More forces from that direction tore off the vertical fin , which came Motion away with portions of the fuselage , already weakened Cause_change_of_strength from losing Earnings_and_losses the left stabilizer , still attached Connect .

There was no rupture Destroying of any hydraulic system , so the pilots still had control Control of the ailerons , the right elevator , and the horizontal stabilizer .

The accident was caused Causation by atmospheric icing Change on the horizontal stabilizer .

An investigation by the USAF determined Deciding that the crash was likely caused Causation by an improper stabilizer trim setting .

The investigation was unable to determine Deciding conclusively what had caused the horizontal stabilizer trim to be set Placing improperly , but theorized Coming_to_believe that the most likely cause was an aircraft system malfunction Motion .