December 16, 2002

Kerry Woods Velocity Crash Factual Report

N241KW

On November 23, 2002, at 1610 central standard time, an amateur-built Woods Velocity, N241KW, sustained substantial damage during a forced landing to a wheat field after a loss of engine power.  The pilot was not injured.  This was the 8^th or 9^th flight made by N214KW during a  two day period, and the 4^th or 5^th on this day.  The pilot reported that: During climb-out the aircraft performed as it had in previous flights, climbing at close to 1000ft/min and building oil temperature to the 225deg.F limit until the pilot reduced power and leveled off.  Previous flights had shown that the oil temperature would come down quickly once the power setting was reduced.  The pilot reduced power, but after a few minutes had passed, found that the oil temperature was not coming down and remained stable at 220deg. F which is at the high end of operational.  The engine was running smoothly, water temperature was down to ~180 degrees  and the EGT looked good.  The pilot continued south with a continuous cruise power setting with an altitude of ~500feet AGL.  Approximately 10 minutes into the flight, and with out warning, he lost engine power.  He decided to land with gear up, in a wheat field.   The actual landing was short of the wheat field in a hollow section of an alfalfa field.  The dip in the ground caused the aircraft to bounce after the initial landing and come down hard on its nosed before coming to rest.

The following report was generated by Keith Holm, manager at Powersport Aviation, after completing a post incident visual, electrical and mechanical inspection of Kerry Woods’ Velocity N241KW and its engine, a Powersport RE-215, serial #2.  The Powersport data logging computer successfully recorded the engine operating parameters during this fateful flight until it was shut down by the pilot after the forced landing.  The details presented below are written in the order in which they were inspected.  This document is a factual report and therefore will not make assumptions as to what may have happened, or in what order to cause the engine failure. 

Details:

Conclusion:

Powersport Aviation found, with the exception of the exhaust system, that all flight critical engine systems were functional after the incident.  We feel that there were no problems with the engine management systems, or the integration which powered them.  The engine is mechanically sound and will be re-built to remove the ground contamination caused by the off field landing.  The propeller speed reduction unit sustained no damage, and looks factory new.  We will work with the customer to insure that his next design/build of exhaust system will be as reliable as the prototype flown on Powersports RV-6A test aircraft.

            We regret that examination of the airframe did not point conclusively to one specific item or cause that shut the engine down.  There were many indications of excessive heat around the fuel system, heat which may have been over 400 degrees F.  Because we can not recreate the actual flight conditions/failures, we can only state that the broken exhaust and resultant heat was a likely contributor to the engine failure.  How that excessive heat may have played a role is strictly conjecture.  We recommend that all engine integrations incorporate some kind of temperature probe or alarm system placed in the vicinity of the exhaust to warn of potential danger.  The exhaust systems must also be designed and built to accommodate the differential expansion of each primary pipe, and be mounted so that no external forces affect its operation.

  The Following is the data was recorded by
Powersport's Multi-function Display Computer during the incident flight.

Figure 1 

This screen print taken from the data collection aboard N414KW on November 23 2002 shows the relationship between actual throttle position and engine RPM during the time when engine power was lost.

At 10734 the engine rpm dips to 4985, while the throttle remains the same. Engine power is lost at 10740, again with no change in throttle position.
At time 10758 and again at 10770 the pilot added throttle.
The throttle was returned to the idle stop at time 110786.
Engine rpm equals zero at time 10786

Figure 2

This graph shows the relationship between throttle position and fuel injector actuation.  The cursor is placed at the point when engine power was lost.  The lower graph illustrates that the engine management computers continued to send out actuating signals to the electronic fuel injectors until the power was switched off after landing.  The actual injection time (duration) is determined by the base fuel maps and other modifying maps such as air  temperature and barometric pressure and are accurate.