Union Flights Piper PA-31-350 accident
Piper PA-31-350 · Accident: partial loss of engine power (non-mechanical) en route
From Flagstaff Pulliam Airport (FLG) to Phoenix Sky Harbor International Airport (PHX)
Event
- NTSB case
- LAX00LA043
- 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
- 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
- Visual Meteorological Cond
Piper PA-31-350
- 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
- N27181
- Operator
- Union Flights
- Onboard fatalities
- Unknown
- Route
- From Flagstaff Pulliam Airport (FLG), Flagstaff, AZTo Phoenix Sky Harbor International Airport (PHX), Phoenix, AZ
- 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
- En route · descent
- 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
- Partial loss of engine power (non-mechanical)
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Fuel starvation
- 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
- Pilot in command › Procedures/directives, not followed
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The airplane collided with a berm in a construction area after making an emergency landing. Following a flight of about 1.5 hours and after starting a descent, the pilot felt the left engine surge, and saw the left boost pump warning light flashing. The left engine continued to surge and the boost pump light remained fully illuminated. He chose not to feather the left propeller. He engaged both emergency fuel boost pumps and advanced the throttles and propellers for both engines. In this configuration the engines did not produce enough power to sustain flight. ATC identified two nearby airports for the pilot; one airport was 6 miles away and the other was 2 miles away. At 4,000 feet agl, the pilot felt he would not make either airport. According to the manufacturer's published emergency procedures, once an inoperative engine has been identified and an unsuccessful engine restart attempt is made, the pilot should feather the propeller. During the recovery, personnel noted that the inboard fuel tanks were full of fuel. Both outboard tanks were empty; however, fuel was found on the ground by one of the outboard fuel tanks. According to the operator, once a month the pilot's are encouraged to burn out the fuel in the outboard fuel tanks in VFR conditions. Following the accident, a functional check was conducted of the continuous duty fuel boost pumps and emergency fuel boost pumps. No discrepancies were noted. According to the pilot's operating handbook (POH), the continuous duty fuel boost pump warning lights will illuminate when pressure to the system drops below 3 PSI or the boost pumps have failed. Engagement of the emergency fuel boost pumps provides steady fuel pressure. The POH further reports that the fuel system has right and left fuel warning lights. The fuel flow warning lights illuminate to warn the pilot of an impending fuel flow interruption. These lights are located underneath the fuel boost pump warning lights. If the fuel level near the tank outlet drops to a point where a fuel flow interruption and power loss could occur, a sensing probe will illuminate its corresponding warning light. An inspection of the fuel system revealed that the system was intact and operated normally. The cross feed valves were operated and fuel was observed to flow to each engine from the opposite side wing fuel tank. No mechanical anomalies were noted.
Probable cause
The pilot's failure to follow the manufacturer's published emergency procedures for engine loss of power resulting in a forced landing in an open construction area where the airplane collided with a berm. A related factor was the loss of engine power in the left engine due to fuel starvation.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX00LA043
- Event ID
- 20001212X20259
- Case number
- LAX00LA043
- 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 1999-12-11.
- API snapshot SHA-256: 7fd26e33ddbdd32f8d72d394cf38b014f9179b1ac2e10c827f3f2e231896c4d6; retrieved 2026-09-18T16:50:39.905Z.