1.   Investigators discovered a malfunction in the propeller pitch control and a worn part in a propeller control system on the left engine.

2.   Losing the left engine is trickier since it drives both the single generator and the sole hydraulic pump.

3.   The pilot reported engine problems, and survivors said they could see the left engine begin to come apart.

4.   And last December, the crew shut down the left engine after hearing a loud pop, and the plane landed safely.

5.   Are those sparks flying from the left engine?

6.   But the recorder did capture a sharp drop in thrust from the right engine and a smaller drop from the left engine.

7.   But they may not know until Columbia returns to Earth why the cockpit gauge erroneously indicated at the same time that the left engine was underpowered.

8.   For the first time, Gannaway peered over his left shoulder and saw the damage to the left engine.

9.   French television showed clips of the aircraft struggling to maintain altitude with its left engines spewing flames.

10.   In order to make a turn, he then boosted power to the left engine.