Later theories conclude that the pilots thought their difficulty controlling the plane was due to clear - air turbulence .
The transmission was sent before pilots were aware of the wing 's deficiency , if indeed pilots ever knew before the wing failed .
Later theories conclude that the pilots thought their difficulty controlling the plane was due to clear - air turbulence , and the transmission was sent before they were aware of the wing 's deficiency , if indeed they ever knew before the wing failed .