What happened
TWA Flight 388, operating a DC-9 with registration N924L, was flying under instrument flight rules (IFR) and climbing toward an altitude of 7,000 feet within the Baltimore (BWI) Air Route Traffic Control Center (TRACON) area. The aircraft was currently inside cloud cover when Baltimore TRACON controllers identified a potential conflict with another aircraft, a Piper PA-28R, located directly ahead at a distance of three miles and descending from 6,700 feet.
At the time the alert was issued, Flight 388 had already passed 6,000 feet. The captain of Flight 388 requested a traffic avoidance vector to resolve the situation. In response, the TRACON controller instructed the flight to level off at 6,000 feet and turn left to a heading of 270 degrees. However, due to the aircraft's momentum and rate of climb, Flight 388 had already reached 6,400 feet by the time the instruction was processed.
As Flight 388 executed the left turn, it broke through the top of the cloud layer. The aircrew immediately sighted the Piper PA-28R at their one o'clock position. Both crews took evasive action to avoid a collision. The TWA captain reported that the Piper passed approximately 500 to 1,000 feet laterally with no vertical separation. Conversely, the Piper pilot stated he saw Flight 388 emerging from the clouds in a left turn and estimated the separation to be approximately three-quarters of a mile.
Both aircraft were in communication with Baltimore TRACON but were operating on different radio frequencies and were being handled by different controllers. Notably, Flight 388 was being managed by a trainee controller at the time of the incident.