Aircraft near Arlington, VA — 2011-03-23

Probable cause

The tower controller's loss of consciousness induced by lack of sleep, fatigue resulting from working successive midnight shifts, and air traffic control scheduling practices.

NTSB narrative

Between approximately 0004 and 0028 local time, an air traffic control service interruption occurred at the Ronald Reagan Washington National Airport when two air carrier aircraft, a helicopter, an airport operations vehicle, and controllers at the Federal Aviation Administration's Potomac Terminal Radar Approach Control were unable to establish contact with the supervisory controller working alone in the control tower. Two air carrier aircraft landed during the period without tower contact. Postincident investigation revealed that the controller on duty had the necessary preconditions for the development of fatigue at the time of the event, specifically acute sleep loss in the 24 hours before the event and circadian disruption as a result of working the midnight shift.

Analysis

Primary failure mode

Human factors

First missed decision gate

PCT controller should have directed AAL1012 to hold instead of land.

NTSB coding

• Air traffic event · Other
• Impairment / Incapacitation

Evidence available

• ATC audio
• ADS-B / radar
• 14 docket documents

Docket documents14

• ATC 3 - AAL1012 Radar Dataatc
• ATC 3 - DCA Airport Diagramatc
• ATC 3 - DCA Transcriptatc
• ATC 3 - FAA National Guidance Night Operationsatc
• ATC 3 - Flight tracks of AAL1012 and UAL628T near DCAatc
• ATC 3 - Mount Vernon Charted Visual Approachatc
• ATC 3 - Potomac TRACON Transcriptsatc
• ATC 3 - UAL628T Radar Dataatc
• Operations 2 - AAL1012 Captain Statementinterview
• Operations 2 - AAL1012 First Officer Statementinterview
• Operations 2 - UAL628T Crew Statementsinterview
• Operations 2 - United Flight Operations Manual Excerptsother
• Operations 2 - United Ops Specification C080other
• Operations 2 - Flight Operations Reportreport