Boeing 737 N27239 and Gulfstream Aerospace G1159B N909JE incident near Worton, Maryland

Probable cause

The R10/12 controller issued an improper vector and descent clearance to the GII that put the airplane on a coverging flight path with the B737. Contributing to the incident was the failure of the FAA's training program to correct ongoing controller performance deficiencies before certifying the D10/12 controller to work without immediate supervision.

NTSB analysis

On March 25, 2010, at 0904 eastern daylight time, an operational error occurred at the Washington Air Route Traffic Control Center (ZDC) when Continental Airlines flight 239 (COA239), a Boeing 737-800, en route from Miami, Florida, to Newark, New Jersey, and N909JE, a Gulfstream II en route from Palm Beach, Florida, to Teterboro, New Jersey, passed within 1.04 miles laterally and 300 feet vertically over Worton, Maryland. Both aircraft were operating on instrument flight plans in class A airspace under control of ZDC. Required minimum separation between the aircraft was 5 miles and 1000 feet. There was no damage reported to either aircraft and no injuries to passengers or crew.

When interviewed, the R12 controller stated that she turned the GII east to avoid entering restricted airspace over Aberdeen, Maryland. The heading issued to avoid the restricted area put the GII on a converging heading with the B737, with both aircraft descending to FL240. Minimum separation occurred as both aircraft descended through FL279 and FL276, respectively, with 1.04nm lateral separation.

Review of the R12 controller's training records showed numerous recurring writeups for not maintaining positive control of situations, not taking timely action when required, and use of poor control judgment. Similar issues contributed to the loss of separation between the B737 and GII.

Text from the NTSB. Open the NTSB docket for OPS10IA014 for the full record.