MIA99FA188

The pilot received a preflight weather briefing and was advised of thunderstorms with tops to 45,000 feet along a portion of the route of flight. En route, the pilot was advised of significant areas of heavy precipitation to which the pilot responded, 'uh roger one nine whiskey it looks like on our radar here that uh we go straight ahead we'll be all right there.' The flight was cleared to descend to 11,000 feet and the pilot requested deviation to the right for weather avoidance. The pilot made several routine radio communications while descending at a calculated average rate of descent of approximately 2,571 fpm before encountering adverse weather. During this time while descending, the calculated calibrated airspeed increased from approximately 190 knots to approximately 265 knots (the design dive speed Vd). The flight encountered a level 5 weather echo then began a high rate of descent. Both horizontal stabilizers with elevators and both outer portions of both wings failed in a down direction. Examination of the flight control cables, fracture surfaces of the wings and horizontal stabilizers, engines, and propellers revealed no evidence of preimpact failure or malfunction. The pilot did not request pilot reports. The design maneuvering speed of the airplane is 169 knots indicated; the POH indicates to slow to this speed for turbulence penetration.

History of flight

On June 25, 1999, about 1014 central daylight time (all times central standard time), a Beech C90, N3019W, registered to Aerocenter, Inc., experienced in-flight structural failure near Munson, Florida. Instrument meteorological conditions prevailed at the time and an instrument flight rules (IFR) flight plan was filed for the 14 CFR Part 135 nonscheduled, domestic, passenger/cargo flight. The airplane was destroyed and the airline transport-rated pilot and one passenger were fatally injured. The flight originated approximately 0836 from the Zephyrhills Municipal Airport.

The flight departed under visual flight rules (VFR) and according to a chronological summary of communications with Tampa Air Traffic Control Tower (Tampa ATCT), at 0836, the pilot contacted Tampa Approach Control requesting IFR clearance to Brookley Field Airport. The flight was cleared to the Brookley Field Airport, and the final clearance was to climb and maintain 12,000 feet. Air traffic control communications were transferred to the Jacksonville Air Route Traffic Control Center (Jacksonville ARTCC). The flight continued and according to a transcription of communications, the flight was cleared to 14,000 feet, then at 0852:34, the flight was cleared to climb to 18,000 feet. Air traffic control communications was transferred to another sector in the Jacksonville ARTCC. At 0904:07, the controller stated, "and king air three zero one nine whiskey I'm depicting uh significant areas of heavy precipitation from about uh thirty miles south of panama city and it extends to about uh twenty east of panama city and they extend northeast bound almost to the seminole vortac...." The pilot responded, "uh roger one nine whiskey it looks like on our radar here that uh we go straight ahead we'll be all right there." The controller acknowledged the pilot's transmission; communications were transferred to Tyndall Approach Control. At 0933:41, the controller cleared the flight direct to the DEFUN intersection, then Crestview, then to the destination airport; this communication was acknowledged by the pilot. The flight remained in contact with Tyndall Approach Control until 0953:28, when air traffic control communications were transferred to the Jacksonville ARTCC. The pilot advised the Jacksonville Air Route Traffic Control Center controller that the flight was at 18,000 feet which was acknowledged by the controller. At 0954:25, the controller stated, "and king air one nine whiskey after crestview you're cleared uh loxly then brookley", which was acknowledged by the pilot. At 1004:18, the flight was cleared to descend to 16,000 feet which was acknowledged by the pilot. The pilot was also provided the Crestview altimeter setting of 30.02 inHg. At 1007:19, the controller broadcast on the same frequency, "attention all aircraft hazardous weather information convective sigmet uh three three eastern and six two central valid on hiwas flight watch or flight service station." At 1009:33, the controller cleared the flight to descend and maintain 11,000 feet, which was acknowledged by the pilot. At 1010:14, the pilot was advised to contact Pensacola Approach Control.

According to a transcription of communications with Pensacola Approach Control, at 1011, the pilot contacted the facility and advised that the flight was descending to 11,000 feet. The controller acknowledged the pilot's transmission and advised the pilot that the Pensacola altimeter setting was 30.01 inHg. The pilot repeated the same altimeter setting and at 1012:39, the pilot advised the controller, "king air three zero one niner whiskey would like to deviate about ten to fifteen degrees to the right for weather." The controller responded at 1012;44, "king air one niner whiskey approved when able direct brookly", to which the pilot responded "alright." At 1013:52, a broadcast from an unknown source indicates, "three thousand outta control and going down." An unintelligible communication from an unknown source was recorded at 1013:54. There were no further recorded communications from the pilot of the accident airplane.

Review of the chronological summary and transcription of communications from the first air traffic control (ATC) contact with Tampa Approach Control, to the last contact with Pensacola Approach Control revealed there was no record that the pilot requested pilot reports.

Three witnesses who were located near the accident site reported hearing a "whistling" sound, followed by a "boom" sound; a piece of the airplane landed in a tree near their position. Another witness reported hearing two loud "booms" but never saw the airplane. One witness who was located at Krul Lake reported observing the airplane circling the lake area two or three times and heard a strange noise coming from the airplane, followed by two loud "booms."

The main wreckage was found inverted at the edge of a wooded area with segments of both wings attached.

Personnel information

According to FAA records, the pilot was the holder of an airline transport pilot certificate and commercial pilot certificate with ratings airplane multi-engine land, and single engine land, respectively. He was the holder of a second class medical certificate dated September 16, 1998, with the limitation to wear corrective lenses. The records also indicate that on August 12, 1998, he passed his oral examination associated with the annual flight test but mechanical malfunction during the flight test caused cancellation of the flight. The pilot failed the flight portion of the annual flight test on August 14, and again 4 days later. He passed the annual flight test on August 26, 1998. On February 22, 1999, he passed the equipment test oral examination and also the semi-annual instrument proficiency flight test required by Title 14 Code of Federal Regulations (CFR) Part 135.297.

According to paperwork located in the wreckage, as of April 1, 1999, the pilot had accumulated 7,000 plus total flight hours, 3,000 plus of which were in single engine airplanes and 4,000 plus hours were in multi-engine airplanes. He indicated a total of 500 plus hours in turbopropeller airplanes, 6,000 plus hours in cross-country flights, 1,000 plus hours at night, and 1,000 hours plus in night cross-country flight. Additionally, the paperwork indicated that he had attended Flight Safety November 6 through November 11, 1995, to attend the C/E 90 Initial Course.

Aircraft information

The aircraft total time at the time of the accident was approximately 3, 965 hours. The left and right engines had accumulated approximately 265 and 504 hours respectively, since major overhaul. The airplane was equipped with weather avoidance radar and a storm scope.

Review of the airplane maintenance records revealed an entry dated October 30, 1997, indicating that washer impressions in the left and right upper aft wing bolt fittings and on the left lower inboard spar cap were "dressed out". An entry dated April 14, 1999, indicates in part that 200-hour torque check of the left and right wing lower forward bolts was accomplished. Also, as a result of the inspection of the aft bulkhead and the horizontal stabilizer aft spars, installation of a shim was installed in accordance with instructions from Raytheon Aircraft Services. An entry dated May 19, 1999, indicates replacement of the wing bolts in accordance with 15-year replacement schedule. The supporting documentation indicates that depressions in the right lower aft outboard bathtub fitting were dressed and the left lower aft outboard bathtub fitting was replaced due to washer impressions and necking down of the bore. The pilot's and co-pilot's altimeters were signed off as being tested in accordance with 14 CFR Part 91.411(A), on April 7, 1999; the transponder was signed off as being tested that same day. The airplane's weather radar indicator was removed and sent to Honeywell