ROCK, KS, USA
N5LN
Mitsubishi MU-2B-60
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 926 flight hours in the B-90 airplane. In 1997 the pilot purchased N5LN, a MU-2B-60, s/n 799SA. He attended the Howell Enterprises, Inc. Initial Mitsubishi MU-2 Training Course which included ground school and flight training in August 1997. On August 27 and 28, 1998, he and the accident copilot attended FlightSafety International's MU-2 Pilot Recurrent Course located in Houston, Texas. The pilot's personal flight logbook indicated that on August 26, 1998, N5LN was flown from 3AU to HOU (Houston-William P. Hobby Airport). The flight lasted 2.2 hours. The logbook indicated the pilot received training in a simulator for 1.5 hours on August 27 and 1.5 hours on August 28. The pilot wrote in the Remarks section of his logbook that covered those two days the following statements: " *(un-legible mark) Jack Casey. SELdg-ADF, ILS, VOR approach. NTS (Negative Torque Sensing) air check." The pilots logbook indicated N5LN flew from HOU to 3AU on August 28, 1998. The flight lasted 2.2 hours. The pilot wrote in the Remarks section of his logbook that covered the flight the following statement: "air NTS check-rt. eng inop X10 min" The copilot held an airline transport pilot certificate with the ratings and limitations of airplane multi-engine land and a type rating in a Beech BE-300. He was commercially rated in single-engine land, and was a Certified Flight Instructor for multi-engine and single-engine land airplanes. He held a FAA first-class medical certificate dated July 7, 1998. The copilot was a simulator instructor pilot for FlightSafety International in Wichita, Kansas. He instructed in Beech 300 and Beech 350 simulators. According to an insurance application dated September 4, 1998, the copilot had accumulated about 22,770 total flying hours. He had flown about 420 hours in the make and model airplane in the last 5 years. He had flown the accident airplane about 16 hours in the last 90 days. The L. W. Aviation Flight Logs indicated the copilot flew with the pilot on August 26, 1998, from 3AU to HOU, and on the return flight to 3AU on August 28, 1998. AIRCRAFT INFORMATION The airplane was a twin engine Mitsubishi MU-2B-60, serial number 799SA. The airplane seated nine and had a maximum gross weight of 11,575 pounds. The engines were 715 horsepower AlliedSignal TPE-331-10 engines. The last 100 hour inspection was conducted on July 30, 1998. The airplane had flown about 30 hours since the last inspection and had a total time of 4,712 hours. On September 12, 1998, the airplane was flown from 3AU to Lakefront Airport (NEW), New Orleans, Louisiana, before its planned flight to the country of Belize in Central America, where the pilot had a personal residence. During takeoff from NEW to Belize, N5LN ingested a bird into the airplane's left engine. The airplane returned to NEW to assess the damage from the bird ingestion. The left engine was removed from the airplane for inspection and was subsequently overhauled. The left propeller was placed on a tire on the hangar floor when the left engine was removed from the airplane. A storm flooded the New Orleans area and the hangar where the airplane was parked. The watermark on the fuselage of the airplane indicated the water level in the hangar was about 18 inches deep. The left propeller was overhauled as a result of the water damage. The engine and left propeller were re-installed on the airplane on October 23, 1998. The October 23, 1998, engine logbook entry contained the following information: "Engine functional test c/w by Intercontinental Jet. Engine re-installation L/H side of MU-2B-60 s/n 799SA, N5LN. Ground run, rig, & leak check c/w. This engine requires soap sample within 25 hours. NTS test flight required before return to service." The L. W. Aviation Flight Log and Manifest indicated that the accident pilot flew the airplane from NEW back to 3AU on October 25, 1998. The mechanic from the fixed base operator where the airplane was hangared reported the pilot flew it by himself at night. The witness reported the pilot told him that he was not flying the airplane back to a maintenance facility, but that he was flying it back to Kansas, and later the accident copilot would fly it to a maintenance facility. The L. W. Aviation Flight Log and Manifest indicated that the accident copilot flew N5LN from 3AU to Tulsa International Airport (TUL), Tulsa, Oklahoma, on October 26, 1998, for required maintenance. Maintenance records indicated repairs were made to the landing gear system. The maintenance facility's Discrepancy Report form had the following entries: October 26, Discrepancy and BY: "Gear won't retract." October 28, Discrepancy and By: "OPS check of landing gear." October 28, Action Taken and By: "OPS checked L.G. after getting in water. Checked OK per maint manual." A witness at the maintenance facility reported the landing gear would not retract when the airplane arrived for maintenance on October 26, 1998. He reported the landing gear was thoroughly checked. He reported the airplane's "belly panels" were removed. He reported that no water was in the pressure vessel nor was there water in any of the belly panels. He reported both engines were run to compare the two. He reported that as a normal course of action an un-feather pump NTS check is performed during a ground engine run. The L. W. Aviation Flight Log and Manifest indicated the accident copilot flew N5LN back to 3AU from TUL on October 29, 1998. METEOROLOGICAL INFORMATION The November 4, 1998, surface weather observations at Wichita (KICT), Kansas, located about 28 nautical miles east-southeast of the accident site at an elevation of 1,321 feet, indicated the following: At 1956, the observation was ceiling 2,900 feet overcast; visibility 9 miles; temperature 4 degrees C; dew point 1 degree C; winds 360 degrees at 8 knots; altimeter setting 30.24 inches of Hg. At 2056, the observation was few clouds at 1,900 feet, ceiling 2,500 feet overcast; visibility 9 miles; temperature 4 degrees C; dew point 1 degree C; winds 020 degrees at 6 knots; altimeter setting 30.24 inches of Hg. At 2156, the observation was few clouds at 1,500 feet, ceiling 2,400 feet overcast; visibility 6 miles; mist; temperature 4 degrees C; dew point 2 degrees C; winds 010 degrees at 9 knots; altimeter setting 30.24 inches of Hg. The following AIRMET was in effect for the time and area of the accident: AIRMET Zulu Update 3 for ice (CHIZ WA 042045) issued November 4, 1998, 1445 and valid until November 4, 1998, 2100, occasional moderate rime or mixed icing in cloud and in precipitation above the freezing level to 15,000 feet. Freezing level surface to 4,000 feet. The upper air data indicated that at 2100 on November 4, 1998, the temperature at 2,034 feet was about 35 degrees F with a relative humidity of 89 percent. The temperature at 3,459 feet was about 30 degrees F with a relative humidity of 84 percent. The National Center for Atmospheric Research (NCAR) reported the Integrated Icing Diagnostic Algorithm (IIDA) for November 4, 1998, 2100, showed a high probability of potential icing (greater than 70%) from about 3,000 feet altitude to about 8,000 feet altitude in the KICT area. A second layer from about 9,000 feet to about 13,000 feet exhibited a high probability of potential icing. No Supercooled Large Drop (SLD) icing potential was indicated in the KICT area. According to NCAR, IIDA icing potential means that some supercooled liquid water exists. A high potential means that it is very likely that some liquid water exists there, but it is not an indication of icing severity. (See Meteorological Factual Report) WRECKAGE AND IMPACT INFORMATION The airplane impacted the ground in a flat, soft dirt field on a heading of about 082 degrees. A ground fire consumed the airplane's cockpit and much of the fuselage, and empennage. Fire and impact forces destroyed the cockpit instrumentation, avionics, annunciator panel and system controls. The main cabin door was found about 147 feet behind and to the left of the main wreckage. No fire damage was found on the main cabin door. Fuel spillage was observed over an area about 120 feet forward and 45 degrees to the left of the main wreckage. A positi
the pilot failed to maintain control of the aircraft and made an improper evaluation of the weather. Additional factors were flying a test flight at night with the icing conditions in the clouds.
Source: NTSB Aviation Accident Database
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