Date & Time:
Feb 6, 1985 at 0943 LT
Type of aircraft:
Cessna 402
Operator:
Registration:
N5780M
Flight Phase:
Takeoff (climb)
Flight Type:
Scheduled Revenue Flight
Survivors:
No
Schedule:
Altus - Oklahoma City
MSN:
402B-0358
YOM:
1973
Country:
United States of America
Region:
North America
Crew on board:
1
Crew fatalities:
1
Pax on board:
1
Pax fatalities:
1
Other fatalities:
0
Total fatalities:
2
Captain / Total hours on type:
643
Aircraft flight hours:
6100
Circumstances:
During an engine start, prior to the flight, the left engine backfired 2 or 3 times. A witness described the 1st backfired as 'the loudest I have ever heard.' When the aircraft took off, two persons living near the departure end of the runway noted that the aircraft (believed to be the same) sounded different and had a 'cluttering sound'. While climbing, the pilot declared an emergency and reported a fire in the left engine. He was vectored toward Altus AFB while descending in IFR conditions. He descended into VFR conditions and saw the airport about 3 miles away. A witness saw smoke and fire trailing from the vicinity of the left engine. He stated that the aircraft's nose came up, the plane rolled to the left, then it entered a steep, nose down, inverted attitude just before it crashed and burned. An exam revealed the engine exhaust manifold header assy had failed and allowed hot exhaust gases to escape in the engine nacelle in the vicinity of fuel and oil lines. Corrosion had progressed thru the header assy. Ad 75-23-08 requested general inspection, but contained note 'do not remove clamps.' No record of replacement in 6,100 hours. Both occupants were killed.
Probable cause:
Occurrence #1: airframe/component/system failure/malfunction
Phase of operation: unknown
Findings
1. (c) exhaust system, manifold/pipe - corroded
2. (c) maintenance, inspection - inadequate
3. (f) procedure inadequate - manufacturer
4. (f) inadequate surveillance of operation - faa (organization)
5. (c) exhaust system, manifold/pipe - failure,total
6. (c) exhaust system, manifold/pipe - leak
----------
Occurrence #2: fire
Phase of operation: climb - to cruise
Findings
7. (c) miscellaneous - fire
----------
Occurrence #3: loss of control - in flight
Phase of operation: approach - vfr pattern - final approach
Findings
8. (c) reason for occurrence undetermined
9. (f) weather condition - clouds
10. Initiated - pilot in command
11. Precautionary landing - attempted - pilot in command
12. Aircraft handling - not maintained
----------
Occurrence #4: in flight collision with terrain/water
Phase of operation: descent - uncontrolled
Phase of operation: unknown
Findings
1. (c) exhaust system, manifold/pipe - corroded
2. (c) maintenance, inspection - inadequate
3. (f) procedure inadequate - manufacturer
4. (f) inadequate surveillance of operation - faa (organization)
5. (c) exhaust system, manifold/pipe - failure,total
6. (c) exhaust system, manifold/pipe - leak
----------
Occurrence #2: fire
Phase of operation: climb - to cruise
Findings
7. (c) miscellaneous - fire
----------
Occurrence #3: loss of control - in flight
Phase of operation: approach - vfr pattern - final approach
Findings
8. (c) reason for occurrence undetermined
9. (f) weather condition - clouds
10. Initiated - pilot in command
11. Precautionary landing - attempted - pilot in command
12. Aircraft handling - not maintained
----------
Occurrence #4: in flight collision with terrain/water
Phase of operation: descent - uncontrolled
Final Report:
N5780M.pdf90.06 KB
