LJ35, Aberdeen SD USA, 1999

Summary: 

On 25 October 1999, a Learjet 35, being operated on a passenger charter flight by Sunjet Aviation, crashed in South Dakota following loss of control attributed to crew incapacitation.

Event Details
When: 
25/10/1999
Event Type: 
Day/Night: 
Day
Flight Conditions: 
VMC

18632

Flight Details
Operator: 
Type of Flight: 
Public Transport (Passenger)
Flight Origin: 
Take-off Commenced: 
Yes
Flight Airborne: 
Yes
Flight Completed: 
No
Phase of Flight: 
Climb
Location
Approx.: 
near Aberdeen, South Dakota
General
Tag(s): 
Inadequate Airworthiness Procedures, Inadequate Aircraft Operator Procedures, Ineffective Regulatory Oversight, Root Cause Not Determined
HF
Tag(s): 
Inappropriate crew response (technical fault), Flight Crew Incapacitation
AW
System(s): 
Air Conditioning and Pressurisation
Contributor(s): 
Inadequate QRH Drills, Pilot verbal-only defect communication
Outcome
Damage or injury: 
Yes
Aircraft damage: 
Hull loss
Non-aircraft damage: 
No
Non-occupant Casualties: 
No
Occupant Injuries: 
None
Occupant Fatalities: 
Most or all occupants
Off Airport Landing: 
No
Ditching: 
No
Causal Factor Group(s)
Group(s): 
Aircraft Operation, Aircraft Technical
Safety Recommendation(s)
Group(s): 
None Made
Investigation Type
Type: 
Independent

Description

On 25 October 1999, a Learjet 35, being operated on a passenger charter flight by Sunjet Aviation from Orlando to Dallas Fort Worth, crashed in South Dakota following loss of control attributed to crew incapacitation following insufficient oxygen intake after an apparent failure of the pressurisation during the climb.

Synopsis

This is the summary from the official report into the accident published by the National Transportation Safety Board (NTSB) (USA).

"On October 25, 1999, about 1213 central daylight time (CDT), a Learjet Model 35, N47BA, operated by Sunjet Aviation, Inc., of Sanford, Florida, crashed near Aberdeen, South Dakota. The airplane departed Orlando, Florida, for Dallas, Texas, about 0920 eastern daylight time (EDT). Radio contact with the flight was lost north of Gainesville, Florida, after air traffic control (ATC) cleared the airplane to flight level (FL) 390. The airplane was intercepted by several U.S. Air Force (USAF) and Air National Guard (ANG) aircraft as it proceeded northwestbound. The military pilots in a position to observe the accident airplane at close range stated (in interviews or via radio transmissions) that the forward windshields of the Learjet seemed to be frosted or covered with condensation. The military pilots could not see into the cabin. They did not observe any structural anomaly or other unusual condition. The military pilots observed the airplane depart controlled flight and spiral to the ground, impacting an open field. All occupants on board the airplane (the captain, first officer, and four passengers) were killed, and the airplane was destroyed."

The probable cause of the accident was given as:

"The National Transportation Safety Board determines the probable cause of this accident was incapacitation of the flight crewmembers as a result of their failure to receive supplemental oxygen following a loss of cabin pressurization, for undetermined reasons."

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