CHI99FA023

The airplane's left engine had been overhauled and required an in-flight Negative Torque Sensing (NTS) check. The procedures required that the left engine be shut down during the test flight. The test flight was conducted at night. The pilots were briefed that there was icing and moderate rime icing mixed below 15,000 feet in clouds and precipitation. The cloud bases were between 2,500 to 2,900 feet agl. After departure, the pilot reported to ATC that they were clear and on top of the clouds at about 6,500 feet msl. N5LN was assigned a 180 degree heading at an assigned altitude of 8,000 feet. Without notification to ATC, N5LN turned to a southeast heading, descended from 7,700 feet to about 5,500 feet, and decelerated from about 182 kts to about 138 kts. ATC assigned N5LN a block altitude of 6,000 to 8,000 feet and a VFR-On-Top clearance. ATC instructed N5LN to turn right to stay in the assigned airspace. N5LN turned right but continued to descend from about 5,500 feet to the last radar indication of 4,500 feet. The airplane impacted the ground in a steep attitude. The inspection of the wreckage indicated the landing gear was down, and with full right rudder trim and about six degrees nose up trim. The examination of the engines indicated both engines were rotating and operating at the time of impact. The examination of the airframe and propellers found no pre-existing anomalies that would have precluded normal operation.

History of flight

On November 4, 1998, at 2058 central standard time (all times cst), a Mitsubishi MU-2B-60, operated by L. W. Aviation was destroyed when it impacted the ground near Rock, Kansas. The private pilot and an airline transport pilot certificated copilot received fatal injuries. The 14 CFR Part 91 flight departed Augusta Municipal Airport (3AU), Augusta, Kansas, on a local flight to conduct a maintenance test flight. Visual meteorological conditions prevailed and the flight had received a VFR-On-Top clearance.

At 2018, the pilot of N5LN requested a weather briefing for the 3AU area from the Federal Aviation Administration's (FAA) Wichita Automated Flight Service Station. The weather briefer said the cloud tops were at 8,200 feet mean sea level (all altitudes msl) in the area, and that there was icing and moderate rime icing mixed below 15,000 feet in clouds and precipitation. The pilot reported to the briefer that they needed to do some checks on the airplane and that they needed to determine whether to go on top or do the check beneath the ceiling. The pilot said they would be returning to the same airport. He then filed an IFR flight plan requesting 8,000 feet. The briefer said that he provided a standard briefing. The pilot said N5LN would be departing from 3AU and communicating with the Wichita Tower from the ground at 3AU.

N5LN, while still on the ground at 3AU, contacted the Wichita Air Traffic Control Tower, Flight Data position at 2034:16. N5LN reported they were an IFR flight staying in the area and requested 3,000 feet. Flight Data asked what N5LN needed to do, and then said, "I show you requesting eight thousand." N5LN replied that they wanted to stay in the area and do an engine-out test, and then land. Flight Data issued the clearance, "... via Augusta direct to Wichita direct, maintain 3,000 feet, expect 8,000 feet one zero minutes after departure, departure control frequency will be 134.8, squawk 4776, and hold for release." The pilot of N5LN repeated the clearance, and then asked the controller about radar vectors. The controller then said that they could expect radar vectors to stay in the area.

At 2035:35, N5LN reported to the tower that they were ready to depart on runway 36. At 2035:48, the controller issued the clearance, "...entering controlled airspace fly heading three six zero, released for departure, advise airborne 134.8."

At 2037:46, N5LN reported to the Wichita radar east controller that they were climbing to 3,000 feet. The controller acknowledged and told the flight to maintain 8,000 feet. The controller reported he was not receiving the transponder signal, and asked N5LN to recycle the transponder and push the transponder identification button. N5LN acknowledged at 2038:48.

At 2041:00, the radar data indicated that N5LN was about 6,300 feet and climbing at about 130 nautical miles per hour (kts) true airspeed (all speeds TAS), and on a heading of about 010 degrees.

At 2041:01, the controller reported the flight in radar contact six miles north of 3AU, and asked if the flight wanted to maneuver towards the VOR [Wichita].

At 2041:09, N5LN replied, "uh yes sir we could move maneuver a little bit away from the VOR will be fine we're just we're in uh we're in uh clear weather on top here now we're gonna shut down an engine to do an NTS check and then we'll be through."

At 2041:28, the controller asked the flight if it wanted to continue on a heading for the test. N5LN responded, "kay that'd be fine yea."

At 2041:29, the controller then told N5LN to continue on the present heading, and said "Wichita altimeter's three zero zero four."

At 2042:41, the radar data indicated N5LN was about 7,800 feet at about 147 kts and on about a 009 degree heading.

At 2043:40, the controller told N5LN to turn right and to fly heading one eight zero. At 2043:44, N5LN repeated the heading.

At 2043:40, the radar data indicated N5LN was about 7,500 feet at about 160 knots on about a 004 degree heading, and in about a 500 foot per minute (fpm) rate of descent.

At 2044:40, the radar data indicated N5LN was about 7,200 feet at about 152 kts on about a 189 degree heading, and in about a 150 fpm rate of descent.

At 2046:20, the radar data indicated N5LN was about 7,800 feet at about 190 kts on about a 189 degree heading, and in about a 0 fpm rate of climb.

At 2047:20, the radar data indicated N5LN was about 7,800 feet at about 203 kts on about a 188 degree heading, and in about a 150 fpm rate of descent.

At 2047:37, the radar data indicated N5LN was about 7,700 feet at about 185 kts on about a 177 degree heading, and in about a 400 fpm rate of descent.

The radar data indicated N5LN had maintained a southerly heading from 2044:37 to about 2047:37. N5LN then made a left turn to a southeasterly heading, and N5LN's airspeed decelerated from about 182 kts to about 138 kts. N5LN did not notify ATC of the heading change, and N5LN did not notify ATC of the change in airspeed.

While on the southeasterly heading between about 2047:37 and 2053:38, N5LN descended from about 7,700 feet to about 5,500 feet, with an average descent rate of 365 fpm. N5LN did not notify ATC of the altitude change.

At 2049:00, the radar data indicated N5LN was about 6,700 feet at about 158 kts on about a 153 degree heading, and in about a 750 fpm rate of descent.

At 2049:03, the controller asked N5LN if it wanted VFR-On-Top.

At 2049:07, the pilot replied, "...we'd like a block altitude for this testing, maybe from six to eight thousand."

At 2049:12, the controller transmitted, "...roger, maintain VFR-On-Top, altitude your discretion, VFR."

At 2052:00, the radar data indicated N5LN was about 5,900 feet at about 136 kts on about a 138 degree heading, and in about a 200 fpm rate of descent.

At 2052:49, the controller asked the pilot to take up a westerly heading to "keep you in my airspace."

At 2052:53, N5LN replied, "okay I tell ya we'd like be a very, very slow turn." Radar data indicated that at that time the mode C altitude was 5,800 feet, and the flight was descending.

There were no more transmissions from N5LN.

While in a right turn between about 2053:38 and 2056:09, N5LN descended from about 5,500 feet to about 4,500 feet, with an average descent rate of 395 fpm.

At 2053:00, the radar data indicated N5LN was about 5,800 feet at about 126 kts on about a 115 degree heading, and in about a 300 fpm rate of descent.

At 2054:00, the radar data indicated N5LN was about 5,200 feet at about 135 kts on about a 196 degree heading, and in about a 400 fpm rate of descent.

At 2055:00, the radar data indicated N5LN was about 5,000 feet at about 135 kts on about a 230 degree heading, and in about a 250 fpm rate of descent.

The last radar return was at 2056:10 and it indicated N5LN was about 4,500 feet on about a 245 degree heading.

The airplane impacted the ground about 5 miles east of Rock, Kansas, at coordinates N 37 degrees 27.745 minutes, W 96 degrees 53.663 minutes.

Personnel information

The pilot held a private pilot certificate with the ratings and limitations of an airplane multi-engine land, single-engine land and sea, helicopter, and airplane instrument pilot.

He held a FAA third-class medical certificate dated January 9, 1998. His medical records revealed a history of myocardial infraction and coronary artery disease that required bypass graft surgery in 1988 and aortic valve replacement surgery in 1992.

The pilot had accumulated about 3,136 total flying hours. He had flown about 298 hours in the make and model aircraft. He had flown about 29 hours in the accident airplane in the last 90 days.

The pilot was a medical doctor, but he also owned and operated L. W. Aviation. From about 1991 until the summer of 1997, L. W. Aviation operated a Beech King Air B-90. The pilot had accumulated about 92