- Date
- June 8, 2008, 13:15 local (17:15 UTC)
- Place
- Battle Creek, MI
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Enroute
- Aircraft
- N159WMPiper PA-44-180
- Defining event
- Enroute-cruise: Powerplant sys/comp malf/fail
- Weather
- Visual (VMC) · Day
- Status
- Completed · report December 24, 2008
- Report
- Approved by Office Director
- Parties
- Federal Aviation Administration, Hartzell Propeller, Piper
- FAA report
- 20080608838749A
- Case key
- 68220
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
The in-flight separation of the tip of a propeller blade due to metal fatigue that resulted from an inadequate inspection and repair.
Findings · 4
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.
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
The twin-engine airplane sustained substantial damage due to a separated propeller blade tip impacting the airplane's nose during cruise. The tip separation exhibited signs of fatigue failure. Witness marks consistent with tool file marks made during a leading edge repair were found at the area of the origin of fatigue. According to maintenance information published by the propeller manufacturer, a 10x magnifying glass should be used to examine repairs to ensure damage, file marks, and any course surface finish are removed prior to returning the propeller back to service.. The airplane accumulated a total time of 1,997 hours.
Factual narrative
On June 8, 2008, at 1315 eastern daylight time, a Piper PA-44-180, N159WM, sustained substantial damage due to a separated propeller blade tip impacting the airplane's nose during cruise near Battle Creek, Michigan. The airplane landed without further incident at the W K Kellogg Airport (BTL), near Battle Creek, Michigan. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 instructional flight was not operating on a flight plan. The certified flight instructor (CFI) and the commercial pilot receiving dual instruction were uninjured. The local flight originated from BTL about 1230.
The flight was returning to BTL at the time of the accident. CFI's report, in part, stated:
A large BANG was heard and felt 8 to 10 miles south east of the
airport. At that point we scanned the gauges and saw no sign of
problems. When we looked out the windscreen; however we saw
a large depression in the nose section of the aircraft. Initially we
thought we had ... a bird strike.
N159WM was a 2002, Piper PA-44-180, which was a twin engine, four seat airplane with serial number 4496159. The airplane was powered by two Lycoming engines. Each engine drove its own Hartzell propeller. The propeller blade was a model FJC7666A-2R that was installed in a model HC-C2YR-2CLEUF hub assembly. The serial number of the blade with the tip separation was J73543.
The airplane accumulated a total time of 1,997 hours.
The outboard section of the remaining propeller blade was cut away and sent to the National Transportation Safety Board's Materials Laboratory. A Senior Materials Engineer examined the propeller section and produced Materials Laboratory Factual Report number 08-097. The report referred to repair data from the propeller manufacturer's website indicating that a 10x magnifying glass should be used to examine repairs to ensure damage, file marks, and any course surface finish are removed prior to returning the propeller back to service. The laboratory report, in part, stated:
Fatigue features emanated from a fatigue origin area located at the
leading edge near the flat side of the blade ... . ... Angled file marks
consistent with a leading edge repair were observed between the
leading edge and the flat side of the blade ... .
Aircraft
- Registration
- N159WM
- Reported as
- Piper PA-44-180
- Category
- Airplane
- Serial number
- 4496159
- Airframe hours
- 1,997
- Engines
- Lycoming LO-360-A1H6, 180 horsepower, reciprocatingLycoming O-360-A1H6, 180 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Instructional · Part 91
- Registered owner
- Western Michigan University
- Airworthiness certificate
- Standard, Normal
- Last inspection
- AAIP · May 1, 2008 · 47 hours before
- Departed
- BTL · Battle Creek, MI
- Airport
- BTL · W K Kellogg
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 · 2
As NTSB recorded them. NTSB leaves out names.
- Role
- Flight instructor
- Age
- 26
- Injuries
- None
- Certificates
- Flight instructor, Commercial
- Airplane ratings
- Multi-engine land, Single-engine land
- Instrument ratings
- Airplane
- Medical
- Class 1, Without waivers/limitations
- Last flight review
- February 1, 2007
- Seat
- Right
- Flight hours
- 650 total · 200 in this make and model · 580 as pilot in command · 114 in the last 90 days · 24 in the last 30 days · 1 in the last 24 hours
- Role
- Student pilot
- Age
- 26
- Injuries
- None
- Certificate
- Commercial
- Airplane ratings
- Single-engine land
- Instrument ratings
- Airplane
- Medical
- Class 1, With waivers/limitations
- Last flight review
- February 1, 2007
- Seat
- Left
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 220° at 15 knots, gusting 22
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 84 °F, dew point 72 °F
- Altimeter
- 29.88 inHg
- Observed at
- BTL, 10 nm away
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.