Great Lakes Aviation Flight 7125
Beech 1900D · Accident: landing gear collapse
From Denver International Airport (DEN) to Telluride Regional Airport (TEX)
Event
- NTSB case
- DCA13FA148
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Airline
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Beech 1900D
- Aircraft type
- Beechcraft 1900
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N169GL
- Operator
- Great Lakes Aviation
- Onboard fatalities
- Unknown
- Route
- From Denver International Airport (DEN), Denver, COTo Telluride Regional Airport (TEX), Telluride, CO
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 121: Air Carrier
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Landing · landing roll
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Landing gear collapse
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Aircraft › Aircraft systems
- Not determined › Not determined
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
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.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DCA13FA148
- Event ID
- 20130901X95021
- Case number
- DCA13FA148
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 0e0289d95cf51eed15fa471eda132e0a02eb4cfdb5059dd1d2cd3e5bf9e96447; retrieved 2026-09-15T22:41:42.225Z.