# NTSB CHI85FA070: Piper PA-31, N9011Y, Pontiac, MI, December 12, 1984

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: December 11, 1984, 19:32 local (Dec 12, 1984, 00:32 UTC)
- Place: Pontiac, MI
- Location: 42.6566° N, 83.4783° W: Placed by OpenAirDocs from NTSB’s distance and direction from OAKLAND COUNTY INTL (PTK), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=42.6566&lon=-83.4783&mi=10
- Phase of flight: [Unknown](https://openairdocs.org/ntsb-phases/990) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 12815
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI85FA070
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/12815/pdf
- Page: https://openairdocs.org/ntsb/CHI85FA070

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Airframe/component/system failure/malfunction, unknown
  - pneumatic system - no pressure (contributing factor)
  - operation with known deficiencies in equipment - improper, pilot in command (cause)
  - improper use of equipment/aircraft, pilot in command (cause)
  - flight/nav instruments,attitude gyro - disabled (contributing factor)
  - judgment - improper, pilot in command (cause)
  - psychological condition, pilot in command (contributing factor)
  - flight/nav instruments,attitude indicator - false indication (contributing factor)
  - maintenance,installation - improper, company maintenance personnel (cause)
  - pressure, pilot in command (contributing factor)
- Loss of control - in flight, approach - faf/outer marker to threshold (ifr)
  - flight/nav instruments,attitude indicator - false indication
  - emergency procedure - not followed, pilot in command (cause)
  - improper use of procedure, pilot in command (cause)
  - qualification, pilot in command (contributing factor)
  - lack of experience, pilot in command (contributing factor)
  - lack of recent experience, pilot in command (contributing factor)
  - lack of recent experience in type operation, pilot in command (contributing factor)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

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 & OUTFLOW FITTINGS OF THE LEFT PUMP. NO CONTAMINANTS WERE FOUND IN THE RT PUMP BUT THE PUMP WALL INNER SURFACES GAP WAS APPRX .005 IN. THIS GAP IS APPROX 50 PERCENT OVER THE ALLOWABLE TOLERANCE FOR A SERVICEABLE AIR PUMP.THE PRESSURE REGULATOR VALVE TO THE ATTITUDE INDICATOR GYRO & THE COMPASS GYRO WERE EXAMINED & FOUND TO REQUIRE PRESSURE EXCEEDING NORMAL REQUIREMENT STANDARDS.

## Aircraft

- Registration: N9011Y (not matched to a registry record)
- Reported make and model: PIPER PA-31
- Category: Airplane
- Serial number: 3116
- Airframe hours: 3979
- Engines: LYCOMING TI0-540-A1A 310 horsepower reciprocating
- Damage: Destroyed
- Flight: Part 135
- Registered owner: Richards Aviation, Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, December 3, 1984, 5 hours before
- Departed: M08, BOLIVAR, TN
- Destination: PTK, PONTIAC, MI
- Flight plan: IFR
- Airport: PTK, Oakland Pontiac

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 31; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; toxicology performed; flight hours: 2,247 total, 2,117 as pilot in command, 182 in the last 90 days, 104 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Instrument (IMC), Night/dark
- Wind: 180° at 12 knots
- Visibility: 75 statute miles
- Lowest ceiling: 100 ft
- Altimeter: 29.00 inHg
- Observed at: PTK, 3 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19841211065669A](https://openairdocs.org/incident/19841211065669A), Dec 11, 1984: Piper PA31, Pontiac, MI, Destroyed. Hit pole and trees on approach. Started flight with one dry air pump out, other reading low. Maintenance a factor.

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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