IAD05LA138 · Piper PA-46-500TP
Piper PA-46-500TP · Accident: loss of control in flight en route
From Steven A. Bean Municipal Airport (8B0) to Lehigh Valley International Airport (ABE)
Event
- NTSB case
- IAD05LA138
- 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
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- 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
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Piper PA-46-500TP
- Aircraft type
- Piper PA-46
- 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
- N747AW
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Steven A. Bean Municipal Airport (8B0), Rangeley, METo Lehigh Valley International Airport (ABE), Allentown, PA
- 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 91: General Aviation
- 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
- En route · climb to cruise
- 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
- Loss of control in flight
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Flt control syst, yaw damper › Malfunction
- Fluid › Contamination
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
With the autopilot engaged, and while climbing through approximately 5,000 feet msl, the pilot moved the heading bug 30 degrees to the right. The airplane then "sort of snapped with significant yaw," into a 60-degree right bank and lost about 1,800 feet of altitude. After recovering, the pilot continued to his destination. Examination of the airplane revealed that it was substantially damaged. Approximately five months prior to the accident, the autopilot system had been installed. Following the installation, the pilot experienced operational problems that included a "yaw problem" which began to worsen, but could not be duplicated by maintenance personnel. A postaccident examination of the autopilot and heading system also revealed no anomalies. Examination of the aft fuselage and tailcone revealed that the yaw damper was contaminated with oil. The source of the oil was an oil streak that ran from under the engine cowling aft along the belly of the airplane, and then up through the air conditioning exhaust vent. Two other airplanes which experienced yaw damper events were also examined, and oil contamination of the yaw damper amplifiers were identified.
Probable cause
A malfunction of the yaw damper system due to fluid contamination. Factors in the accident were the air condition exhaust vent design and the design stress limits of the airplane were exceeded.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record IAD05LA138
- Event ID
- 20050928X01541
- Case number
- IAD05LA138
- 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: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 0877fd996174f9b6e0e5d81964edbf23c0b37b8d456e7446774359493e8fdb7f; retrieved 2026-09-22T05:22:46.676Z.