Only 26 pilots lost their lives due to this defect, before it was rectified. It was put down to compressibility. In a steep dive, the tiffie would compress and so the pilot would throttle right back and use trimming to bring it out of the dive. As soon as the plane's speed dropped, and the controls started to respond normally, the attitude of the trimming gear pulled the nose up sharply and applied a breaking strain to the rear fuselage.
This was partly cured by riveting 20 fish plates around the fuselage, but I have no info on when this was done or the exact specifications, funked.
- Dowding