CHI85FA070 · Piper PA-31
Piper PA-31 · Accident: airframe, component or system failure
From William L. Whitehurst Field (M08) to Oakland County International Airport (PTK)
Event
- NTSB case
- CHI85FA070
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 2 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Charter & commuter
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Instrument Meteorological Cond
Piper PA-31
- Aircraft type
- Piper PA-31
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N9011Y
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From William L. Whitehurst Field (M08), Bolivar, TNTo Oakland County International Airport (PTK), Pontiac, MI
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 135: Air Taxi & Commuter
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Unknown
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Airframe, component or system failure
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Company maintenance personnel › Maintenance, installation, improper
- Pilot in command › Emergency procedure, not followed
- Pilot in command › Improper use of equipment/aircraft
- Pilot in command › Improper use of procedure
- Pilot in command › Judgment, improper
- Pilot in command › Operation with known deficiencies in equipment, improper
Approximate · Estimated position: the centre of Pontiac, MI, the place the record names. Not the accident site.
NTSB narrative
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.
Verbatim NTSB analysis from the NTSB dataset
Sources
NTSB record CHI85FA070
- Event ID
- 20001214X41731
- Case number
- CHI85FA070
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1984-12-12.
- API snapshot SHA-256: e8bd54eefee61429999df5db51ba1564dedb227ba02e046aaf25b5d61ca198e4; retrieved 2026-09-18T14:27:22.133Z.