Accident Piper PA-22-108 N4712Z,
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ASN Wikibase Occurrence # 43823
 
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Date:Monday 16 April 2007
Time:16:00
Type:Silhouette image of generic PA22 model; specific model in this crash may look slightly different    
Piper PA-22-108
Owner/operator:Private
Registration: N4712Z
MSN: 22-8256
Year of manufacture:1961
Total airframe hrs:2525 hours
Fatalities:Fatalities: 1 / Occupants: 2
Aircraft damage: Substantial
Category:Accident
Location:Ava, MO -   United States of America
Phase: En route
Nature:Private
Departure airport:Lakeview, AR (3M0)
Destination airport:Mountain Grove, MO (1MO)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
The passenger reported that during cruise flight the airplane inexplicably began a shallow left turn that the pilot was unable to counteract. The pilot reportedly moved the yoke to the left and right without any effect on the left bank angle. The airplane continued the unintended left turn with an increasingly steeper bank angle for three complete turns. The passenger reported that the airplane's pitch was vertically nose-down at the completion of the third turn, at which time the airplane impacted trees and terrain. The aileron control cable circuit was examined during the investigation. The inboard end of the right aileron upper cable was missing its eye splice and thimble. The cable had an approximate 90 degree bend at the location corresponding to the eye, consistent with residual deformation associated with an eye loop. The cable separation did not exhibit any kinking or heavy rubbing. The remaining sleeve (nicropress) on the right aileron upper cable did not conform to the manufacturer's specified crimp dimensions and had tooling markings that were not consistent with the use of the specified installation tool. In a properly installed eye splice, the cable should fracture before pulling out of its corresponding sleeve. The aileron cables used had a specified limit load of 2,000 pounds. The remaining eye splice on the right aileron upper cable pulled out of its sleeve at 476 pounds. The other five eye splices tested held more than 1,600 pounds before failure occurred in the cable. A review of the aircraft's maintenance logbooks did not reveal any specific mention of aileron control cable replacement. However, given the variability in the appearance and characteristics of the other aileron cable sleeves, it is likely that the nonconforming sleeves were not of original manufacture.

Probable Cause: The failure of the aileron cable eye splice during cruise flight. Contributing to the accident were improper installation and service of the crimped cable sleeve, which rendered the airplane uncontrollable.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: CHI07LA104
Status: Investigation completed
Duration:
Download report: Final report

Sources:

NTSB: https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20070508X00523&key=1

Location

Revision history:

Date/timeContributorUpdates
28-Oct-2008 00:45 ASN archive Added
21-Dec-2016 19:24 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
04-Dec-2017 18:37 ASN Update Bot Updated [Operator, Other fatalities, Source, Narrative]

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