The National Transportation Safety Board did not travel to the scene of this accident.
Additional Participating Entities:
Federal Aviation Administration / Flight Standards District Office; Enfield, Connecticut
Continental Motors; Mobile, Alabama
Aviation Accident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf
Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms
Aviation Accident Data Summary - National Transportation Safety Board: https://app.ntsb.gov/pdf
http://registry.faa.gov/N98550
Location: Salisbury, CT
Accident Number: ERA17LA275
Date & Time: 08/13/2017, 1700 EDT
Registration: N98550
Aircraft: PIPER J3C
Aircraft Damage: Substantial
Defining Event: Powerplant sys/comp malf/fail
Injuries: 2 Minor
Flight Conducted Under: Part 91: General Aviation - Instructional
Analysis
During cruise flight, the airplane experienced a total loss of engine power, and the flight instructor performed a forced landing into trees. The engine crankshaft was replaced about 4 years and about 317 hours of operation before the accident. Teardown examination of the engine revealed that the crankshaft gear screws were fractured, and the crankshaft gear was separated from the crankshaft. Fretting was observed near two of the four crankshaft screw holes and corresponded to two elongated screw holes on the crankshaft gear. The crankshaft and crankshaft gear did not contain a dowel pin as specified in the most current versions of the manufacturer's illustrated parts catalog and overhaul manual, which were published more than 2 years before the crankshaft replacement. Additionally, the crankshaft gear did not contain a dowel pin hole, which was consistent with a crankshaft gear for an older, different model engine. Both publications contained numerous instructions and references to use a crankshaft gear with a dowel pin hole and to align the gear to the crankshaft with a dowel pin, which would pilot the crankshaft gear on the crankshaft. Thus, it is likely that when the crankshaft was replaced, maintenance personnel did not use the most recent manuals and installed a crankshaft gear for a different engine, which led to the crankshaft gear's failure and the subsequent loss of all engine power.
Probable Cause and Findings
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
An improper replacement of the crankshaft by maintenance personnel, which resulted in a failure of the crankshaft gear and total loss of engine power.
Findings
Aircraft
Recip eng rear section - Failure (Cause)
Personnel issues
Replacement - Maintenance personnel (Cause)
Environmental issues
Tree(s) - Contributed to outcome
Factual Information
On August 13, 2017, about 1700 eastern daylight time, a Piper J3C-65, N98550, operated by Berkshire Aviation Enterprises Inc., was substantially damaged during a forced landing into trees, following a total loss of engine power in cruise flight near Salisbury, Connecticut. The flight instructor and student pilot sustained minor injuries. The local instructional flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and a visual flight rules flight plan was filed for the flight that departed Walter J Koladza Airport (GBR), Great Barrington, Massachusetts, about 1640.
The flight instructor reported that he was providing an introductory flight to the student pilot in that particular make and model airplane. About 20 miles south of GBR at 2,800 feet mean sea level, the airplane experienced a total loss of engine power. The flight instructor took control of the airplane from the student pilot and positioned the carburetor heat to on. He also verified that the fuel selector was in the on position and the magneto switch was set to both, but the engine did not regain power. There were no suitable landing areas nearby and the flight instructor elected to perform a slow landing into treetops. The airplane subsequently collided with trees and came to rest nose-down entangled in the trees.
The airplane was equipped with a Continental Motors C90-8F, 90-horspower engine. The airplane's most recent annual inspection was performed on July 13, 2017. At that time, the airframe had accumulated 2,093 hours of operation. Review of the engine logbook revealed that maintenance records prior to 1994 were lost and a new engine logbook was created in June 1994, indicating that the engine was overhauled at a total estimated time of 1,300 hours. In October 2013, at 689 hours since major overhaul, the engine was disassembled and inspected after being involved in a previous accident (NTSB ID # ERA11LA379). During that work, the crankshaft was replaced per "Continental Overhaul Manual dated 1-1994." The engine had accrued about 317 hours from the time of the most recent crankshaft replacement, to the most recent annual inspection.
Examination of the wreckage by a Federal Aviation Administration inspector revealed substantial damage to the wings and fuselage. When the inspector rotated the crankshaft by hand, he was unable to confirm thumb compression to two cylinders or continuity to the rear accessory section.
A teardown examination of the engine was subsequently completed at the manufacturer's facility, under the supervision of an NTSB investigator. The examination revealed that the crankshaft gear screws were fractured, and the crankshaft gear was separated from the crankshaft. Fretting was observed near two of the four crankshaft screw holes and corresponded to two elongated screw holes on the crankshaft gear. The crankshaft gear contained an oil stain witness mark in an area that coincided with a dowel pin hole on the crankshaft; however, the crankshaft and crankshaft gear did not contain a dowel pin as specified in the most current version of the manufacturer illustrated parts catalog (IPC) and overhaul manual (OM). Additionally, the crankshaft gear did not contain a dowel pin hole, which was consistent with a crankshaft gear for a C65 engine and not a C90 engine. The manufacturer's most recent IPC and OM were published in August 2011, which was more than 2 years prior to the most recent crankshaft replacement in 2013. Both publications contained numerous instructions and references to use a crankshaft gear with a dowel pin hole and align the gear to the crankshaft with a dowel pin, which would pilot the crankshaft gear on the crankshaft.
History of Flight
Prior to flight
Aircraft maintenance event
Enroute-cruise
Powerplant sys/comp malf/fail (Defining event)
Loss of engine power (total)
Emergency descent
Off-field or emergency landing
Collision with terr/obj (non-CFIT)
Pilot Information
Certificate: Flight Instructor; Commercial
Age: 46, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Front
Other Aircraft Rating(s): None
Restraint Used: Lap Only
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): Airplane Single-engine
Toxicology Performed: No
Medical Certification: Class 2 Without Waivers/Limitations
Last FAA Medical Exam: 06/20/2016
Occupational Pilot: No
Last Flight Review or Equivalent: 12/22/2016
Flight Time: 1216 hours (Total, all aircraft), 263 hours (Total, this make and model), 1097 hours (Pilot In Command, all aircraft), 115 hours (Last 90 days, all aircraft), 42 hours (Last 30 days, all aircraft), 6 hours (Last 24 hours, all aircraft)
Student Pilot Information
Certificate: Student
Age: 59, Male
Airplane Rating(s): None
Seat Occupied: Rear
Other Aircraft Rating(s): None
Restraint Used: 3-point
Instrument Rating(s): None
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 3 With Waivers/Limitations
Last FAA Medical Exam: 04/06/2007
Occupational Pilot: No
Last Flight Review or Equivalent:
Flight Time: 100 hours (Total, all aircraft), 0 hours (Total, this make and model)
Aircraft and Owner/Operator Information
Aircraft Make: PIPER
Registration: N98550
Model/Series: J3C 65
Aircraft Category: Airplane
Year of Manufacture: 1946
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 18763
Landing Gear Type: Tailwheel
Seats: 2
Date/Type of Last Inspection: 07/13/2017, Annual
Certified Max Gross Wt.: 1220 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time: 2093 Hours as of last inspection
Engine Manufacturer: Continental Motors
ELT: Installed, not activated
Engine Model/Series: C90-8F
Registered Owner: JACOBS JIM J
Rated Power: 90 hp
Operator: BERKSHIRE AVIATION ENTERPRISES INC
Operating Certificate(s) Held: Commuter Air Carrier (135)
Operator Does Business As:
Operator Designator Code: BPGA
Meteorological Information and Flight Plan
Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: BDL, 173 ft msl
Distance from Accident Site: 25 Nautical Miles
Observation Time: 1651 EDT
Direction from Accident Site: 150°
Lowest Cloud Condition: Few / 5500 ft agl
Visibility: 10 Miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 9 knots / 14 knots
Turbulence Type Forecast/Actual: / None
Wind Direction: 320°
Turbulence Severity Forecast/Actual: / N/A
Altimeter Setting: 29.93 inches Hg
Temperature/Dew Point: 28°C / 14°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Great Barringto, MA (GBR)
Type of Flight Plan Filed: VFR
Destination: Great Barringto, MA (GBR)
Type of Clearance: None
Departure Time: 1640 EDT
Type of Airspace:
Wreckage and Impact Information
Crew Injuries: 1 Minor
Aircraft Damage: Substantial
Passenger Injuries: 1 Minor
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 2 Minor
Latitude, Longitude: 42.035000, -73.433889 (est)
NTSB Identification: ERA17LA275
14 CFR Part 91: General Aviation
Accident occurred Sunday, August 13, 2017 in Salisbury, CT
Aircraft: PIPER J3C, registration: N98550
Injuries: 2 Minor.
This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
On August 13, 2017, about 1700 eastern daylight time, a Piper J3C-65, N98550, operated by Berkshire Aviation Enterprises Inc., was substantially damaged during a forced landing into trees, following a total loss of engine power in cruise flight near Salisbury, Connecticut. The flight instructor and student pilot incurred minor injuries. The local instructional flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and a visual flight rules flight plan was filed for the flight that departed Walter J Koladza Airport (GBR), Great Barrington, Massachusetts, about 1640.
The flight instructor reported that he was providing an introductory flight to the student pilot in that particular make and model airplane. About 20 miles south of GBR at 2,800 feet mean sea level, the airplane experienced a total loss of engine power. The flight instructor took control of the airplane from the student pilot and positioned the carburetor heat to on. He also verified that the fuel selector was in the on position and the magneto switch was set to both, but the engine did not regain power. There were no suitable landing areas nearby and the flight instructor elected to perform a slow landing into treetops. The airplane subsequently collided with trees and came to rest nose-down entangled in the trees.
The airplane was equipped with a Continental Motors C90, 90-horspower engine. Examination of the wreckage by a Federal Aviation Administration inspector revealed substantial damage to the wings and fuselage. When the inspector rotated the crankshaft by hand, he was unable to confirm thumb compression to two cylinders or continuity to the rear accessory section.
The engine was retained for further examination.
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