passengers.
At 1259, the captain began the "Landing with One Main Up or Unsafe" checklist. During the landing roll, as the airplane slowed through about 80 knots, the left main landing gear collapsed. The airplane stopped on runway 27 at 1309, and the crew initiated an evacuation.
Injuries to Persons
There were no injuries to the 10 passengers or 2 crew members on board.
Damage to Aircraft
The airplane sustained substantial damage, coming to rest on the nose landing gear, the right main landing gear, and the left wingtip. The left wingtip lower skin suffered abrasion damage. The left inboard flap was deformed and wrinkled, and the trailing edge and aft nacelle were abraded. The left outboard flap was deformed and wrinkled, and the trailing edge was abraded. The left aileron had abrasion damage. The left ventral strake was damaged along its lower edge. The left engine inboard machined mount fitting was fractured, and the firewall was deformed and bent. The left engine and propeller were also damaged.
Personnel Information
The flight crew consisted of two pilots, and the accident occurred on their first flight of the day. The captain, age 32, reported 5,800 hours total flight time, including 4,700 hours as pilot in command and 3,000 hours in the BE-1900. He held a valid FAA ATP certificate with type ratings for EMB-120 and BE-1900 and a first-class medical certificate with a corrective lenses limitation.
The first officer, age 30, reported 2,576 hours total flight time, including 1,350 hours pilot-in-command and 1,350 hours in the BE-1900. He held a valid ATP certificate with a BE-1900 type rating and a first-class medical certificate with no limitations.
Aircraft Information
N169GL, serial number UE-169, was a Beech 1900D equipped with two Pratt and Whitney PT6A-65B turboprop engines. The airplane had logged 35,184 hours total time on the airframe at the time of the accident. Recorded data and airline records indicated no open maintenance items.
The landing gear system is a retractable tricycle type, with hydraulic actuators for extension and retraction. Hydraulic pressure is supplied by a power pack in the left wing leading edge. The system operates at 3,000 psi with a relief valve.
Landing gear position is indicated by six green lights and two red in-transit lights. A relay circuit breaker protects against electrical overload and trips if the gear does not lock after about 16 seconds of pump operation.
Manual extension involves a handle on the pilot's side floor. The landing gear control lever must be in the down position, the relay circuit breaker pulled, and the handle pumped until green lights illuminate.
Maintenance records showed the left main landing gear actuator was overhauled in September 2011 and installed in March 2012. Since installation, landing gear problems were noted in June 2012, September 2012, and July 2013, including three instances where the gear would not retract. These were corrected by maintenance on safety switches.
Meteorological Information
Day visual meteorological conditions prevailed. The Telluride surface observation at 1255 MDT reported wind from 260 degrees at 9 knots gusting to 16 knots, visibility 10 statute miles, 6,500 feet broken, 11,000 feet overcast, temperature 20°C, dew point 8°C, and altimeter 30.43 inches of mercury.
Aerodrome Information
Telluride Regional Airport is about 5 miles west of Telluride, CO. Runway 27 is asphalt, 7,111 feet long and 100 feet wide, with a touchdown zone elevation of 9,070 feet. It is served by a PAPI with a 4-degree glide path on the left side.
Flight Recorders
The cockpit voice recorder (CVR) was removed and downloaded. It contained 2 hours, 4 minutes of recording with excellent audio quality except for the cockpit area microphone (fair). The flight data recorder (FDR) contained about 98 hours of data, though the pitch parameter was out of calibration.
Tests and Research
Initial inspection revealed several circuit breakers popped out, including LANDING GEAR RELAY, LANDING GEAR WARNING HORN, TAWS, CKPT VOICE RCDR, and 26VAC FLT DATA RCDR. The landing gear selector lever was in the DOWN position, and the alternate extension handle was not stowed.
Hydraulic fluid was found on the left main actuator and strut. The hydraulic system was pressurized, and fluid exited a hole on the left main actuator between the primary and secondary extend ports. The hole was a design feature intended to be plugged with a Lee plug. The Lee plug was missing and not found. The end cap was removed; no damage was found. Functional testing after fitting a new end cap revealed no anomalies.
Disassembly showed normal wear on internal components, but dimensional analysis indicated some measurements exceeded drawing tolerances: lock spring length, slide length, piston length, outside diameter of the piston, and inside diameter of the end cap and cup. Hydraulic fluid analysis showed NAS Class 12 due to high particle count in the 5-15 micron range; Beech had no set cleanliness limit for the 1900 series.
Organizational Information
Great Lakes Airlines operated as a 14 CFR Part 121 carrier with a fleet of 6 Embraer EMB-120 and 28 Beechcraft 1900D aircraft. The accident airplane was owned by Great Lakes Aviation Ltd. and operated by Great Lakes Airlines.