N72141 – Beechcraft (Textron Aviation) A36 – 1998-05-12 NTSB Accident Report

HISTORY OF FLIGHT

On May 12, 1998, at 1057 Eastern Daylight Time, a turbine-powered Beech A36, N72141, was destroyed after an in-flight breakup during cruise flight near Davis, West Virginia. The certificated private pilot-owner and three passengers were fatally injured. Instrument meteorological conditions prevailed at the time, and an instrument flight rules flight plan had been filed for the flight from Buffalo Niagara International Airport (BUF), Buffalo, New York, to Moore County Airport (SOP), Southern Pines, North Carolina. The personal flight was conducted under 14 CFR Part 91.

The airplane had earlier departed Hamilton Airport (CYHM), Hamilton, Ontario, at 0730, and arrived in Buffalo at 0800, with only the pilot onboard. The pilot passed through U.S. Customs, then had the main fuel tanks topped off with 20 gallons of fuel. Afterwards, the pilot and passengers boarded the airplane, which departed Buffalo, at 0938. The airplane climbed to 13,000 feet, and proceeded southbound, toward its destination.

At 1054:04, after being advised to look out for traffic, the pilot stated, "I'm in the clouds." At 1055:43, the pilot acknowledged the altimeter setting. At 1058:43, the air traffic controller asked that the pilot recycle the airplane's transponder, but no answer was received.

The accident occurred during daylight hours, and the last secondary radar returns occurred at 39 degrees, 07.6 minutes north, 79 degrees 27.5 minutes west, less than 1/2 nautical mile east of where the main wreckage was located.

PERSONNEL INFORMATION

The last entry in the pilot's logbook, on April 3, 1998, indicated that the pilot had 1,478 hours of flight time. A maintenance record, dated April 29, 1998, listed the airplane's total flight hours at 2,233.9, while the tachometer reading at the accident site was estimated to be 2,239.6 hours.

On June 4, 1994, the pilot was unsuccessful in his attempt to pass a practical examination for his private pilot certification. On July 1, 1994, he completed a successful reexamination, and was issued his private pilot certification.

On February 25, 1995, the pilot was unsuccessful in his attempt to pass a practical examination for his instrument-airplane rating. On March 1, 1995, he completed a successful reexamination, and was issued his instrument-airplane rating.

The pilot attended formalized turbine-powered Bonanza training in the summer of 1996 at Flight Safety International. According to his flight instructor, the pilot related to him that en route to the training site, the pilot encountered a thunderstorm. This, in turn, resulted in hail damage to the airplane, and caused the airplane to lose about 6,000 feet of altitude. When the flight instructor asked what he did to get out of the situation, the pilot said that he tried to reverse course, but noticed he was in about a 60-degree bank, so he leveled the wings, put the landing gear down, reduced power, and "decided to plow through it."

The pilot also stated that upon arrival in the vicinity of the training site, he landed at the wrong airport, and ran off the runway and into the grass. He said he thought he was landing on Runway 36 at that airport, but landed on Runway 18 with a quartering tailwind of about 15 knots. The instructor confirmed the story about the landing with the airport's tower personnel. The instructor also confirmed the hail damage, which included some dings on the stainless steel wing leading edge de-ice system, and holes in the radome, some of which, the instructor could put his fingers through.

The pilot also told the instructor that one of the reasons he wanted to take the training is that he wanted to learn more about turbine engines. He had previously exceeded the engine temperature during a start, and had to have the hot section replaced.

According to an FAA accident/incident record, the pilot landed the accident airplane "with the landing gear in the up position" on August 10, 1996. The pilot had flown an instrument approach, then initiated a go-around and raised the landing gear. The pilot stated that on the second approach, he put the gear down, but the gear circuit breaker popped, failing to lower the gear. The pilot also stated that he did not notice the popped circuit breaker until the aircraft landed with the gear up. During a subsequent maintenance check, the landing gear operated "with no problems noted."

In a letter dated September 12, 1996, the FAA requested that the pilot take a competency re-examination, to "consist of Private/Instrument procedures with emphasis on rejected landings, missed approach procedures and emergency operations."

The pilot was unsuccessful in his attempts to pass reexaminations on November 12, 1996, November 20, 1996, and December 18, 1996.

In an FAA "Notice of Proposed Certificate Action" letter to the pilot, dated April 4, 1997, the following was stated in regards to the pilot's reexamination after the gear up landing:

"Subsequent to the...incident, you have attempted two (2) reexaminations. However, you have failed to successfully complete each of these two (2) reexaminations. By reason of the above, you lack the qualifications to be the holder of Private Pilot Certificate."

On September 11, 1997, the pilot successfully completed the reexamination.

According to an FAA Enforcement Investigative Report (EIR), on October 3, 1997, after making a night landing, the pilot taxied off the active runway, and realized he was on the grass, between the runway and the taxiway. The pilot then "turned the aircraft one hundred eighty degrees, and taxied back onto the active runway without a clearance or notifying the tower of his intentions." As a result, a Boeing 737 on short final had to go around.

The FAA requested reexamination of the pilot's competency, to be an "appropriate Private and Instrument practical test with emphasis on night flying in Turbo Prop Beech 36, ATC instructions and simulated emergency procedures."

On December 17, 1997, the pilot's reexamination attempt was unsatisfactory. The pilot was given a temporary certificate until January 20, 1998, and an extension which expired on February 20, 1998. In a March 10, 1998, letter to the pilot, an FAA Principal Operations Inspector noted that the pilot did not attempt to schedule a reexamination until called by another Inspector, on February 10, 1998. The letter also gave the pilot an additional 30 days from the date of the letter to complete the reexamination.

The pilot successfully completed his reexamination on April 2, 1998, and a temporary certificate was issued on that date.

Medical Information

On March 10, 1994, the manager of the FAA Aeromedical Certification Division, Civil Aeromedical Institute, wrote to the pilot that he was eligible for a third class medical certificate. However, it acknowledged the pilot's history of hypertension, and listed the requirements to maintain medical eligibility.

On an FAA Medical Certification System Medical Inquiry form which referred to the pilot, was written the following: "10/3/97 Totally lost - Failed several 609 rides. Need neuropsychological testing." It was dated November 24, 1997.

On November 25, 1997, a letter sent to the pilot from the manager of the Aeromedical Certification Division, stated that the FAA had received information which indicated a reasonable basis for a redetermination of the pilot's ability to meet medical standards prescribed in Part 67 of the Federal Aviation Regulations (FAR's). It also stated: "You may not be qualified to hold any class medical certificate."

The letter went on to request that the pilot "forward to this office current comprehensive neuropsychological testing."

The letter further stated:

"We would like to invite your attention to the provisions of FARs Section 61.53 and to caution you that in view of your possible disqualification, the exercise of the privileges of your medical certificate until such time as you have been found qualified by the FAA, may constitute a violation of this regulation."

On December 20, 1997, the pilot wrote to the Aeromedical Certification Division, and stated that he had talked with one of the FAA's staff physicians about "meeting the medical standards you desire." The pilot stated that the staff physician left it up to the pilot (who was a radiologist) as to what proof would be submitted. Additionally, the pilot offered to provide letters from his certified flight instructor and from his aeromedical examiner.

On January 8, 1998, the pilot was issued a third class medical certificate by a local aeromedical examiner. The pilot had mentioned on the application that he had voluntarily surrendered his certificate, "pending passing 609 checkride - Passed August 1997." However, on that application, he did not mention anything about the neuropsychological testing. The local medical examiner had typed on the application: "I called CAMI and was informed to issue certificate pending evaluation by FAA."

On January 26, 1998, a follow-up letter from the Aeromedical Certification Division to the pilot stated, in part: "...you are again requested to forward to this office current comprehensive neuropsychological testing." This letter repeated the caution about exercising the privileges of his medical certificate until qualified by the FAA.

On April 3, 1998, in another letter from the Aeromedical Certification Division to the pilot, it stated: "Based upon our review of the information submitted, we are unable to establish your eligibility to hold an airman medical certificate at this time."

It continued, "Please submit the results of your recent neuropsychological testing you indicated would be done in your February 1998 letter."

The letter ended with, "Please note that your medical certification has not been denied at this time; however, if no reply is received within 30 days from the date of this letter, we will have no alternative except to deny your application...."

On April 4, 1998, the pilot forwarded a copy of his test results to the Aeromedical Certification Division.

On an Aeromedical Certification Division staff comments sheet, dated May 12, 1998, the following was written: "Psychology report recently received...does not indicate pathology."

METEOROLOGICAL INFORMATION

According to Nav Canada records, at 0553, on the morning of the accident, the pilot contacted the London, Ontario, Flight Service Station (FSS) to file IFR flight plans from Hamilton to Buffalo at an altitude of 5,000 feet, and then on to Southern Pines at an altitude of 13,000 feet. In addition, he requested a weather briefing.

Current weather was not available for Hamilton, but for Toronto, it included a 2,500-foot broken layer, a temporary visibility of 4 miles in fog, and temporary ceilings of 700 feet broken. Forecast weather for Buffalo, until 0900, included scattered clouds at 1,000 feet, a broken layer at 2,500 feet, and temporary conditions of 5 miles visibility in light rain and fog, and a 1,000-foot broken layer. Forecast weather for Greensboro, North Carolina, from 1200 until 1600, included a scattered cloud layer at 3,000 feet, a broken layer at 7,000 feet, and an occasional broken layer at 3,000 feet.

Winds aloft were also provided, which included a temperature of minus 4 degrees Celsius at 12,000 feet, over Buffalo. At Raleigh-Durham, the temperature, until 1400, was forecast to be minus 1 degree at 12,000 feet.

Nav Canada records also showed that the pilot asked if there were any NOTAMs, and the specialist advised that he'd have to send away for the information, and that it would take 5 to 10 minutes. The pilot advised that he'd get them at Buffalo.

According to a Safety Board Meteorological Factual Report, in-flight advisories (AIRMETs ZULU and SIERRA) had been issued by the Aviation Weather Center (AWC) at Kansas City, Missouri, prior to the flight.

AIRMET ZULU, Update 1, issued May 12, 1998, at 0345, for "Ice and Freezing Level Valid Until May 12, 1000," included Pennsylvania and West Virginia, and called for occasional moderate rime/mixed icing in cloud in precipitation between 10,000 feet and flight level 180. Conditions continuing beyond 1000, improving northeast through 1600.

The freezing level was 8,000 to 10,000 feet along parts of the route of flight, 10,000 to 12,000 feet elsewhere in the northeast area.

AIRMET ZULU, Update 2, issued May 12, 1998, at 0945, for "Ice and Freezing Level Valid Until May 12, 1600," included Pennsylvania and West Virginia, and called for moderate to severe rime/mixed icing in cloud in precipitation between 18,000 feet and flight level 180. Conditions continuing beyond 1600, through 2200.

There was no evidence of thunderstorm activity or significant turbulence in the accident area at the time of the mishap.

The Meteorological Factual Report, provided 0800 radiosonde information from sites in Pittsburgh, Pennsylvania, and Sterling, Virginia, 92 nautical miles to the northwest, and 94 nautical miles to the east, respectively. Winds above Pittsburgh at that time, about 12,000 feet, were from 130 degrees true, approximately 11 knots, while winds above Sterling at that time, about 12,000 feet, were from 050 degrees true, approximately 9 knots.

Forecast winds, for Elkins, West Virginia, 0500 to 1300 on the day of the accident, at 12,000 feet, were from 040 degrees true, at 9 knots.

AIRCRAFT INFORMATION

The airplane had been modified, and possessed a supplemental type certificate for the installation of an Allison 250-B17F/2 turbine engine. The airplane was not pressurized, but did possess a supplemental oxygen system.

The airplane's Pilot Operating Handbook (POH) revealed that it had an engine icing protection system, which included engine inlet anti-ice, heated inlet fairing, de-ice propeller, continuous ignition, and cowl flap. The pitot tube was separately, electrically heated.

"A de-ice switch located on the pilot's lower subpanel controls electric inlet anti-ice, the heated inlet fairing, propeller de-ice, and continuous ignition."

The airplane also had a TKS "weeping fluid" deicing system installed on the airframe, including the windshield. However, according to the pilot's Bonanza flight instructor, most people flying the turbine-powered A36 would not normally carry TKS fluid onboard, unless they anticipated icing. The flight instructor further stated that having the fluid onboard would not have put the aircraft out of center of gravity limits, but since the reservoir was located in the right wing, it would have made the airplane fly "right wing down."

Under the heading "ICING CONDITIONS," the POH stated:

"Flight into icing conditions is prohibited. An inadvertent encounter with these conditions can best be handled using the checklist procedures in Section 3. The best procedure, of course, is to turn back or change altitude to escape icing conditions."

Additionally, in section 3, it stated:

"The engine ice protection system must be activated for flight or ground operation in visible moisture at an OAT of 5 degrees centigrade (41 degrees Fahrenheit) and below or while operating in falling or blowing snow, regardless of ambient temperature. This system must be operated in the above mentioned conditions even if there is no visible sign of airframe ice and/or snow accumulation."

The airplane's maintenance logbooks were not recovered. However, on a work invoice dated April 29, 1998, the total number of hours on the airplane was listed as 2,233.9.

According to the supplemental type certificate for the airframe, the center of gravity (CG) range for the airplane was +83.3 to +87.3 at 3,833 pounds, +81.0 to +87.7 at 3,650 pounds, and +74.0 to +87.7 at 3,100 pounds or less.

The flight instructor who gave the pilot formalized training in 1996 stated that with the turbine Bonanzas, the CG was shifted forward. He also stated that with himself and the pilot onboard with full fuel, they were well forward of the CG envelope. The instructor also stated:

"I don't recall the specifics, but we did a lot of work on weight and balance. I always do with people because they don't realize that there is a problem with forward CG in this airplane with two adult males and full fuel. His airplane was an exception, his airplane was well further forward on CG than any of the others I had flown...I probably have seen ten of them or so and his was well forward of the rest...."

The instructor also noted that the pilot had had the airplane re-weighed at Raytheon Aircraft Service. "It came out even worse than what the numbers on the papers said."

According to the POH, the airplane's maximum operating speed was 167 knots, indicated airspeed, and maximum maneuvering speed was 141 knots, indicated airspeed.

WRECKAGE AND IMPACT INFORMATION

The wreckage of the airplane was spread over a mile of wooded, hilly terrain at an elevation of about 3,000 feet. The wreckage was in numerous pieces, but four major sections were found north of a small river. The sections consisted of the empennage, with the vertical rudder and fuselage roofing attached; the left wing; the right wing; and the engine, still attached to the fuselage/cockpit area and flooring back to the baggage compartment. The last section was located at 39 degrees, 07.91 minutes north latitude, 79 degrees 27.09 degrees west longitude. Light materials and shaped pieces were found south of the river. The wreckage pattern was oriented along a north-south axis. A majority of the airplane was accounted for, except for a portion of the left aileron, the left stabilizer, and the left elevator.

The metal skin below the horizontal stabilizers contained vertical scratches, and a piece of the forward horizontal stabilizer spar, which remained attached to the vertical rudder, was twisted forward and the bottom aft. The matching outboard portion of right forward horizontal stabilizer spar, still attached to the right stabilizer, was rotated forward about 90 degrees. All push rods, control cables, and connecting points to the rudder and elevators were found in the wreckage. The cable ends were broom-strawed, and the metal pieces contained jagged surfaces with lipped edges. Both wings were separated from the fuselage, although all attaching bolts for the spars were found intact and attached in the wreckage. The forward main spar was found separated inboard of the right attaching bolts, and the top portion of the fractured spar had jagged surface appearance, with deformation in the bottom area.

The three-bladed propeller was still attached to the turbine engine, and exhibited no rotational scoring. The propeller spinner was crushed on one side, and two of the propeller blades were splayed outwards, along approximately the same alignment. The third propeller blade exhibited no damage. The lower right side of the engine sustained the majority of the impact damage. No indications of an in-flight failure of the engine were found. Both wing tip tanks were found approximately 500 yards further north of the engine, with a strong smell of fuel in their impact craters.

The landing gear handle was in the "up" position; however, the nose landing gear and left main landing gear were down. The right wing was upside down, and the gear was in the gear well; however, one of the gear doors was missing, and the other was ajar.

The de-ice switch was found in the "off" position, as was the pitot heat switch. However, both switches were of the "non-locking type," and their pre-impact positions could not be verified. Two other nearby switches, the battery switch and the heater switch, were also found in the "off" position.

There were no stains from the TKS system found, on either the airframe or the windshield.

RADAR INFORMATION

According to a recorded radar study by the Safety Board's Office of Research and Engineering, the accident airplane was proceeding on a southerly course, at 13,000 feet, with a ground speed of about 200 knots. Then, at 1057:00, it initiated a right turn, and the last transponder signal was received about 23 seconds later, at an altitude of 11,800 feet. Subsequent radar contact with the airplane was through primary returns only, which did not provide altitude readouts, and which became spread out over an approximately 16 square-mile area around the location of the wreckage.

The primary radar returns continued until 1100:31, when all radar return information ceased. According to the radar study, "The scattering of primary returns is consistent with the in-flight breakup of an aircraft. The signals occur as the radar beam is reflected off aircraft parts which may reach the ground much later than the primary wreckage."

The radar study also included smoothed ground speed calculations, with the last calculation based on the airplane's position at 1057:12. At that time, 3-point smoothing indicated an airplane ground speed of 242.37 knots, 5-point smoothing indicated a ground speed of 253.96 knots, and 7-point smoothing indicated a ground speed of 212.80 knots.

RESEARCH

Additional examination of the wreckage was conducted by the Safety Board Materials Laboratory. The wing and tail sections of the accident airplane were examined at a storage facility, and the elevator bell crank assembly was examined at the Laboratory.

According the Materials Laboratory factual report, both horizontal stabilizers had separated from airplane, but only the right stabilizer was recovered and was available for examination. "The portions of the front spar that remained attached to the empennage on both the right and left sides were twisted and bent, consistent with the leading edge of the stabilizer being twisted down and back." Additionally, paint transfer markings were found on both sides of the empennage, with directions consistent with a down and aft movement of the horizontal stabilizer.

The fracture surfaces from the front and rear spars of the horizontal stabilizer were also examined, and had an appearance consistent with overstress separation. There was no indication of pre-existing cracking.

The wings and fuselage were joined by a main spar, which ran underneath the cockpit. "The wing spar had separated near the right side of the fuselage, and the portion of the spar which ran through the fuselage remained attached to the left wing.... The forward side of the upper right wing spar was bent forward, while the top and aft sides separated with little bending deformation. The inner cap of the upper spar failed with almost no deformation. Both sections contained matte, textured fracture surfaces whose appearance and angle were consistent with a tensile overstress separation."

"The fracture at the bottom of the outer cap was scraped and rounded, consistent with a compressive overstress separation."

The mating section of the carry-through spar was attached to the left wing. "The sides of the outer cap on the upper spar were deformed outwards, and the upper spar was deformed slightly downwards. The fracture surfaces on the top of the outer cap on the upper spar were matte and angled along the shear plane, consistent with tensile overstress separation. The fracture surface morphology continued roughly halfway down the sides of the outer cap of the upper spar." Then, "the fracture surface switched angles and became rubbed, consistent with a compressive overstress separation. The inner cap of the upper spar was severely bent downwards...[and] also bent in on the sides, consistent with buckling damage."

"Both the outer and inner caps of the lower spar were bent upwards, consistent with buckling of the lower portion of the spar." Additionally, skin wrinkling was found on the aft side of the spar webbing, "consistent with a downward flexure of the wing tips."

An examination of four pieces of the bellcrank assembly with a binocular microscope revealed that "all fractures were typical of an overstress."

MEDICAL AND PATHOLOGICAL INFORMATION

Autopsies were conducted on the pilot and the passengers by the State of West Virginia, Office of the Chief Medical Examiner, South Charleston, West Virginia. Toxicological testing was performed on the pilot's remains by the FAA's Toxicology and Accident Research Laboratory, Oklahoma City, Oklahoma.

ADDITIONAL INFORMATION

On May 15, 1998, the wreckage was released to a representative from AIG Aviation, of American International Group, Inc.