IAD01FA015

The pilot was conducting a post-maintenance test flight. An overhauled engine had been installed on the right side of the airplane, and both propeller assemblies had been subsequently re-rigged. Ground checks were satisfactory, although the right engine propeller idled 90-100 rpm higher than the left engine propeller. Test flight engine start and run-up were conducted per the checklist, with no anomalies noted. Takeoff ground roll and initial climb were normal; however, when the airplane reached about 100 feet, it stopped climbing and lost airspeed. The pilot could not identify the malfunction, and performed a forced landing to rough, hilly terrain. Upon landing, the landing gear collapsed and the engine nacelles were compromised. The airplane subsequently burned. Post-accident examination of the airplane revealed that the propeller beta valves of both engines were improperly rigged, and that activation of the landing gear squat switch at takeoff resulted in both propellers going into feather. The maintenance personnel did not have rigging experience in airplane make and model. As a result of the investigation, the manufacturer clarified maintenance manual and pilot handbook procedures.

History of flight

On November 24, 2000, at 1151 eastern standard time, a Beech King Air F90, N94U, was destroyed during a forced landing after takeoff from the Lynchburg Regional Airport (LYH), Lynchburg, Virginia. The airplane was consumed by a post-crash fire. The certificated commercial pilot and the certificated pilot-rated mechanic were not injured. Visual meteorological conditions prevailed for the flight that originated at Lynchburg, about 1150. No flight plan was filed for the post-maintenance test flight, conducted under 14 CFR Part 91.

According to the pilot, the test flight followed the installation of an overhauled engine on the right side of the airplane. Prior to the flight, all ground checks were satisfactory, and the only discrepancy noted was that, at idle, the right propeller indicated 90-100 rpm higher than the left propeller.

The airplane was subsequently released for flight, and the pilot determined that the rotation speed (Vr) was 97 knots. Prior to takeoff, he completed the engine-start and before-takeoff checklists with no anomalies noted. According to the pilot:

"We finished the pre-takeoff checklist - and centerline checks - and everything was nominal, all the way through Vr. Vr was Vmc plus 10 knots, about 95 knots. The call before Vr was 'Everything was normal, no master cautions, no segments.' We rotated and came off the ground very normally. We rotated at the normal point on the runway, about 1,500 or 1,600 feet down. We were at the right speed and the right distance at takeoff.

We showed a positive rate of climb and I reached for the gear handle. I couldn't get it up because it was on that lousy down latch. At that point we were 100 feet off the ground and I sensed a loss of thrust. I pitched to the blue line, but we weren't climbing. I looked at the gauges and everything was normal but we were not climbing."

The pilot determined that the airplane would not fly, and selected a forced landing area to the left and just beyond the departure end of the runway. He completed the forced landing, and both occupants egressed the airplane without injury.

The pilot was asked to describe the engine instrument readings during the takeoff and after he perceived the apparent loss of thrust. According to the pilot:

"I looked at temperature and prop - everything was matched. The aircraft came off with no yaw and I pitched down to blue line. I reached to select the landing gear up and the landing gear would not come up. My conclusion was that the safety latch was holding it down. When I felt the loss of power, I felt no particular yaw because of the autofeather and the rudder boost.

The temperature and torque indicated I had power, but I clearly was not climbing. Both appeared normal and I did not see a split in values. I did not see N1, I just don't remember. I was sure I had a catastrophic failure, but I couldn't verify which side. We were not gaining altitude, we were bleeding airspeed, and I tried three times to get the gear up."

When asked if he heard the stall warning horn, the pilot said that he had, and that he then lowered the nose of the airplane. As soon as he lowered the nose, the horn went away.

The mechanic also reported that the inspections and ground runs were completed with only the 100-rpm difference in the idle speeds between the two engines. When interviewed, the mechanic said:

"We started the aircraft and taxied down to the runway. We went through the checklists, checked the props, and were waiting on the tower. We took the runway and I visually verified we had 800 pounds of fuel per side.

[The pilot] pushed the power levers forward and all the needles matched and looked okay. I watched the airspeed and Vr was about 95 to 100 knots. We came off the runway very quickly in under 2,000 feet. Everything seemed normal.

[The pilot] reached to select gear up, and something didn't feel right. He said, 'We've got a problem'. I knew something was wrong but I couldn't put my finger on it.

We were not climbing. We were too low, too slow, and we were not going to make it back. I just felt that we were not climbing like we should. I don't remember any engine noises like the engine spooling down. Just this feeling that we were sinking in."

In a written statement, the mechanic said:

"The engine start-ups were normal. We requested and received clearance to taxi to runway 4. While taxiing to runway 4 [the pilot] engaged the reverse mode and then brought the controls back out of 'reverse'. Also during taxi the entire checklist was read by me to [the pilot], with [the pilot] verbally responding as he accomplished each item that had been read. Upon reaching the approach end of runway 4, [the pilot] called the tower again and stated that we were ready to depart, with the tower clearing us for takeoff. While taking the active runway I looked at the fuel quantity gauges verifying that we had 800 lbs. of fuel per side.

Upon taxiing into position [the pilot] applied power and I visually verified both torque's and RPM were both coming up evenly and together. The takeoff roll was normal in all aspects with rotation occurring between 95 and 100 knots and well within the first 2000 feet of the runway. Our climb out was normal with no annunciator lights appearing and no abnormal engine sounds. Upon reaching approximately 200 to 300 feet off of the ground, [the pilot] selected the "gear up" position, after which I recall him stating, "We have a problem." At about that same time I felt that something was wrong with the aircraft. It felt as if we were slowing down (airspeed) and I could definitely tell that we were not climbing, as we should. (At no time did I feel a yaw in any direction, although at or around the time that [the pilot] selected "gear up" a slight left roll was noticed, but immediately corrected for.)"

In a written statement, one witness said he was watching aircraft arrive and depart the Lynchburg airport and that he was monitoring the tower frequency on a hand-held transceiver. He said:

"At the time of the incident I witnessed the King Air lift off from the runway. While I admittedly know very little about turbine-powered aircraft it seemed apparent right away that the pilot was experiencing a problem. The plane seemed like it was not accelerating and it was not gaining altitude.

The sound from the engines seemed louder than what I have heard before while watching other King Airs lift off. The gear was still down and the wings started rocking back and forth about 10 to 15 degrees. Shortly after lift-off I heard the pilot call the tower and declare an emergency. Shortly after the pilot declared, I lost site of the plane just past the end of the runway. A few seconds later I saw a large column of smoke and immediately drove my car to the crash site... [The pilot] stated that he didn't know what happened but thought the engines might have been 'over-torqued'."

The accident occurred during the hours of daylight at 37 degrees, 20 minutes north latitude, and 079 degrees, 12 minutes west longitude.

Personnel information

The pilot held an airline transport pilot certificate with ratings for airplane single engine land, multiengine land, and instrument airplane. He held a flight instructor certificate with ratings for airplane single engine land, multi-engine land, and instrument airplane.

The pilot's most recent Federal Aviation Administration (FAA) second-class medical certificate was issued February 2, 2000. The pilot reported 12,000 hours of total flight experience, 5,000 hours of multi-engine experience, and 250 hours of experience in make and model.

Aircraft information

The airplane was a 1981 Beechcraft Model F90 King Air, with 6,788 aircraft hours. Two Pratt and Whitney PT6 gas turbine engines powered the airplane. The engines drove two Hartzell constant-speed controllable-pitc