Portland Airport
Aircraft Accident/Incident Report

Portland, Oregon 97208
Tuesady, October 14, 2008 8:05 PDT

NTSB Narrative Summary Released at Completion of Accident

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.

NTSB Probable Cause Narrative

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.

Event Information

Type of Event Accident
Event Date 10/14/2008
Event Day of the Week Tuesday
Time of Event 805
Event Time Zone Pacific Daylight Time
Event City Portland
Event State OREGON
Event Country --
Zipcode of the event site 97208
Event Date Year 2008
Event Date Month 10
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 453519N
Event Location Longitude 1123551W
Event Location Airport Portland
Event Location Nearest Airport ID PDX
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness --
Investigator's weather source Weather Observation Facility
Time of the weather observation 753 Pacific Daylight Time
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID KPDX
Elevation of weather observation facility 30
Distance of event from weather observation facility (units?) --
Time Zone of the weather observation PDT
Lighting Conditions Day
Lowest Ceiling Height --
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions Few
Sky Condition for Lowest Ceiling Broken
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 11
Dew Point at event time (in degress fahrenheit) 9
Wind Direction (degrees magnetic) 300
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 3
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 30.46
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor --
Injury Total None 1
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 25761
NTSB Notification Source Ameriflight
NTSB Notification Date --
NTSB Notification Time --
Fiche Number and/or location -used to find docket information --
Date of most recent change to record Jul 22 2009 4:35PM
User who most recently changed record coos
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N3BT
NTSB Number WPR09LA013
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 135: Air Taxi & Commuter
Type of Flight Plan filed IFR
Flight plan Was Activated? No
Damage Substantial
Aircraft Fire In-flight
Aircraft Explosion None
Aircraft Manufacturer's Full Name PIPER
Aircraft Model PA-31-350
Aircraft Series Identifier --
Aircraft Serial Number 31-7752172
Certified Max Gross Weight 7000
Aircraft Category Airplane
Aircraft Registration Class --
Aircraft is a homebuilt? No
Flight Crew Seats 2
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 2
Number of Engines 2
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection AAIP
Date of Last Inspection Sep 30 2008 12:00AM
Airframe hours since last inspection 29
Airframe Hours --
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site No
ELT Type Unknown
Aircraft Owner Name UAS TRANSERVICES INC
Aircraft Owner Street Address 301 N LAKE AVE STE 600
Aircraft Owner City PASADENA
Aircraft Owner State CA
Aircraft Owner Country USA
Aircraft Owner Zipcode 91101-5129
Operator is an individual? No
Operator Name Ameriflight, Inc.
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address 301 N LAKE AVE STE 600
Operator City PASADENA
Operator State CA
Operator Country USA
Operator Zip code 91101-5129
Operator Code JIKA
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation --
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not Non-scheduled
Indicates Domestic or International Flight Domestic
Operator carrying Pax/Cargo/Mail Cargo
Type of Flying (Per_Bus / Primary) --
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code PDX
Departure City Portland
Departure State OR
Departure Country USA
Departure Time 800
Departure Time Zone PDT
Destination Same as Local Flt --
Destination Airport Code PDT
Destination City Pendleton
Destination State OR
Destination Country USA
Specific Phase of Flight --
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jul 22 2009 4:35PM
User who most recently changed record coos
Since inspection or accident --
Event Location Runway Number and Location N/A
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --