L-1011 General Aircraft Characteristics: Exhaust at Ground Idle (25-7)

The high bypass ratio provides for lower exhaust temperatures than attained with current [as of 1974] jets with a lower bypass ratio.

With the center engine at idle, exhaust velocity is at 50 miles per hour at 200 feet behind the tail. From the wing engines, this velocity occurs 140 feet behind the tail.

Lockheed suggested that you you apply breakaway power with the wing engines only, and that you exercise special caution at Gates, especially those with large windows.