Crash of a Piper PA-31-310 Navajo in Pontiac: 2 killed
Date & Time:
Dec 11, 1984 at 1932 LT
Registration:
N9011Y
Survivors:
No
Schedule:
Bolivar - Pontiac
MSN:
31-16
YOM:
1967
Crew on board:
2
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
2
Aircraft flight hours:
3979
Circumstances:
The aircraft departed the airport with one dry air pump inoperative and the other pump reading low. Aircraft control was lost during an instrument approach in IMC approximately 2.5 hours later. Both pump driveshafts were found sheared in the wreckage and both broken shaft surfaces showed polished surfaces. During further testing it was discovered that tape or pipe dope had been used in the threading of the intake and outflow fittings of the left pump. No contaminants were found in the right pump but the pump wall inner surfaces gap was approximately .005 inch. This gap is approx 50% over the allowable tolerance for a serviceable air pump. The pressure regulator valve to the attitude indicator gyro and the compass gyro were examined and found to require pressure exceeding normal requirement standards. Both occupants were killed.
Probable cause:
Occurrence #1: airframe/component/system failure/malfunction
Phase of operation: unknown
Findings
1. (f) pneumatic system - no pressure
2. (c) operation with known deficiencies in equipment - improper - pilot in command
3. (c) improper use of equipment/aircraft - pilot in command
4. (f) flight/nav instruments, attitude gyro - disabled
5. (c) judgment - improper - pilot in command
6. (f) psychological condition - pilot in command
7. (f) flight/nav instruments, attitude indicator - false indication
8. (c) maintenance, installation - improper - company maintenance personnel
9. (f) pressure - pilot in command
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Occurrence #2: loss of control - in flight
Phase of operation: approach - faf/outer marker to threshold (ifr)
Findings
10. Flight/nav instruments,attitude indicator - false indication
11. (c) emergency procedure - not followed - pilot in command
12. (c) improper use of procedure - pilot in command
13. (f) qualification - pilot in command
14. (f) lack of experience - pilot in command
15. (f) lack of recent experience - pilot in command
16. (f) lack of recent experience in type operation - pilot in command
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Occurrence #3: in flight collision with terrain/water
Phase of operation: descent - uncontrolled
Phase of operation: unknown
Findings
1. (f) pneumatic system - no pressure
2. (c) operation with known deficiencies in equipment - improper - pilot in command
3. (c) improper use of equipment/aircraft - pilot in command
4. (f) flight/nav instruments, attitude gyro - disabled
5. (c) judgment - improper - pilot in command
6. (f) psychological condition - pilot in command
7. (f) flight/nav instruments, attitude indicator - false indication
8. (c) maintenance, installation - improper - company maintenance personnel
9. (f) pressure - pilot in command
----------
Occurrence #2: loss of control - in flight
Phase of operation: approach - faf/outer marker to threshold (ifr)
Findings
10. Flight/nav instruments,attitude indicator - false indication
11. (c) emergency procedure - not followed - pilot in command
12. (c) improper use of procedure - pilot in command
13. (f) qualification - pilot in command
14. (f) lack of experience - pilot in command
15. (f) lack of recent experience - pilot in command
16. (f) lack of recent experience in type operation - pilot in command
----------
Occurrence #3: in flight collision with terrain/water
Phase of operation: descent - uncontrolled
Final Report:
