Tuesday, November 19, 2019

Loss of Engine Power (Total): Aeronca 7AC Champion, N82694; accident occurred June 11, 2016 in East St. Louis, Illinois



The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entity: 
Federal Aviation Administration / Flight Standards District Office; St. Louis, Missouri

Aviation Accident Factual Report - National Transportation Safety Board:  https://app.ntsb.gov/pdf

Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms

http://registry.faa.gov/N82694

Location: East St. Louis, IL
Accident Number: CEN16LA218
Date & Time: 06/11/2016, 1736 UTC
Registration: N82694
Aircraft: AERONCA 7AC
Aircraft Damage: Substantial
Defining Event: Loss of engine power (total)
Injuries: 2 None
Flight Conducted Under: Part 91: General Aviation - Personal

On June 11, 2016, about 1200 central daylight time, an Aeronca 7AC airplane, N82694, experienced a complete loss of engine power and made an emergency landing on a closed section of newly constructed highway in East St. Louis, Illinois. The airplane sustained substantial damage to the tail section and wing struts during impact with a construction barricade. The pilot and passenger were not injured. The airplane was privately registered and operated under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which departed without a flight plan from Sackman Field Airport (H49), Columbia, Illinois, about 1145.

According to the pilot, about 15 minutes into the flight, he heard "a loud noise, a rattle" and the engine "seized." He decided to conduct a forced landing on a section of closed highway, however, the airplane was going too fast after touchdown to avoid the barricades at the end of the road closure. The wingtip impacted a barricade and caused a ground loop.

After the airplane was recovered, a Federal Aviation Administration (FAA) inspector and representative from Continental Motors examined the A-65-8 engine. There were two holes through the top of the crankcase, and cylinders No. 1 and No. 2 were separated from their mounts on the crankcase. Inside the No. 2 cylinder, the connecting rod was found fractured just below the piston head. The piston crown was still present inside the cylinder with a fragment of the connecting rod still attached by the piston pin. The longer portion of the connecting rod that was still connected to the crankshaft, extended outside the crank case hole. The No. 2 cylinder, including the piston crown and fragment of connecting rod, the longer portion of the connecting rod still attached to the crankshaft, and piston pin were examined at the NTSB Materials Laboratory, Washington, DC.

The materials examination found the fracture surface on the arm side of the connecting rod had been mostly obliterated, consistent with post-fracture impact damage. However, the piston crown side of the connecting rod had not been similarly damaged. This fracture surface of the rod exhibited features, such as crack arrest and ratchet marks, consistent with progressive cracking, later determined to be consistent with fatigue. The nature of the fatigue cracking features was consistent with stresses from reverse bending, originating in four distinct initiation sites at the connecting rod flanges. These initiation sites showed ratchet marks of varying sizes, consistent with smaller fatigue cracks that coalesced as they propagated inward. These cracks grew inward until the remaining rod cross section succumbed to overstress. The relatively large percentage of fatigue features on the fracture surface was suggestive of low-load or high-cycle fatigue.

The piston pin had fractured inside the connecting rod bore and was only discovered upon disassembly. The piston pin fracture location was between 1.37 and 1.59 inches from the shorter stub side. Most of the mating fracture surfaces exhibited smearing damage, consistent with continual rubbing while in contact inside the connecting rod bore. The fracture surfaces consisted of steps, generally oriented perpendicular to the pin forging direction. The surfaces were relatively flat, particularly around the outer regions. Examination of the fracture surface using a scanning electron microscope found two distinct regions of features on the fracture surface. The outer region, which extended to a depth of approximately 314 µm (0.012 inch), exhibited an intergranular fracture. The inner regions of the pin fracture surface exhibited dimple rupture, consistent with tensile overstress.

The pin microstructure was consistent with a resulfurized carbon steel that had been surface case hardened, such by carburizing or carbonitriding. The case hardened layer exhibited a depth of approximately 0.02 inch, consistent with the depth of the intergranular fracture features observed on the pin fracture surface.

The FAA issued Airworthiness Directive (AD) 46-36-01 which applied to all Continental Motors model A-65 engines. The AD outlined "a certain percentage of piston pins installed in engines of the above numbers and distributed as replacement parts are subject to failure without warning. The weakness of these pins cannot be detected by normal inspection methods. Piston pin breakage can result in complete engine failure." The AD required immediate compliance, if possible, but not later than 50 hours of engine operation after August 27, 1946. According to an engine logbook entry dated May 30, 2007, this AD was complied with on December 6, 1994. A second logbook entry, dated June 20, 2012, noted AD 46-36-01 was complied with "by piston pin replacement and piston inspection." The last annual inspection of the engine was completed on November 2, 2015, and noted the engine was "found to be in an airworthy condition for return to service."



Pilot Information

Certificate: Airline Transport; Commercial; Private
Age: 63, Male
Airplane Rating(s): Multi-engine Land; Single-engine Land
Seat Occupied: Front
Other Aircraft Rating(s): Glider
Restraint Used:
Instrument Rating(s): Airplane
Second Pilot Present: No
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 1 With Waivers/Limitations
Last FAA Medical Exam: 04/11/2016
Occupational Pilot: Yes
Last Flight Review or Equivalent: 08/05/2015
Flight Time: 22077 hours (Total, all aircraft), 61 hours (Total, this make and model), 7044 hours (Pilot In Command, all aircraft), 180 hours (Last 90 days, all aircraft), 60 hours (Last 30 days, all aircraft) 

Aircraft and Owner/Operator Information

Aircraft Make: AERONCA
Registration: N82694
Model/Series: 7AC NO SERIES
Aircraft Category: Airplane
Year of Manufacture: 1946
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 7AC-1336
Landing Gear Type: Tailwheel
Seats: 2
Date/Type of Last Inspection: 11/02/2015, Annual
Certified Max Gross Wt.: 1400 lbs
Time Since Last Inspection:
Engines:  Reciprocating
Airframe Total Time: 4095.95 Hours as of last inspection
Engine Manufacturer: Continental
ELT: Installed
Engine Model/Series: A65-8
Registered Owner: On file
Rated Power: 65 hp
Operator: On file
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KSTL, 710 ft msl
Distance from Accident Site: 14 Nautical Miles
Observation Time: 1751 UTC
Direction from Accident Site: 306°
Lowest Cloud Condition: Scattered / 5500 ft agl
Visibility:  10 Miles
Lowest Ceiling: Broken / 25000 ft agl
Visibility (RVR):
Wind Speed/Gusts: 7 knots /
Turbulence Type Forecast/Actual: 
Wind Direction: 250°
Turbulence Severity Forecast/Actual:
Altimeter Setting: 30.06 inches Hg
Temperature/Dew Point: 34°C / 18°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Columbia, IL (H49)
Type of Flight Plan Filed: None
Destination: Columbia, IL (H49)
Type of Clearance: VFR
Departure Time: 1145 CDT
Type of Airspace: Class D

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: 1 None
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 2 None
Latitude, Longitude: 38.616667, -90.133333 (est)

No comments: