- Date
- August 25, 2006, 13:08 local (17:08 UTC)
- Place
- Bunnell, FL
- Injuries
- 2 fatal
- Damage
- Destroyed
- Phase of flight
- Enroute
- Aircraft
- N171MAMitsubishi MU-2B-40
- Weather
- Visual (VMC) · Day
- Status
- Completed · report September 27, 2007
- Report
- Approved by Office Director
- Parties
- Mitsubishi, FAA/FSDO, Honeywell Aerospace, Hartzell Propeller
- FAA report
- 20060825019959A
- Case key
- 64385
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
The pilot's inadvertent encounter with thunderstorms.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
The pilot had received an outlook briefing during the morning hours before the accident. The briefing included information regarding widely scattered thunderstorms and rain showers along portions of the pilot's planned route of flight. At the time of the accident, a convective weather significant to the safety of all aircraft (convective SIGMET) was in effect for the pilot's route of flight, and the information about the convective SIGMET was broadcast to the pilot by air traffic control (ATC). Several airplanes in the vicinity of the accident airplane were deviating around weather. Conversations between the accident pilot and the ATC controller were consistent with the accident airplane's weather radar functioning, and the possibility that the accident airplane's weather radar was providing more information than the ATC weather radar. Although the pilot initially declined a deviation query by ATC, he later accepted one. Shortly after, the pilot was unable to maintain his assigned altitude of 28,000 feet msl (FL 280), and the airplane impacted terrain consistent with a vertical descent. At the time of the accident, at FL 280, weak to moderate weather radar echoes existed. Very strong to intense weather radar echoes were seen about FL 200. The ATC facility was equipped with NEXRAD-derived weather displays. The weather displays had four settings: below FL 240, between FL 240 and FL 330, above FL 330, and from sea level to FL 600. At the time of the accident, the ATC controller's weather display indicated weak to moderate echoes above FL240. Very strong to intense weather radar echoes existed about FL200; however, the ATC controller did not have his weather display set to that altitude as he was not controlling traffic at that altitude. The investigation could not determine if the pilot was aware of the stronger intensity echoes below his altitude, or if the airplane's weather radar was depicting the stronger echoes. Examination of the wreckage did not reveal any preimpact mechanical malfunctions.
Factual narrative
History of flight
On August 25, 2006, at 1308 eastern daylight time, a Mitsubishi MU-2B-40, N171MA, was destroyed during an in-flight separation and impact with terrain near Bunnell, Florida. The certificated commercial pilot and passenger were fatally injured. Visual meteorological conditions prevailed near the accident site, for the flight that departed Monroe County Airport (KBMG), Bloomington, Indiana; destined for Governors Harbour Airport (MYEM), Eleuthera Island, Bahamas. An instrument flight rules flight plan was filed for the personal international flight conducted under 14 CFR Part 91.
At 1222, the pilot made initial contact with the Jacksonville, Florida, air route traffic control center (ARTCC). At that time, the airplane was at 28,000 feet msl (FL 280).
At 1241, the pilot was assigned a different radio frequency for Jacksonville ARTCC as the airplane entered a different sector of airspace. The pilot acknowledged and complied with the frequency change.
At 1251, several aircraft in the sector had deviated around convective weather via their own navigation, without assistance from the air traffic controller, except for obtaining approval for course deviations. The air traffic controller then asked the accident pilot if he was anticipating a need to deviate from course before reaching Ormond Beach, Florida. The pilot initially responded that no deviations would be needed.
At 1252, the controller broadcast an advisory for convective weather significant to the safety of all aircraft (convective SIGMET 39E), for the areas covering South Carolina, Georgia, Florida, and Florida Coastal waters. The pilot then advised the controller that he reconsidered a deviation, and inquired when he could proceed direct to MYEM. The pilot added that a deviation would depend on when he could go direct to MYEM. The pilot then asked if there was any possibility he could go direct to MYEM before reaching Ormond Beach, Florida. The controller responded that because of traffic, he needed the pilot to go to Ormond Beach before going direct to MYEM, and asked what deviation the pilot needed. The pilot responded that if he needed to deviate, it would be 10 degrees to the right, and wouldn't be needed for about 60 miles. The air traffic controller approved the deviation, and asked the pilot if he could make it back over Ormond Beach after the deviation. The pilot replied no, that Ormond Beach was under weather at the moment. The air traffic controller made a comment to the pilot about the accident airplane having better weather radar than he did. The air traffic controller then approved the deviation, and requested that the pilot advise when he could proceed direct to Melbourne, Florida. The pilot responded, "...Ten right now and direct Melbourne when able, I can handle that."
At 1306, the pilot reported to air traffic control (ATC) that he was unable to maintain altitude. The air traffic controller repeatedly attempted to contact the pilot, but no further radio communications were received from the accident airplane.
The accident occurred during the hours of daylight, located approximately 29 degrees, 18.80 minutes north latitude, and 81 degrees, 14.82 minutes west longitude.
Personnel information
The pilot held a commercial pilot certificate, with ratings for airplane multiengine land and instrument airplane. He also held a private pilot certificate, with a rating for airplane single engine land. The pilot's most recent FAA second class medical certificate was issued on May 2, 2006.
The pilot's logbook was not recovered; however, he had completed a "Pilot Information Form" on May 6, 2006, when he attended a flight school for recurrency training in his Mitsubishi MU-2B-40. According to that form, the pilot had accumulated a total flight experience of approximately 3,800 hours; of which, 3,400 hours were in multiengine land airplanes, and 1,700 hours in the same make and model as the accident airplane. The pilot also reported about 400 hours of actual instrument experience.
Aircraft information
The airplane was maintained under a manufacturer's approved inspection program (MAIP). The airplane's most recent inspection was completed on May 3, 2006. The inspection complied with a 100-hour/1 year and 200-hour/1 year inspection, in accordance with the Mitsubishi Maintenance Requirement Manual. During the inspection, corrosion was removed from the landing gear area and wing skin. At the time of the inspection, the airplane had accumulated approximately 3,802 hours of operation.
Meteorological information
About 0736, the pilot telephoned the Lansing, Michigan automated flight service station (AFSS). The pilot stated that he had a flight plan on file for a trip to Bloomington, Indiana, and continuing on. He then requested the outlook for Bloomington in 2 hours, and for South Florida in the afternoon, as he was heading to the Bahamas.
The weather briefer provided the pilot with advisories to Bloomington, the Bloomington forecast, and a forecast for South Florida. The forecast for South Florida included scattered clouds at 2,000 feet and 12,000 feet, with isolated thunderstorms and rain showers becoming widely scattered by 1400. The pilot indicated that he did not need any additional weather information.
At the time of the accident, convective SIGMET 39E was in effect for the route the pilot was flying. The convective SIGMET was for an area of thunderstorms moving 270 degrees at 15 knots, with tops to FL 450.
According to weather radar data, at FL 280, where the pilot reported that he was unable to maintain altitude, weak to moderate weather radar echoes existed. Very strong to intense weather radar echoes were seen about FL 200 (for further information, see Meteorological Factual Report in the public docket).
The reported weather at an airport about 8 miles east of the accident site, at 1250, was: wind from 100 degrees at 9 knots, gusting to 15 knots; visibility 10 miles; scattered clouds at 2,500 feet; scattered clouds at 5,000 feet; temperature 84 degrees F; dew point 71 degrees F; altimeter 29.89 inches Hg.
Wreckage and impact information
The main wreckage came to rest upright in a wildlife refuge, oriented about a 060-degree magnetic heading. Both wings had separated from the airframe, but remained attached to each other through the center wing section, and were located about 1/2-mile south of the main wreckage. The vertical stabilizer remained attached to the airframe, but the rudder had separated. The left and right horizontal stabilizers had separated; the left stabilizer was located near the main wreckage, and the right stabilizer was found near the wings.
The cockpit and cabin area were crushed, and imbedded several feet into the ground. No horizontal ground scars were observed near the main wreckage, consistent with a vertical impact. The landing gear was observed in the retracted position. Flight control continuity for the elevator and rudder were confirmed from the cockpit controls to their respective bellcranks near the point of separation. Left and right wing spoiler control continuity was confirmed from the cockpit to the wing center section (mixer). Rudder and elevator trim control continuity was confirmed from the cockpit, through four trim cables (two each), to the broom-straw separations near the rear of the airplane.
The wreckage was reexamined after the wings, engines, horizontal stabilizers, and rudder were recovered. The outboard section of the left wing had separated about 5 feet from the wing root, and the left wingtip fuel tank had also separated from the left wing. The outboard section of left wing and left wingtip fuel tank were found about 1/8-mile south of the right wing and inboard section of left wing. The left engine remained attached to the left wing, and was removed for examination. Due to impact damage,
Aircraft
- Registration
- N171MA
- Reported as
- Mitsubishi MU-2B-40
- Category
- Airplane
- Serial number
- 431 S.A.
- Airframe hours
- 3,802
- Engines
- Honeywell TPE331-10-551, 715 horsepower, turbo propHoneywell TPE331-10-551, 715 horsepower, turbo prop
- Damage
- Destroyed
- Flight
- Personal · Part 91
- Operator
- Ward T. Walter
- Registered owner
- Drug and Laboratory Disposal Inc.
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Continuous airworthiness · May 1, 2006
- Departed
- KBMG · Bloomington, IN
- Destination
- MYEM · Governors Harbo
- Flight plan
- IFR
- Airport
- NONE
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 65
- Injuries
- Fatal
- Certificates
- Private, Commercial
- Airplane ratings
- Single-engine land, Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Class 2, With waivers/limitations
- Last flight review
- May 1, 2006
- Seat
- Left
- Toxicology
- Performed
- Flight hours
- 3,800 total · 1,700 in this make and model
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 100° at 9 knots, gusting 15
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 84 °F, dew point 72 °F
- Altimeter
- 29.88 inHg
- Observed at
- OMN, 8 nm away
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.