Aviation Accident Summaries

Aviation Accident Summary CEN17LA091

Delta, CO, USA

Aircraft #1

N303QB

BEECH 95-C55

Analysis

The airplane experienced a gear-up landing after the private pilot was unable to extend the landing gear. Postaccident examination of the landing gear motor revealed that the sector gear teeth were partially sheared and were bound with the worm gear teeth, resulting in interference. Once the gear was turned past the sheared area, the assembly functioned with no anomalies. Review of maintenance logs revealed that the most recent annual inspection, which included the landing gear system, was completed about 6 months before the accident with no anomalies noted.

Factual Information

On January 18, 2017, at 1630 mountain standard time, a Beech 95-C55, N303QB, experienced a gear-up landing at Blake Field Airport, Delta, Colorado, after the pilot was unable to extend the landing gear using normal and emergency procedures. The airplane sustained substantial damage on impact with the runway surface. The pilot was uninjured. The airplane was registered to and operated by the pilot under 14 Code of Federal Regulations Part 91 as a personal flight that was not operating on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The flight originated from an unknown location. A National Transportation Safety Board (NTSB) Pilot Operator Aircraft Accident/Incident Report, Form 6120.1 was not received from the pilot, who was required to complete and submit the form following email and phone requests by the NTSB Investigator-In-Charge. The pilot was also requested to provide his pilot logbook but that request was not complied with. A post-accident disassembly examination, by a maintenance facility, of the airplane landing gearbox showed that there were three labels attached to the gearbox exterior: a "Beech Aircraft Corporation", part number "95-810017-23 ECH," serial number "94-B-479," a Beechcraft Rebuilt Part," part number "95-810017-23 ECH," serial number "94-B-479," and a "Cruiseair Aviation, Inc." with no part or serial number annotated. The examination revealed that the sector gear was against the stop "so hard" that the bolt for the stop could not be removed until the assembly half screws were removed. The sector gear teeth were partially sheared and were bound with worm gear teeth resulting in interference. Once the gear was turned past the sheared area, the assembly worked "fine." An airplane logbook entry dated November 22, 2014 stated that at a tachometer time of 5,211.40 hours and unknown total time, the landing gear failed to electrically extend and the emergency gear handle was hard to turn for the first two turns. The landing gearbox was sent to "Cruiseair" for "repair/inspection." Gearbox, part number "95-810017-25," serial number "94-13-479," was overhauled and reinstalled. The entry states that there were no defects found when the landing gear was cycled three times, and an emergency landing gear extension was performed. An airplane logbook entry dated July 19, 2016 stated that an airplane total time of 5,239.7 hours, the "landing gear, motor, and actuating linkage" were inspected during an annual inspection. The airplane was placed on jacks and the landing gear was cycled and an emergency landing gear extension was performed with "satisfactory results."

Probable Cause and Findings

The failure of the landing gear to extend during landing approach due to the interference between the landing gear motor's sector and worm gears.

 

Source: NTSB Aviation Accident Database

Get all the details on your iPhone or iPad with:

Aviation Accidents App

In-Depth Access to Aviation Accident Reports