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ASN Wikibase Occurrence # 220504
Last updated: 19 October 2020
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Date:03-JAN-2019
Time:16:00
Type:Silhouette image of generic PA24 model; specific model in this crash may look slightly different
Piper PA-24-250 Comanche
Owner/operator:Private
Registration: N6872P
C/n / msn: 24-2007
Fatalities:Fatalities: 0 / Occupants: 2
Other fatalities:0
Aircraft damage: Substantial
Category:Accident
Location:Near Wilkes-Barre Wyoming Valley Airport (KWBW), Wilkes-Barre, PA -   United States of America
Phase: Landing
Nature:Training
Departure airport:Towanda, PA (N27)
Destination airport:Wilkes-Barre, PA (WBW)
Investigating agency: NTSB
Narrative:
The pilot, who was an airframe and powerplant mechanic, and the flight instructor both reported that, after turning onto the base leg at the end of the instructional flight, the pilot extended the landing gear in preparation to land; however, the gear did not fully extend, and the engine stopped producing power. The pilots made a forced landing to a soccer field short of the runway, during which the airplane struck a ditch and sustained substantial damage to the airframe. A postaccident examination of the airplane and engine revealed no obvious preimpact mechanical anomalies with the landing gear system or the engine. However, the pilot later stated that he had opened the engine cowling after the forced landing and saw the mixture cable was caught in the nose gear assembly. The pilot said he then unsnagged the cable, so it was not immediately obvious to investigators. He said that the mixture cable had gotten caught on the nosewheel assembly when it was trying to extend, which had caused the mixture control arm on the carburetor to move to the lean position.

The pilot had performed maintenance on the landing gear a few weeks before the accident. He used plastic tie-wraps to ensure the throttle/mixture/carburetor heat cables were positioned away from the nose gear, which does not have a protected well on this make/model airplane. He then flew the airplane and placed it back in his hangar until the accident flight. The pilot said there were a lot of mice in his hangar, and he thought a mouse got up in the engine and chewed off the plastic tie-wraps, which allowed the mixture cable to come loose. However, there was no evidence to support this theory.

A review of the airplane's Illustrated Parts Catalogue showed the mixture, throttle, and carburetor heat cables routed and secured away from the nose landing gear via metal clamps. Additional research of the Federal Aviation Administration Service Difficulty Reports (SDRs) revealed only one reported instance in which the mixture control cable got caught in the nose landing gear on this make/model airplane. The December 2003 report stated that, due to the mixture control cable not being properly secured or routed, it encountered the nose gear assembly during extension and fuel to the engine was shut off. The mechanic who submitted the SDR corrected the situation by properly routing and securing the mixture control cable.

Given the available evidence, the mixture control cable in the accident airplane was not properly installed/secured. As a result, the cable caught on the nose landing gear assembly when the landing gear were extended and subsequently pulled the mixture control arm on the carburetor, thus shutting off fuel to the engine.

Probable Cause: The pilot/mechanic's improper installation and securing of the mixture control cable, which led to a simultaneous loss of total engine power and failure of the nose landing gear to fully extend when the cable caught on the nose landing gear assembly.

Sources:

NTSB: https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20190104X82250&key=1
FAA register: https://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=6872P%20

Accident investigation:
cover
  
Investigating agency: NTSB
Status: Investigation completed
Duration: 1 year and 7 months
Download report: Final report

Media:


Revision history:

Date/timeContributorUpdates
03-Jan-2019 22:40 Geno Added
03-Jan-2019 23:04 Geno Updated [Registration, Cn, Operator, Source]
03-Jan-2019 23:05 Geno Updated [Date]
04-Jan-2019 00:27 RobertMB Updated [Registration, Location, Source]
04-Jan-2019 02:12 Iceman 29 Updated [Source, Embed code]
15-Aug-2020 16:00 ASN Update Bot Updated [Time, Operator, Nature, Departure airport, Destination airport, Source, Damage, Narrative, Accident report, ]

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