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ASN Wikibase Occurrence # 183259
Last updated: 4 September 2019
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Date:07-JAN-2016
Time:15:40
Type:EROS 1600
Owner/operator:Private
Registration: N508AH
C/n / msn: 001
Fatalities:Fatalities: 1 / Occupants: 1
Aircraft damage: Substantial
Category:Accident
Location:Near Lebanon Municipal Airport (M54), Lebanon, TN -   United States of America
Phase: Take off
Nature:Private
Departure airport:Lebanon, TN (M54)
Destination airport:Lebanon, TN (M54)
Investigating agency: NTSB
Narrative:
The private pilot conducted a 20-minute local flight in the experimental, amateur-built airplane after installing a new ignition coil on the two-stroke, two-cylinder engine. He then returned to the departure airport, where he landed the airplane, back-taxied on the runway, and initiated a second takeoff. Witnesses reported that, shortly after takeoff, the airplane experienced a total loss of engine power. The airplane entered a left turn back toward the runway, then subsequently turned "sharply" left and descended to ground contact.

Examination of the airframe revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. Examination of the engine revealed that the front spark plug was burnt white, consistent with exposure to high temperatures or an excessively lean carburetor calibration. Although both front and aft carburetor adaptors exhibited degradation, the front cylinder adaptor exhibited significantly more damage and cracking compared to that of the aft cylinder. This likely resulted in additional air being ingested by the front carburetor, which subsequently resulted in a leaner fuel/air mixture in that cylinder. In addition, the front cylinder piston exhibited a hole about 1 centimeter in diameter, consistent with detonation/preignition. Records located in the pilot's hangar indicated that the pilot was servicing the engine with a fuel/oil ratio of 40:1, rather than the manufacturer-recommended ratio of 50:1.

It is likely that the use of an improper fuel/oil ratio resulted in carbon deposits in the front cylinder. Combined with the effects of the lean fuel/air mixture as a result of the degraded carburetor adaptors, the engine was susceptible to the development of detonation and/or preignition, which subsequently resulted in the development of a hole in the front cylinder piston head. As a result, the engine experienced a total loss of power, to which the pilot responded by attempting to turn back to the airport at low altitude. During the turn, the pilot allowed the airplane's airspeed to decay and exceeded its critical angle of attack, which resulted in an aerodynamic stall and collision with terrain.
Probable Cause: A failure of the front cylinder piston due to the pilot's improper maintenance, which resulted in a total loss of engine power after takeoff. Contributing to the accident was the pilot's decision to return to the runway at low altitude following the loss of engine power, and his failure to maintain adequate airspeed during the turn, which resulted in the airplane exceeding its critical angle of attack and experiencing an aerodynamic stall.

Sources:

NTSB: https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20160107X93631&key=1


Revision history:

Date/timeContributorUpdates
08-Jan-2016 07:34 gerard57 Added
08-Jan-2016 07:35 harro Updated [Aircraft type, Registration, Cn, Source]
08-Jan-2016 07:35 harro Updated [Date]
08-Jan-2016 18:46 Iceman 29 Updated [Embed code]
10-Jan-2016 17:08 Iceman 29 Updated [Source, Narrative]
23-Jan-2016 00:16 Geno Updated [Time, Location, Phase, Nature, Departure airport, Destination airport, Source, Damage, Narrative]
21-Dec-2016 19:30 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
19-Aug-2017 16:25 ASN Update Bot Updated [Time, Other fatalities, Nature, Departure airport, Destination airport, Source, Narrative]

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