ANC95IA151

NTSB incident investigation · Piper PA-28-181 · Juneau, AK · August 26, 1995

Incident · No injuriesIncident investigationFinal report
Date
August 26, 1995, 09:45 local (17:45 UTC)
Place
Juneau, AK
Injuries
3 uninjured
Damage
Minor damage
Phase of flight
Enroute
Aircraft
N2937XPiper PA-28-181
Weather
Visual (VMC) · Day
Status
Completed · report April 18, 1996
Report
Approved by Office Director
NTSB office
Alaska Regional Office
FAA report
19950826032239I
Case key
2601

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

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Probable cause

failure and separation of the propeller blade due to foreign object damage and fatigue.

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Propeller failure/malfunctionClimb
Propeller system/accessories,blade - foreign object damageCause
Propeller system/accessories,blade - fatigueCause
Propeller system/accessories,blade - separation

Analysis

Just after takeoff the airplane began to vibrate. The pilot reduced the power and returned for an immediate landing. Examination showed that 6 inches of one blade had separated from the propeller. The separated piece was recovered, and metallurgical examination showed that the blade separated due to a fatigue crack emanating from a gouge associated with foreign object damage. The propeller blade material met the material and hardness specifications as prescribed by the manufacturer.

Factual narrative

On August 26, 1995, at 0945 Alaska daylight time, a wheel equipped Piper PA-28-181 airplane, N2937X, registered to and operated by Skagway Air Service of Skagway, Alaska, experienced a severe vibration during climbout from the Juneau Airport, Juneau, Alaska. The airplane returned to the Juneau airport. The air taxi flight, operating under 14 CFR Part 135, departed Juneau and the destination was Gustavus, Alaska. A company visual flight rules flight plan was in effect and visual meteorological conditions prevailed. The airline transport certificated pilot and the two passengers were not injured and the airplane received minor damage.

According to the operator, approximately 6 inches of one propeller blade separated from the propeller. As a result of the vibration, the alternator broke away from the engine case resulting in a small engine compartment fire.

The separated propeller tip was recovered. The propeller tip and propeller were sent the NTSB's Materials Laboratory Division for examination. The examination revealed that the area of the fatigue origin was a wedge shaped cavity on the leading edge of the blade. The cavity was oriented approximately 35 degrees to the leading edge of the blade and extended below the surface about 0.03 inch. The total length of the cavity (on both separated pieces) was approximately 0.25 inch. The composition and hardness of the material from which the propeller was manufactured was checked and found to meet the manufacturer's specifications.

According to a McCauley Service Letter 1995-4, dated February 10, 1995, it states that stress riser damage caused by stones or other small objects striking the propeller blade as it is rotating is the only damage that needs to be repaired in the field.

During a telephone conversation with the pilot, she said she did not see any nicks or gouges in the leading edges of the blades during preflight.

Aircraft

Registration
N2937X
Reported as
Piper PA-28-181
Category
Airplane
Serial number
28-7990567
Airframe hours
9,364
Engine
Lycoming O-360, 180 horsepower, reciprocating
Damage
Minor damage
Fire
On-Ground
Flight
Part 135
Registered owner
Skagway Air Service
Airworthiness certificate
Standard, Normal
Last inspection
100 hour · August 21, 1995 · 15 hours before
Departed
JNU · AK
Destination
GST · Gustavus, AK
Flight plan
Company VFR

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
25
Certificates
Airline transport, Flight instructor
Airplane ratings
Single-engine land, Multi-engine sea, Single-engine sea, Multi-engine land
Instrument ratings
Airplane
Medical
Class 1, Valid Medical--no waivers/lim.
Seat
Left
Flight hours
2,733 total · 150 in this make and model · 2,633 as pilot in command · 172 in the last 90 days · 91 in the last 30 days · 6 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
Calm
Visibility
99 statute miles
Lowest ceiling
None
Temperature
63 °F

FAA reports on this event · 1

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