Accident Lancair IV-P N811HB,
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ASN Wikibase Occurrence # 14734
 
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Date:Tuesday 26 February 2008
Time:13:15
Type:Silhouette image of generic LNC4 model; specific model in this crash may look slightly different    
Lancair IV-P
Owner/operator:private
Registration: N811HB
MSN: LIV-311
Total airframe hrs:52 hours
Engine model:Experimental TCM TSIO-500-EXP
Fatalities:Fatalities: 0 / Occupants: 4
Aircraft damage: Substantial
Category:Accident
Location:French Valley Airport, Murrieta, CA -   United States of America
Phase: Initial climb
Nature:Private
Departure airport:Murrieta/Temecu, CA (F70)
Destination airport:Murrieta/Temecu, CA (F70)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
The pilot reported that the engine lost power while on approach for landing in the amateur-built experimental airplane. Unable to reach the airport, the pilot initiated a forced landing in hilly desert terrain resulting in structural damage to the airframe. Inspection of the modified engine revealed that it was equipped with an electronic ignition system consisting of two capacitive discharge modules with direct crank sensors. Two five-amp fuses in the electrical circuit for the ignition system were found blown. Inspection of the electrical system found no failures of the physical airplane wiring. The pilot, who built the airplane, stated that he designed the ignition system's electrical circuit with the intention of providing electrical redundancy to the ignition system. Examination and testing of the design as installed demonstrated that a minor voltage differential between the main and redundant power source created a condition that routed the current flow for both ignition sources through a single fuse, resulting in a single point of failure. According to the ignition manufacturer, the recommended wiring configuration that would allow ignition power redundancy did not include the addition of a common bus bar as was found on the accident airplane. The positioning of the automotive fuses on the firewall prevented the pilot from accurately identifying the electrical failure.
Probable Cause: A total loss of engine power while on approach due to the electrical overload of a fuse caused by the builder's inadequate design and installation of the electrical ignition system.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: LAX08LA066
Status: Investigation completed
Duration: 1 year and 2 months
Download report: Final report

Sources:

NTSB

Location

Revision history:

Date/timeContributorUpdates
27-Feb-2008 01:54 Fusko Added
27-Feb-2008 11:19 harro Updated
21-Dec-2016 19:13 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
21-Dec-2016 19:14 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
21-Dec-2016 19:16 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
21-Dec-2016 19:20 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
03-Dec-2017 09:34 ASN Update Bot Updated [Operator, Other fatalities, Departure airport, Destination airport, Source, Narrative]

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