N16CG

HISTORY OF FLIGHT

On May 1, 2001, approximately 1242 central daylight time, a Mitsubishi MU-2B-40, twin-engine turbo propeller driven airplane, N16CG, struck trees and terrain during an uncontrolled descent near The Woodlands, Texas. The airplane, co-owned by the pilot and passenger, was operated by the pilot under 14 Code of Federal Regulations Part 91. The commercial pilot and his passenger sustained fatal injuries, and the airplane was destroyed by impact forces and a post-impact fire. Visual meteorological conditions prevailed in the vicinity of the departure airport. An instrument flight rules (IFR) flight plan was filed for the personal cross-country flight which departed Conroe, Texas, at 1233, with a planned destination of Alamorgordo, New Mexico.

Witness interviews were conducted by the NTSB investigator-in-charge (IIC), FAA inspectors, and local authorities. One witness stated that "it did not seem as though the propellers were under power, but free and rotating. The rudder appeared to be in the opposite direction of the spin." Several other witnesses stated that one of the propellers was not turning. One witness reported hearing an engine "roaring."

One witness reported that "engine surges continued for three or four cycles then changed to an oscillating sound" Subsequently, this witness went into his house, and upon returning to the outside, recalled that the "oscillating sounds were louder and sounded like he still had power on."

One witness reported that at least one engine was running at high power and surging out of control. Another witness stated that "the engine would idle roughly, then accelerate extremely rapidly, then choke back down and idle roughly, then accelerate at full power again." One witness heard "the airplane engine revving up and idling down, not cutting out, and observed the airplane flying erratic, then enter a flat spin, and the right fuel tank was missing."

Several witnesses at a local construction job site reported that "the end piece of a wing" was missing.

Witnesses at a local practice football field heard "a loud buzzing noise that would cut in and out." The witness at a local football field, who had initially observed the airplane, reported that "the airplane was in a flat spin", and subsequently, other witnesses observed the airplane in a "vertical spin."

Another witness reported the airplane was in a "flat spin" and the right fuel tank was missing. This witness described the airplane as "trying to come out of the spin." Subsequently, the airplane "went into a flat spin again."

One witness, who was located in his back yard, heard an "unusual engine noise. The noise was repetitive with about a two second count between the loudest parts of the sound." This witness did not hear any stopping, starting, or stalling of the engines. This witness who observed the twin engine airplane at an estimated altitude of 4,000 feet, "spinning as though one wing was anchored and spinning about that point," stated that one of the wing tip fuel tanks and a portion of the wing outboard from the engine was missing. Further, this witness reported that when the airplane came out of the spin, the engine noise sounded normal.

Another witness heard "the sound of a turboprop feathering it's blades on and off." This witness observed the airplane at about "1,500 feet in a flat spin, nose 5 degrees down" until the airplane went below the tree line.

One witness, near the local golf course, reported that the airplane "appeared to be having engine trouble. The noise was very loud. The engine would idle roughly then accelerate extremely rapidly then choke back down and idle roughly then accelerate at full throttle again. This occurred at least a dozen times."

One witness at the local golf course described the sound like "engines out of sink." This witness observed the airplane in a right hand flat spin with the nose in a slight down position (10-20 degrees). According to this witness, the airplane made about 6 turns before it went behind the tree line.

Another witness observed the airplane approximately 600-800 feet above ground "spinning and tumbling end over end and falling at about 45 degrees" toward a creek.

One witness observed the airplane "in a circular motion, counterclockwise" as it disappeared behind the tree line.

PERSONNEL INFORMATION

A review of the FAA records by the NTSB IIC revealed that the pilot was issued his most recent FAA third-class medical certificate on January 24, 2000, with the limitation that he wear corrective lenses while acting as a pilot. The pilot held a commercial pilot certificate with the ratings and limitations of airplane multiengine land and instrument, and private privileges for airplane single-engine land.

According to the pilot's flight data supplied by the family, the pilot began flight training in September 1967, and in May 1969, he received his private pilot certificate with the airplane single-engine land rating. The instrument rating was added in December 1987, and the multiengine land rating was added in June 1991. The pilot obtained his commercial pilot certificate, in April 1992, with the airplane multiengine land and instrument ratings. In March 1994, the pilot began flying the MU-2 airplane. As of March 10, 2001, the pilot had accumulated 112.2 hours total flight time in the 12 months prior to the accident.

Approximately every 90 days during the 4 years prior to the accident, the pilot attended recurrent training at the facilities of Flight Safety International, Houston, Texas. From February 5, 2001, to the date of the accident, the pilot had accumulated 26.2 hours total flight time in the accident airplane. The pilot's most recent Mitsubishi recurrent simulator training was accomplished in April 2001 at the facilities of Flight Safety International, Houston. This training consisted of 15 hours of ground school and 6 hours of flight simulator time. According to these training records, dated April 26, 2001, the pilot had accumulated 2,839.1 hours total flight time of which 1,108.0 hours were in the Mitsubishi airplane (555.9 hours in N16CG).

Further, the training records indicated that the pilot had satisfactorily completed the training and testing requirements to act as pilot-in-command (PIC) of a Mitsubishi MU-2B-40 for CFR Part 91 operations. At the time of the accident, the pilot was returning from his latest recurrent training to his home base of operations. The Flight Safety personnel described the pilot as safety minded with good situational awareness, excellent checklist utilization, and professionalism in the piloting of the MU-2 airplane. They further stated that the pilot had good system and operational knowledge of the MU-2 airplane.

Interviews with immediate family members and acquaintances disclosed no evidence of any activities that would have prevented the pilot from obtaining sufficient rest in the 72 hours before the accident.

AIRCRAFT INFORMATION

Aircraft Registration Review

In July 1979, Mitsubishi MU-2B-40, serial number (SN) 418SA, was issued registration number N140MA (changed to N16CG on November 11, 1979). The FAA Standard Airworthiness Certificate was issued on November 9, 1979. At the time of the accident, the airplane was configured to carry seven passengers and one pilot.

The airplane history indicates that on September 24, 1981, the airplane was involved in a wing-to-wing ground collision in which substantial damage was incurred to the right wing from the wing-to-fuselage attachments and fuselage bell frames to the right tip tank. The aircraft was repaired and returned to service.

On January 4, 1991, the airplane was deregistered from the United States Civil Aircraft Registry for export to Caracas, Venezuela. Subsequently, the airplane was entered on the Venezuela registry as YV-11CP.

On December 21, 1995, the airplane was deregistered from the Venezuelan Register, imported to the USA, and re-entered on the United States Civil Aircraft Registry. On February 23, 1996, the FAA airworthiness certificate was re-issued for the aircraft, and it was purchased by Aberg, LTD, Rockford, Illinois. In October 1997, the airplane was purchased by Anaconda Aviation Corporation, Boca Raton, Florida. The airplane was registered to the current owners on October 23, 1997.

Maintenance Records Review

The FAA aircraft records, insurance records, pilot's computer records, and available maintenance records were reviewed by the respective manufacturer's representatives and the NTSB IIC.

Installed in each engine nacelle was a Honeywell (formerly Garrett) TPE331-10-511M engine. In 1989, the right engine, SN P37159, had accumulated 2,647.6 hours time since new (TSN), and the left engine, SN P36383C, had accumulated 864.8 hours TSN. According to engine service records, at the manufacturer's facility in Phoenix, Arizona, dated September 28, 1989, engine SN P-36383C received hot section and gearbox inspections at an engine time of 864.8 hours time since new (TSN) and 959 cycles since new (CSN) In December 1989, both engines were installed at zero time in the airplane by Intercontinental Jet, Inc., at Tulsa, Oklahoma. In June 2000, the 6 month, 12 month, 2 year, 100 and 500 hour inspections were performed at an accumulated airplane time of 2,439.1 hours. In February 2001, the left engine had accumulated 2,104.3 hours TSN (1,239.5 SMOH), and the right engine 3,887.1 hours TSN (1,239.5 SMOH).

Both engines had the Hartzell propeller model HC-B4TN-5 with LT10282NSB-5.3R blades installed. Prior to March 2001, the left propeller hub was SN CDA3189, and the right propeller hub was SN EAA1209M1. In February 1996, the blades for the right propeller were shot peened. Airworthiness Directive (AD) 83-08-01 (Service Instructions No. 140A) for torque sequence of bolts was complied with in July 1999, and the propellers balanced. In February 2001, ...