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N5473 accident description

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Crash location 40.038889°N, 79.014444°W
Reported location is a long distance from the NTSB's reported nearest city. This often means that the location has a typo, or is incorrect.
Nearest city Somerset, PA
40.141738°N, 79.991440°W
52.1 miles away

Tail number N5473
Accident date 10 May 2006
Aircraft type Bulmer Lancair IV-P
Additional details: None

NTSB description


On May 10, 2006, at 1525 eastern daylight time, an amateur-built Lancair IV-P, N5473, was destroyed following an uncontrolled descent after takeoff from runway 7 at Somerset County Airport (2G9), Somerset, Pennsylvania. Both certificated commercial pilots were fatally injured. Visual meteorological conditions prevailed, and no flight plan was filed for the ferry flight conducted under 14 CFR Part 91.

The purpose of the flight was to deliver the airplane to its owner on the west coast; however, the planned stopover destinations could not be determined.

Several witnesses observed the accident flight, and their versions of the event remained consistent. According to the witnesses, the airplane engine started, and 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. The engine ran smoothly and without interruption throughout the pre-takeoff checks.

At takeoff, the airplane accelerated smoothly, and rotated at a point along the runway that 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, the engine "sputtered," and then stopped producing power.

The airplane entered a "smooth roll" to the left, yawed left, and then "plunged" to the ground, near vertically. The witnesses said the turn after the loss of engine power, was performed at a "very high deck angle."

The accident occurred during the hours of daylight approximately 39 degrees, 14 minutes north latitude, and 76 degrees, 31 minutes west longitude.


The pilot held a commercial pilot certificate with ratings for airplane single-engine land, and instrument airplane. The pilot had accrued 2,571 total hours of flight experience, with 500 hours in make and model. His most recent Federal Aviation Administration (FAA) second-class medical certificate was issued in October 2005.

The copilot held a commercial pilot certificate with ratings for airplane single engine land, multi-engine land, and instrument airplane. He also held a flight engineer certificate with a rating for turbojet airplanes. The copilot had accrued 5,585 total hours of flight experience. His most recent FAA third-class medical certificate was issued in December 2005.


Examination of the aircraft logbooks revealed that the airplane had accrued 27 total hours of flight time, and the most recent airworthiness inspection was completed on July 31, 2005. The 25-hour Phase I flight testing period, as prescribed by the Operating Limitations outlined by the FAA Manufacturing and Inspection District Office, New Cumberland, Pennsylvania, had just been completed.


At 1454, the weather reported at the Johnstown-Cambria Airport, Johnstown, Pennsylvania, 19 miles northeast, included visibility 10 miles, clear skies, and winds from 200 degrees at 8 knots. The temperature was 71 degrees Fahrenheit, and the dew point was 35 degrees Fahrenheit.


The airplane was examined and photographed at the site by FAA aviation safety inspectors, and all major components were accounted for at the scene. The initial ground scar was 50 feet beyond the departure end of the runway, and 200 feet left of centerline.

The airplane came to rest on its right side facing opposite the direction of travel. The nose, engine, cockpit, and cabin areas were destroyed by impact, and fragments of composite materials were scattered in a wide arc beyond the wreckage.

The engine came to rest inverted and displayed impact damage to the intake and exhaust tubes. The oil pan was crushed. The number 3 and number 5 cylinders displayed impact damage and appeared displaced.

The spark plugs were removed, and the electrodes were dark and soot covered.

The engine crankshaft was rotated by hand at the propeller, and continuity was confirmed through the powertrain, valvetrain, and accessory sections. Compression was confirmed on all but the number 5 cylinder, using the thumb method. The fuel pump ejected fuel when actuated. Field tests could not be completed on either magneto due to impact damage.

The engine examination was suspended, and the engine and its accessories were moved to an engine overhaul facility in Mattituck, New York, for further examination.


The engine was examined in Mattituck, New York, on August 22, 2006. A complete disassembly of the engine revealed no abnormal wear or mechanical deficiency.

Electrical power was applied to the auxiliary fuel pump and the motor ran at high rpm and pumped liquid at a constant rate.

The pump was forwarded to the manufacturer and bench tested. Test results revealed that the pump operated at the proper flow rates in both the high and low settings.

The airplane was equipped with a Chelton Flight Systems Electronic Flight Instrumentation System (EFIS).

FAA inspectors recovered the non-volatile memory from the EFIS, and forwarded it to Chelton Flight Systems for data recovery. The last flight, and four previous "power-ups" of the system, was recovered. No previous flights were recovered.

The data was then downloaded into a software program that re-created the accident flight on simulated primary flight and engine instrument displays, as viewed by the pilot.

Examination of the data revealed that the engine rpm and fuel flow limits were exceeded during the ground roll prior to takeoff. Once these limits were exceeded, the fuel flow peaked between 52 and 53 gallons per hour and remained there for the duration of the takeoff, the manifold pressure peaked and remained between 38.7 and 38.9 inches of Hg., while the propeller rpm fluctuated between 2,730 and 3,190 rpm.

The maximum rated propeller speed for the Continental TSIO-550-E was 2,700 rpm. The maximum fuel flow was 41.7 to 43.4 gallons per hour.

Examination of the flight data revealed that, early in the climb the airplane achieved positive climb rates of between 1,400 and 1,700 feet per minute, at speeds between 73 and 83 knots. Once the pitch-up attitude continued beyond 13.7 degrees, the positive climb rate diminished, and beyond 17.7 degrees, the airplane entered a descent, yet continued to increase nose-up pitch. The data showed that the airplane reached a maximum pitch-up attitude of 22.3 degrees, as it descended straight ahead for several seconds, while the propeller speed and fuel flow rate remained well above the maximum.

A review of the computer simulation revealed that during the takeoff roll, when the fuel flow exceeded the maximum, the fuel-flow needle and gauge, as well as the tachometer needle and gauge, flashed on the multi-function display. These events were followed immediately by an "Engine" warning illumination on the primary flight display.

According to the airplane's checklist, a normal takeoff was performed by a nosewheel "lift at 65 knots." Best angle of climb (Vx) was 110 knots with 10 degrees of flaps, and best rate of climb (Vy), was 135 knots with flaps retracted.

Examination of the data revealed that the airplane reached a top speed of 86 knots, at which point the rate of climb became a negative number. From that point, the airplane decelerated and descended until ground contact.


The Somerset County Coroner, Johnstown, Pennsylvania, performed autopsies on both pilots on May 11, 2006.

The FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicological testing on both pilots.


Examination of the cockpit schematic revealed that the auxiliary fuel pump "high boost/low boost" switch was positioned next to the "Nav" lighting switch on the instrument panel. According to the airplane's "Before Takeoff" checklist, the "Lights-as required" task was performed four tasks prior to the "Takeoff" checklist.

According to the aircraft checklist, auxiliary fuel boost pressure was only used above 10,000 feet for climb or cruise, and at the "Low" setting. "High" auxiliary fuel boost pressure was only used "momentarily" in the event of an engine failure, "to check for engine driven fuel pump failure."

(c) 2009-2018 Lee C. Baker / Crosswind Software, LLC. For informational purposes only.