Accident Lancair IV-P N5473,
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ASN Wikibase Occurrence # 44132
 
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Date:Wednesday 10 May 2006
Time:15:25
Type:Silhouette image of generic LNC4 model; specific model in this crash may look slightly different    
Lancair IV-P
Owner/operator:N5473 LLC
Registration: N5473
MSN: LIV-473
Total airframe hrs:27 hours
Fatalities:Fatalities: 2 / Occupants: 2
Aircraft damage: Destroyed
Category:Accident
Location:Somerset, PA -   United States of America
Phase: En route
Nature:Ferry/positioning
Departure airport:Somerset, PA (2G9)
Destination airport:
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
The experimental airplane had accrued 27 hours of total flight time, and had just completed its 25-hour Phase I flight testing period. Witnesses related that they saw the airplane engine start, and that the crew appeared to go through an extensive series of checks for approximately 10 minutes prior to takeoff. The engine idled smoothly, and was accelerated several times prior to taxi, once to full power. At takeoff, with a tailwind, the airplane accelerated smoothly, and rotated at a point along the runway that the witnesses thought was later than usual. The airplane pitched nose-up about 20 to 30 degrees in the climb, and the landing gear retracted. When the airplane reached treetop height, black smoke trailed from the engine exhaust system, and the engine "sputtered." The airplane entered a smooth roll to the left, yawed left, and then "plunged" to the ground, in a near vertical attitude. Witnesses said the turn after the loss of engine power was performed at a very high deck angle. Examination of data extracted from the airplane's electronic flight instrumentation system revealed that during the takeoff roll, the fuel flow was more than 20 percent above maximum, and the propeller was over-speeding. The engine rpm, fuel flow, and "Engine" warnings on the multi-function displays should have been visible to the crew. Examination of flight data revealed that the airplane continued to pitch-up as high as 22 degrees, as altitude decreased and airspeed decayed. Examination of the cockpit schematic revealed that the auxiliary fuel pump "high boost/low boost" switch was positioned next to the "Nav" lighting switch. In the airplane's "Before Takeoff" checklist, the "Lights-as required" task was to be performed four tasks prior to the "Takeoff" checklist.
Probable Cause: The pilot's failure to maintain sufficient airspeed after takeoff to preclude a stall, which resulted in a loss of control and an inadvertent stall. Factors associated with the accident are the inadvertent stall, the loss of engine power due to the pilot's inadvertent activation of the high pressure auxiliary fuel pump, and the pilot's failure to abort the takeoff after receiving abnormal engine and fuel flow warnings on the primary flight display.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: NYC06LA112
Status: Investigation completed
Duration:
Download report: Final report

Sources:

NTSB: https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20060522X00601&key=1

Location

Revision history:

Date/timeContributorUpdates
28-Oct-2008 00:45 ASN archive Added
21-Dec-2016 19:24 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
05-Dec-2017 09:11 ASN Update Bot Updated [Operator, Other fatalities, Departure airport, Source, Narrative]

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