Narrative:
The aircraft, a Learjet 35A, N22MS, experienced a runway overrun upon landing at McMinnville Municipal Airport, Oregon.
The aircraft sustained substantial damage and the three passengers onboard were not injured.
The airplane had just undergone a flight management system (FMS) upgrade at a maintenance facility in Grand Junction, and this was both its first flight, and its home base return flight, following the upgrade.
The pilot reported that the flight and landing approach were uneventful. As the airplane touched down on runway 22, the pilot deployed the spoilers, and then pulled the power levers to the thrust reverser detent position; however, the deploy indicators did not illuminate. He then recycled the thrust levers back into the detent, but again the reversers did not deploy. Both the pilot and copilot attempted to troubleshoot as the airplane continued along the runway. The pilot then applied pressure to the foot pedal brakes, but did not feel a response; the copilot also attempted, but reported that the pedals felt loose and the airplane did not slow down. As the airplane approached the threshold, the pilot engaged the steering lock switch, and attempted to steer the nose wheel, but the airplane did not respond. Just prior to reaching the runway end, he activated the emergency braking lever; however, the airplane rolled off the runway end, through a set of instrument landing system antennas, and down an embankment.
Subsequent examination revealed that the mounting screws for both the left and right main landing gear squat switches were loose, such that the switches had backed away from their mounting pads.
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
Failure of maintenance personnel to reattach the landing gear squat switches following maintenance, which rendered the airplane's steering, braking, and thrust reverser systems inoperative during landing. Contributing to the accident were the failure of both the maintenance facility mechanics and the airplane operator's mechanic and flight crew to identify the error during post maintenance checks, a failure of the airplane's pilot to apply the emergency brakes in a timely manner, and the copilot's decision to attempt to engage the thrust reversers as the airplane approached the runway end despite multiple indications that they were inoperative and producing partial forward, rather than reverse, thrust.
Runway excursion (overrun)
accident date: 13-05-2013
type: Learjet 35A
registration: N22MS
accident date: 13-05-2013
type: Learjet 35A
registration: N22MS
| Status: | Accident investigation report completed and information captured |
| Date: | Monday 13 May 2013 |
| Time: | 12:45 |
| Type: |  Learjet 35A |
| Operator: | Evergreen International Aviation |
| Registration: | N22MS |
| MSN: | 35A-209 |
| First flight: | 1978 |
| Total airframe hrs: | 15047 |
| Cycles: | 9491 |
| Engines: | 2 Garrett TFE731-2-2B |
| Crew: | Fatalities: 0 / Occupants: 2 |
| Passengers: | Fatalities: 0 / Occupants: 1 |
| Total: | Fatalities: 0 / Occupants: 3 |
| Aircraft damage: | Substantial |
| Aircraft fate: | Written off (damaged beyond repair) |
| Location: | McMinnville Municipal Airport, OR ( United States of America)
|
| Phase: | Landing (LDG) |
| Nature: | Ferry/positioning |
| Departure airport: | Grand Junction-Walker Field, CO (GJT/KGJT), United States of America |
| McMinnville Municipal Airport, OR (KMMV), United States of America |
The aircraft, a Learjet 35A, N22MS, experienced a runway overrun upon landing at McMinnville Municipal Airport, Oregon.
The aircraft sustained substantial damage and the three passengers onboard were not injured.
The airplane had just undergone a flight management system (FMS) upgrade at a maintenance facility in Grand Junction, and this was both its first flight, and its home base return flight, following the upgrade.
The pilot reported that the flight and landing approach were uneventful. As the airplane touched down on runway 22, the pilot deployed the spoilers, and then pulled the power levers to the thrust reverser detent position; however, the deploy indicators did not illuminate. He then recycled the thrust levers back into the detent, but again the reversers did not deploy. Both the pilot and copilot attempted to troubleshoot as the airplane continued along the runway. The pilot then applied pressure to the foot pedal brakes, but did not feel a response; the copilot also attempted, but reported that the pedals felt loose and the airplane did not slow down. As the airplane approached the threshold, the pilot engaged the steering lock switch, and attempted to steer the nose wheel, but the airplane did not respond. Just prior to reaching the runway end, he activated the emergency braking lever; however, the airplane rolled off the runway end, through a set of instrument landing system antennas, and down an embankment.
Subsequent examination revealed that the mounting screws for both the left and right main landing gear squat switches were loose, such that the switches had backed away from their mounting pads.
Probable Cause:
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
Failure of maintenance personnel to reattach the landing gear squat switches following maintenance, which rendered the airplane's steering, braking, and thrust reverser systems inoperative during landing. Contributing to the accident were the failure of both the maintenance facility mechanics and the airplane operator's mechanic and flight crew to identify the error during post maintenance checks, a failure of the airplane's pilot to apply the emergency brakes in a timely manner, and the copilot's decision to attempt to engage the thrust reversers as the airplane approached the runway end despite multiple indications that they were inoperative and producing partial forward, rather than reverse, thrust.
Accident investigation:
 |
|
Classification:
Wrong installation of parts Runway excursion (overrun)
Sources:
» NTSBPhotos
accident date: 13-05-2013
type: Learjet 35A
registration: N22MS
accident date: 13-05-2013
type: Learjet 35A
registration: N22MS
Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Grand Junction-Walker Field, CO to McMinnville Municipal Airport, OR as the crow flies is 1368 km (855 miles).
Distance from Grand Junction-Walker Field, CO to McMinnville Municipal Airport, OR as the crow flies is 1368 km (855 miles).
This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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