A Canberra PR9 was flying in the Farnborough area today.
On the subject of Canberra FI, there was a brilliant BBC programme many years ago, Open University probably, about this very subject.
Not sure where it was filmed but they related the tale of aircraft that had been withdrawn from service due to cracking in the centre section forgings and sent for repair, the cracks actually grew in length while waiting their turn in the line for new crossover beams.
Pogno….I remember them showing us that film when I was an apprentice with RAE Bedford.
The problem (if I remember right) was that the forgings had been heat treated (normalised) before the lightening cutouts had been made and so it effectively uncovered the areas of high stresses deep inside the forging where the aluminium takes longer to cool down. This resulted in the catastrophic cracks you mention.
I believe the cure was a post machining heat treatment to normalise all the high stress areas…
Didn’t they have to have a massive refurbishment program to replace all the suspect Centre Section Forgings way back in the early days of the Canberra? Way before my time but someone here may be able to confirm?
25deg south….
Stress corrosion cracking is still an issue for us on the undercarrige legs and we have to NDT the whole U/C every 6 months now!! and yes you are correct…even if the parts have sat on the stores shelf!! 🙁
Regards all
Chris
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