Date & Time:
Sep 4, 1987 at 2245 LT
Type of aircraft:
Cessna 208A Caravan
Operator:
Registration:
N807LA
Flight Phase:
Flight
Flight Type:
Cargo
Survivors:
Yes
Site:
Plain, Valley
Schedule:
San Antonio – Dallas
MSN:
208-0026
YOM:
1985
Country:
United States of America
Region:
North America
Crew on board:
1
Crew fatalities:
0
Pax on board:
0
Pax fatalities:
0
Other fatalities:
0
Total fatalities:
0
Captain / Total hours on type:
750
Aircraft flight hours:
222
Circumstances:
After leveling at 5,500 feet, the standby power annunciator light illuminated, followed by loss of oil pressure. The pilot turned back toward the airport, but there was a progressive loss of engine power and the prop went to a feathered position. During an emergency landing at night, the aircraft hit a power line and trees, then crashed. During an engine teardown, disassembly of the reduction gearbox scavenge pump revealed that a retaining nut and tang washer (w/i the scavenge pump) had backed off and lodged between the spur gears, which resulted in a sheared scavenge pump drive shaft. In turn, this resulted in the loss of oil pressure and allowed the prop to feather.
Probable cause:
Occurrence #1: airframe/component/system failure/malfunction
Phase of operation: cruise - normal
Findings
1. (c) lubricating system, oil scavenge pump - loose
2. (c) lubricating system, oil scavenge pump - jammed
3. (c) lubricating system, oil scavenge pump - failure, total
4. Initiated
----------
Occurrence #2: loss of engine power (total) - mech failure/malf
Phase of operation: cruise
Findings
5. (c) fluid, oil - starvation
----------
Occurrence #3: forced landing
Phase of operation: descent - emergency
----------
Occurrence #4: in flight collision with object
Phase of operation: landing
Findings
6. (f) light condition - night
7. (f) object - wire, transmission
8. (f) object - tree(s)
----------
Occurrence #5: in flight collision with terrain/water
Phase of operation: descent - uncontrolled
Phase of operation: cruise - normal
Findings
1. (c) lubricating system, oil scavenge pump - loose
2. (c) lubricating system, oil scavenge pump - jammed
3. (c) lubricating system, oil scavenge pump - failure, total
4. Initiated
----------
Occurrence #2: loss of engine power (total) - mech failure/malf
Phase of operation: cruise
Findings
5. (c) fluid, oil - starvation
----------
Occurrence #3: forced landing
Phase of operation: descent - emergency
----------
Occurrence #4: in flight collision with object
Phase of operation: landing
Findings
6. (f) light condition - night
7. (f) object - wire, transmission
8. (f) object - tree(s)
----------
Occurrence #5: in flight collision with terrain/water
Phase of operation: descent - uncontrolled
Final Report:
N807LA.pdf89.54 KB
