The Grounding of Certain Glued Aircraft - 1960s

In the early 1960s, DCA concerns over the continuing airworthiness of the synthetic resin glues used in the construction of certain wartime and early post-war aircraft led to the wholesale grounding and near extinction of several types.

The grounding order was prompted by the investigation of an accident involving a Percival Proctor V, VH-AIE, which broke up in flight near Wiluna, WA on 25 August 1962. The aircraft had only flown 655 hours in its 16 years. Then a Miles Messenger in Queensland, VH-AVD, had its aileron control cables jammed on 14 November due to the timber structure carrying the aileron control arm breaking away at its glued joints, however the aircraft landed safely. Both aircraft had complied with all maintenance and inspection requirements to keep their Certificate of Airworthiness (CofA) continually renewed and both had been always hangared, but in hot climates.

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The type-grounding instructions came in several stages in the early '60s. First were the Ansons, which were initially subject to frequent and intensive inspections from 1959 due to deterioration of the glued joints in the wooden wing and tailplane. Because of the structural problems, combined with unsatisfactory single-engined performance, they were then banned from carrying passengers or operating over-water routes from 1 January 1962, and grounded as of 1 July 1962.

< Click on the image at left to download a series of documents from the CAHS collection regarding the Anson grounding. (2.2 MB .pdf file)

DCA Anson VH-CAD - click here to find out more < This decision also affected DCA's fleet of Ansons.

On 21 September 1962 the Minister announced that the CofAs for six types, totalling 28 individual aircraft, would not be valid after 31 December 1963 and, furthermore, that they were immediately banned from carrying passengers. This action was due to their wooden structures utilising synthetic resin glues which were proven to have deteriorating strength due age and high temperatures. The affected types were:

  • Percival Proctor Mk.V (the postwar civil production model)
  • DH.94 Moth Minor (including Australian-built aircraft by De Havilland Australia)
  • Miles Gemini
  • Miles Messenger
  • Miles Mercury
  • Mraz Sokol M1C

DCA concern over certain glues also caused them to order a modification to early production Yeoman YA-1 Cropmasters, an agricultural derivative of the Commonwealth Aircraft Corporation CA-6 Wackett which had received type-certification with the Wackett's original wooden tailplane. In 1962 Yeoman were ordered to replace the tailplane with an all-metal design, which superseded the original wooden unit at great expense to Yeoman and the ag operators.

Click here for more about the preservation of Proctor VH-AUC An Airworthiness Directive also ordered inspections of the glued joints in wings of Percival Proctors Mk.Is and Mk.IIIs, which were wartime military production models using different glues. A section of the wing spar had to be exposed and a "pull-test" broke laminated wood away to test the glue adhesion.

Not unlike the witch trials of the middle ages, if the aircraft passed the tests the owner faced a large bill to replace the damage caused by the test. This effectively grounded almost all the Australian Proctors during the mid 1960s.

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Click to download Anson grounding docs