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ASN Wikibase Occurrence # 1074
Last updated: 24 August 2020
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Date:15-FEB-2005
Time:13:30 UTC
Type:Silhouette image of generic DH82 model; specific model in this crash may look slightly different
de Havilland DH.82A Tiger Moth
Owner/operator:Private
Registration: G-ALIW
C/n / msn: 82901
Fatalities:Fatalities: 0 / Occupants: 2
Other fatalities:0
Aircraft damage: Substantial
Category:Accident
Location:Private Strip at Littlebredy, Dorchester, Dorset -   United Kingdom
Phase: Landing
Nature:Training
Departure airport:Littlebredy, Dorchester, Dorset
Destination airport:Littlebredy, Dorchester, Dorset
Investigating agency: AAIB
Narrative:
The purpose of the flight was for an instructor to revalidate the pilot's Private Pilot's Licence. The intention was to practice circuits followed by upper air work and a short cross-country with a practice forced-landing. After the instructor had demonstrated a 'three-point' landing, the pilot performed a 'wheeler' landing, intending to allow the tail to settle before applying power to go around. However, before the tailskid touched, the right undercarriage collapsed and the aircraft tipped onto its nose and right wingtip before settling back in an upright attitude.

The instructor reported that the touchdown was normal and states that the damage was relatively light due to the low ground speed at the time of the collapse. Both pilots evacuated the aircraft normally.

The instructor, who is a retired metallurgist, found that the right undercarriage drag strut had detached from the fitting securing it to the fuselage due to failure of the swivel bolt, part number H.22186.On a brief visual examination, he diagnosed that the fracture involved a fatigue crack. One half of the fracture was sent to the AAIB for examination: this concurred with his diagnosis with the additional observation that it appeared to be low-cycle fatigue occurring over a relatively short period and that the bolt passing through the strut fork fitting and the swivel bolt appeared to have been excessively tightened at some point.

The history of the failed item is unknown but a report was found, dated 1960, in which a De Havilland investigation identified an almost identical failure. The report did not recommend any action as "this is the first recorded defect of this particular nature".

The maintainer of the aircraft has advised that he intends to inspect the swivel bolts during annual inspection of Tiger Moth aircraft in future and it would seem prudent for other maintainers to do likewise. The age and history of these components is scarcely ever recorded and loads experienced can vary great with runway conditions and also the effectiveness of lubrication, since the bolt must be free to articulate in the fitting as the undercarriage struts 'spread' under load.

Damage to propeller, underside of lower wing and detached undercarriage strut on right side.

Sources:

1. AAIB: https://assets.publishing.service.gov.uk/media/5422f5daed915d13710005b3/G-ALIW_07-05.pdf
2. CAA: https://siteapps.caa.co.uk/g-info/rk=ALIW
3. http://dorset.hampshireairfields.co.uk/dorcrash.html
4. http://www.airhistory.org.uk/dh/p829.html
5. http://www.laa-archive.org.uk/results.php?q=G-ALIW&fields=reg

Accident investigation:
cover
  
Investigating agency: AAIB
Status: Investigation completed
Duration:
Download report: Final report


Images:

Photo of G-ALIW courtesy AirHistory.net


Old Warden (EGTH)
31 July 2016; (c) Alex Christie

Related books:

Revision history:

Date/timeContributorUpdates
27-Jan-2008 23:23 JINX Added
21-Aug-2008 13:33 JINX Updated
03-Dec-2014 22:05 Dr. John Smith Updated [Operator, Departure airport, Destination airport, Source, Embed code, Narrative]
03-Dec-2014 22:08 Dr. John Smith Updated [Narrative]
09-Aug-2016 20:24 Dr.John Smith Updated [Source]

Corrections or additions? ... Edit this accident description