During the LM jettison, in a brief conversation with YAW Will Pressley, Jack Garman warns him that "transience in separation" might cause a CSM gimbal lock to occur. He's referring specifically to oscillations in attitude as a result of the delta-V imparted on the CSM in separation. The deadband isn't as much of a concern since the spacecraft is in a 5-degree deadband; thus, the middle gimbal angle is moving between 10 and 20 degrees from gimbal lock.
Later, one of the AGC support personnel calls the gimbal lock warning, but because his voice on the loop is so faint, it's missed and it's a full 3 or 4 seconds before anyone from the ground brings this to the attention of FLIGHT/CAPCOM. By that point, it's already too late and Swigert has already gone to direct control to correct this, but Garman does take this as an opportunity to remind Pressley of his concerns.
Link:
Before gimbal lock -
https://apolloinrealtime.org/13/?t=141:15:37&ch=22Gimbal lock -
https://apolloinrealtime.org/13/?t=141:30:14&ch=22
Topic: 141:15:37 Jack Garman predicts LM jettison gimbal lock (Read 442 times)