Piper PA-31-350 accident near Portland, Oregon, October 14, 2008
On October 14, 2008 at about 3:05 pm local time, a Piper PA-31-350, registered N3BT, was substantially damaged in an accident during initial climb near Portland, Oregon (Portland airport). It was flown under charter and air-taxi rules (Part 135). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
An in-flight engine fire due to the fatigue fracture of an exhaust pipe that resulted from a failure of the pipe's slip joint.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 14, 2008 · about 3:05 pm local time
- Place
- Portland, Oregon · Portland · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Piper PA-31-350 · all PA-31-350s on the register
- Registration
- N3BT · no longer on the register · serial 31-7752172
- Damage
- Substantial damage
- Flight
- Flight · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that shortly after departure, and about 1,000 feet above ground level, she noticed that the left engine’s manifold pressure dropped about 6 inches below the right engine’s indications. The engine was surging, and she thought that the turbocharger had stopped operating. The left cylinder head temperature was reading 0 degrees, but all other gauges were normal. No smoke or flames were noticed as the pilot returned to the airport for landing without declaring an emergency or shutting down the engine. During taxi to the ramp, the engine lost power. Postflight examination revealed a broken exhaust pipe on the right side of the exhaust system, with evidence of a fire in the accessory section and a burned-through section of skin. Metallurgical examination disclosed that the aft exhaust pipe flange had cracked and fractured due to fatigue. Dimensional measurements of the flange wall thickness were within design limits. The hardness was as expected for the specified type 321 steel, indicating that bending stresses acting on the flange exceeded its design capability. The cracking occurred due to excessive stresses that developed from thermal expansion of the exhaust line and insufficient sliding action at the slip joints within the exhaust pipe system. Bending of the flange and subsequent fatigue cracking indicated that the slip joints had likely not been working properly for some time.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Powerplant sys/comp malf/fail during initial climb defining event
- Fire/smoke (non-impact) during initial climb
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine exhaust › (general) › Malfunction
- cause Aircraft › Aircraft power plant › Engine exhaust › (general) › Fatigue/wear/corrosion
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 1,500 hours in all
- Medical certificate: Class 2
- Seat: left
- Injury: no injuries
The aircraft
- Last inspection: approved inspection programme, September 30, 2008; 29 hours since
- Maximum gross weight: 7,000 lb
- Seats: 2
- Landing gear: retractable
- Engine 1: Lycoming TIO-540-J2B (piston); 0 hours total
- Engine 2: Lycoming LTIO-540-J2B (piston); 0 hours total
- Operator: Ameriflight, Inc.
The flight
- Departed from: PDX Portland OR at 3:00 pm
- Destination: PDT Pendleton OR
- Flight plan: IFR
Weather at the time
- Light: daylight
- Wind: from 300° at 3 knots
- Visibility: 10 statute miles
- Sky: broken clouds; a few clouds
- Temperature: 52°F (11°C), dew point 48°F (9°C)
- Altimeter: 30.45 inHg
- Observation at 2:53 pm from KPDX
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.