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Last updated: 27 February 2021
Statuts:Enquête Officielle
Date:lundi 13 mai 2013
Heure:12:45
Type/Sous-type:Silhouette image of generic LJ35 model; specific model in this crash may look slightly different
Learjet 35A
Compagnie:Evergreen International Aviation
Immatriculation: N22MS
Numéro de série: 35A-209
Année de Fabrication: 1978
Heures de vol:15047
Cycles:9491
Moteurs: 2 Garrett TFE731-2-2B
Equipage:victimes: 0 / à bord: 2
Passagers:victimes: 0 / à bord: 1
Total:victimes: 0 / à bord: 3
Dégats de l'appareil: Substantiels
Conséquences: Written off (damaged beyond repair)
Lieu de l'accident:McMinnville Municipal Airport, OR (   Etats-Unis d'Amérique)
Phase de vol: A l'atterrissage (LDG)
Nature:Convoyage
Aéroport de départ:Grand Junction-Walker Field, CO (GJT/KGJT), Etats-Unis d'Amérique
Aéroport de destination:McMinnville Municipal Airport, OR (KMMV), Etats-Unis d'Amérique
Détails:
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:
cover
Investigating agency: NTSB
Status: Investigation completed
Duration: 1 year and 6 months
Accident number: WPR13FA227
Download report: Summary report

Sources:
» NTSB


Photos

photo of Learjet-35A-N22MS
accident date: 13-05-2013
type: Learjet 35A
registration: N22MS
photo of Learjet-35A-N22MS
accident date: 13-05-2013
type: Learjet 35A
registration: N22MS
 

Plan
Ce plan montre l'aéroport de départ ainsi que la supposée destination du vol. La ligne fixe reliant les deux aéroports n'est pas le plan de vol exact.
La distance entre Grand Junction-Walker Field, CO et McMinnville Municipal Airport, OR est de 1368 km (855 miles).

Les informations ci-dessus ne représentent pas l'opinion de la 'Flight Safety Foundation' ou de 'Aviation Safety Network' sur les causes de l'accident. Ces informations prélimimaires sont basées sur les faits tel qu'ils sont connus à ce jour.
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