ERA18LA033

NTSB accident investigation · Cessna 421 · Presque Isle, ME · November 22, 2017

Accident · Minor injuriesLimited investigationFinal report
Date
November 22, 2017, 18:45 local (23:45 UTC)
Place
Presque Isle, ME
Injuries
2 minor, 2 uninjured
Damage
Substantial damage
Phase of flight
Initial climb
Aircraft
N421RXCessna 421
Defining event
Initial climb: Fire/smoke (non-impact)
Weather
Instrument (IMC) · Day
Status
Completed · report July 23, 2019
Report
Approved by Office Director
NTSB office
Eastern Region Aviation
Parties
FAA/FSDO
FAA report
20171122019679A
Case key
96398

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

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Probable cause

The in-flight leakage of fuel from the fuel injection system's mixture shaft onto the hot turbocharger, which resulted in an in-flight fire, and the pilot's inability to see the runway due to reduced visibility conditions and conduct a successful landing.

Findings · 2

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Engine fuel and control: fuel controlling systemAircraft › Aircraft power plant · Damaged/degradedCessna 421C: 1 caseAll aircraft: 59 casesProbable cause
Ceiling/visibility/precip: low ceilingEnvironmental issues › Conditions/weather/phenomena · Contributed to outcomeCessna 421C: 2 casesAll aircraft: 190 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Analysis

After takeoff, the commercial pilot saw flames coming from the left engine nacelle area. He retarded the throttle and turned off the fuel boost pump; however, the fire continued. He then feathered the propeller, shut down the engine, and maneuvered the airplane below the clouds to remain in the local traffic pattern. He attempted to keep the runway environment in sight while drifting in and out of clouds. He was unable to align the airplane for landing on the departure runway, so he attempted to land on another runway. When he realized that the airspeed was decreasing and that the airplane would not reach the runway, he landed it on an adjacent grass field. After touchdown, the landing gear separated, and the airplane came to a stop. The airframe sustained substantial damage to the wings and lower fuselage. Examination of the left engine revealed evidence of a fuel leak where the fuel mixture control shaft inserted into the fuel injector body, which likely resulted in fuel leaking onto the hot turbocharger in flight and the in-flight fire. A review of recent maintenance records did not reveal any entries regarding maintenance or repair of the fuel injection system. The pilot reported clouds as low as 500 ft with rain, snow, and reduced visibility at the time of the accident, which likely reduced his ability to see the runway and maneuver the airplane to land on it.

Factual narrative

On November 22, 2017, about 1845 eastern standard time, a Cessna 421C, N421RX, was substantially damaged during a forced landing shortly after takeoff from Northern Maine Regional Airport (PQI), Presque Isle, Maine. The commercial pilot was not injured; two crewmembers, and one passenger sustained minor injuries. The airplane was operated by Fresh Air LLC under the provisions of Title 14 Code of Federal Regulations part 135 as an air medical flight. Day, instrument meteorological conditions prevailed, and an instrument flight rules flight plan was filed. The flight originated at PQI about 1840 and was destined for Bangor International Airport (BGR), Bangor, Maine.The pilot reported that the preflight inspection of the airplane and ground operations were uneventful. After taking off on runway 19, the pilot retracted the landing gear and turned off the landing lights. He then observed flames coming from the left engine nacelle. He immediately retarded the throttle and turned off the fuel boost pump; however, the fire persisted. He feathered the propeller, shut down the engine, and maneuvered the airplane below the clouds to remain in the traffic pattern at PQI. He attempted to keep the runway environment in sight while drifting in and out of clouds. He was unable to align the airplane for a landing on runway 19, so he attempted to land on runway 10. The pilot realized the airspeed was dropping and the airplane would not reach runway 10, so he landed in an adjacent field. After touchdown, the landing gear broke away and the airplane came to a stop in the grass. The PQI reported weather at 1848 included, overcast clouds at 1,400 ft and broken clouds at 800 ft, with 5 statute miles visibility in light snow and mist. The pilot reported that the clouds were at 500 ft with rain and snow at the time of the accident. An inspector with the Federal Aviation Administration responded to the accident site and examined the wreckage. The airplane came to rest in an upright position. The landing gear were separated, and structural damage to the wings and lower fuselage was evident. Initial examination of the left engine revealed soot on the nacelle louver vents and some localized white discoloration near the turbocharger area. Subsequent examination of the engine revealed soot and a darkening of the area below and behind the fuel injector system near the turbocharger. The top engine cowling, which exhibited paint bubbling and discoloration from exposure to intense heat, was placed over the top of the engine and the damage was consistent with the area above the fuel injector system. The fuel system was then pressurized with 40psi of air and the sound of escaping air was heard in and around the mixture control arm of the fuel injector system. A mixture of water/soap was sprayed on the area where air was heard, and bubbles were immediately observed. Other areas of the engine were also sprayed with the water/soap mixture and no other signs of leaks were observed. Thearea where the leak was observed was consistent with fuel dripping and being blown onto the hot turbocharger in flight. The fuel injector system was removed, and blue staining was observed in and around the mixture arm. A pressure check of the exhaust system was also conducted. No leaks were observed at any welds or joints. A review of the engine logbook entries did not reveal evidence of any recent maintenance or repair on the fuel injection system. An annual inspection was completed on June 2, 2017 and a 100-hr inspection was completed on September 13, 2017.

Aircraft

Registration
N421RX
Reported as
Cessna 421 (C)
Category
Airplane
Serial number
421C0264
Built
1977
Airframe hours
7,473
Engines
Cont Motor GTSIO-520-L, 375 horsepower, reciprocatingCont Motor GTSIO-520-L, 375 horsepower, reciprocating
Damage
Substantial damage
Fire
In-Flight
Flight
Part 135
Operator
Fresh Air LLC
Registered owner
Fresh Air LLC
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · June 2, 2017 · 18 hours before
Departed
PQI · Presque Isle, ME
Destination
BGR · Bangor, ME
Flight plan
IFR
Airport
PQI · Northern Maine Regional
Equipment
Stall warning system, Auto-pilot, Handheld GPS, Onboard weather

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
52
Injuries
Minor
Certificate
Commercial
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
Class 2, Without waivers/limitations
Last flight review
June 28, 2017
Seat
Left
Restraint
3-point
Flight hours
4,482 total · 3,620 in this make and model · 3,973 as pilot in command · 73 in the last 90 days · 29 in the last 30 days · 0 in the last 24 hours

Weather

Conditions
Instrument (IMC) · Day
Wind
310° at 3 knots
Visibility
5 statute miles
Lowest ceiling
800 ft broken
Temperature
34 °F, dew point 34 °F
Altimeter
29.81 inHg
Observed at
PQI

Docket · 5

The files NTSB released with the investigation on December 21, 2018, on NTSB’s docket system: statements, records, photos and specialists’ reports. 7.0 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.