History of Flight
On July 9, 2012, at 0937 mountain standard time, a Mooney M20L, registration N137MP, was substantially damaged during a hard landing followed by a loss of control at Scottsdale Airport in Scottsdale, Arizona. The flight instructor sustained serious injuries, and the pilot receiving instruction received minor injuries. The airplane was operated by the private pilot/owner under Part 91 of the Federal Aviation Regulations. No flight plan was filed for the local instructional flight, which had originated about 35 minutes prior. Visual meteorological conditions prevailed at the time.
The pilot/owner had purchased the airplane in Florida a few days earlier. He and the flight instructor flew it back to the Phoenix area, arriving 2 to 3 days before the accident. The purpose of the flight was to gain more experience in the newly acquired aircraft. The flight instructor reported that the pilot was practicing touch-and-go landings on runway 21. On the fifth landing, the pilot flared too high, causing the airplane to drop onto the runway and land hard. The airplane bounced back into the air, and the flight instructor directed a go-around. The pilot moved the power lever to full open and then moved his right hand to the flap handle, moving the flaps to the up position. Both the pilot and instructor reported that the engine “did not respond.”
The flight instructor pushed the nose down and attempted to level the wings to prevent a stall, resulting in the airplane impacting the ground in a fairly level attitude. After impact, the airplane veered off the left side of the runway. The instructor later inspected the wreckage and found the flaps in the full up position.
Two video cameras documented the accident. A study by the NTSB Vehicle Recorder Division showed that after the hard landing (about 500 feet from the runway threshold), the airplane reached an altitude between 24 to 37 feet. It then entered a left bank that increased to approximately 90 degrees. The left wingtip struck the ground, and the airplane cartwheeled, coming to rest upright but heading opposite the landing direction, about 1,330 feet from the initial touchdown point.
Personnel Information
The flight instructor held a commercial pilot certificate with single-engine land, instrument, and flight instructor ratings. He held a second-class medical certificate issued on January 26, 2011, and his most recent flight review was on November 4, 2011. He reported 6,397 total flight hours, including 5,066 hours of flight instruction.
The pilot receiving instruction held a private pilot certificate with single-engine land and instrument ratings. He reported approximately 1,400 total flight hours, with about 400 hours in Mooney aircraft. He had about 17 hours in the accident airplane since purchasing it a week prior. His most recent third-class medical certificate was issued on May 1, 2012.
Aircraft Information
The airplane was a single-engine, propeller-driven, four-seat Mooney M20L manufactured in 1988. Its maximum takeoff gross weight was 2,900 pounds. It was powered by a Continental IO-550-N engine rated at 310 horsepower, equipped with a McCauley 3-blade propeller.
The last annual inspection was on July 2, 2012. The airframe had 1,945 flight hours; the engine, installed in 2004, had accumulated about 123 hours since installation.
The wing flaps were electrically operated with push-pull tubes and bellcranks, with nominal travel of 0 to 33 degrees. The flap position switch was on the lower control console, and the indicator showed full up, takeoff (10 degrees), and full down. When the FLAPS UP position was selected, the flaps retracted fully unless the switch was returned to neutral. The Pilot Operating Handbook cautioned that pushing the switch to UP retracts flaps completely, and the go-around procedure specified setting flaps to takeoff position (10 degrees) before retracting fully.
Meteorological Information
At 0935, conditions at Scottsdale Airport (elevation 1,510 feet) included wind from 160 degrees at 4 knots, visibility 10 statute miles, clear skies, temperature 100°F, dew point 54°F, and altimeter setting 29.92 inHg. Density altitude was calculated at 4,594 feet.
Wreckage and Impact Information
The airplane came to rest about 1,830 feet from the runway 21 threshold and 200 feet left of the centerline, near taxiways B12 and B. The main landing gear had collapsed; the nose gear separated. Both wings were bent up about 30 degrees at roughly two-thirds span. The outer 4 feet of the left wing separated. The engine broke from its mounts but remained attached by wiring and hoses. Propeller blades were deeply scored, S-bent, and two blade tips separated.
The airplane had a Supplemental Type Certificate modification adding lower-profile inner gear doors. These doors were found ground down, and paint flecks matching their color were found near two parallel marks on the runway about 500 feet from the threshold, spaced similarly to the gear doors.
Tests and Research
A propeller manufacturer’s representative reviewed photographs of the blades and stated the damage was consistent with the engine operating at mid-range to high power at impact.
On July 12, 2012, an engine examination by NTSB, FAA, and engine manufacturer representatives found no anomalies preventing normal operation. Spark plugs showed normal wear, magnetos produced spark, cylinders exhibited good compression and continuity. A subsequent inspection on August 16-17, 2012, revealed that fuel injectors had two O-ring seals each instead of the specified one. However, bench flow testing indicated no significant difference in fuel flow due to the extra O-rings.