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N502SB accident description

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Crash location Unknown
Nearest city Blain, PA
40.338416°N, 77.512488°W

Tail number N502SB
Accident date 03 Sep 1994
Aircraft type Cessna 310R
Additional details: None

NTSB description


On September 3, 1994, at 0110 eastern daylight time, a Cessna 310R, N502SB, owned and operated by SmithKline Beecham Bio Science Labs, and operating as Skibil 910 (SQB 910), struck the ground near Blain, Pennsylvania. The airplane was destroyed, and the pilot and passenger were fatally injured. Visual meteorological conditions prevailed, and the flight was operated on an Instrument Flight Rules (IFR) flight plan under 14 CFR Part 91.

The pilot was scheduled to fly seven flights with his first departure at 1830. On the sixth flight, he departed the Allegheny County Airport, West Mifflin, Pennsylvania, at 0031, en route to Pottstown, Pennsylvania, with 200 pounds of cargo onboard.

At 0106, control of flight 910 was transferred from the New York Air Route Traffic Control Center, to Harrisburg Approach Control, and it was cleared to descend from 9,000 feet to 7,000 feet. At 0114 the controller received a telephone call from Perry County Dispatch, regarding a possible airplane accident. The controller was unable to regain radio or radar contact with flight 910.

Witnesses in the area reported seeing the airplane in a descent, which one witness described as 45 degrees nose down. The airplane's rotating beacon was visible and several witnesses reported hearing a loud whine. Sparks were seen coming from the airplane. The outboard portion of the left wing struck a residence damaging the roof, window, and porch roof.

The accident impacted the ground during the hours of darkness about 40 degrees, 20 minutes North, and 77 degrees, 28 minutes West.


The pilot-in-command was the holder of a Commercial Pilot Certificate with airplane single and multi-engine land, and instrument airplane ratings. In addition, he held a 1st class FAA Airman Medical Certificate, with no limitations, issued on February 3, 1994.

According to the pilot's logbook, which was current through August 22, 1994, the pilot had a total time of 1897 hours, with 1486 hours in the Cessna 310. His pilot-in-command time was 1817 hours, with 1486 hours in the Cessna 310.

According to company records, he was upgraded to captain on April 22, 1994 and had flown 22 flights for a total of 139.6 hours as captain.

The passenger possessed a student pilot certificate.


The airplane was examined at the accident site on September 3, 1994, and later at Capital City Airport, Harrisburg, Pennsylvania.

The debris trail was 1509 feet long, on a heading of 355 degrees, starting with pieces of engine cowling doors, followed by elevator, horizontal stabilizer, rudder, and vertical stabilizer parts. The fuselage was 978 feet from the start, and both engines and propellers were 531 feet beyond the fuselage, and located within a 25 foot radius.

The left wing, outboard of the left engine, both engines, portions of both tip tanks, both horizontal stabilizers and elevators, and the upper portion of the vertical stabilizer and rudder were separated from the airplane.

The top of the fuselage was crushed level with the bottom of the windows. The landing gear was retracted. According to Cessna, measurement of the wing flap extension chain corresponded to 10 degrees of flap extension.

The left wing outboard of the left engine was 620 feet from the fuselage on a heading of 270 degrees. The inboard portion of the aileron was present and the push/pull tube between the aileron and aileron bellcrank was connected.

The outboard 15 inches of right aileron was separated from the wing and was recovered.

Both upper and lower engine cowlings were separated from the wings. The upper cowlings were bent upward and the lower cowlings bent down. The top portion of the firewall for both engines was bent rearward. The engine rails on the left engine were pulled out of the firewall and on the right engine had separated just in front of the firewall.

Flight control continuity was established with all control cables intact and attached, except for the left wing aileron cables which were frayed and irregular at the separation point.

Wrinkles were found on the top and bottom of both wings which angled from inboard aft to outboard forward, and inboard forward to outboard aft. Accompanying the wrinkles were several popped rivets. Similar wrinkles were found on the left and right elevators. Wrinkles, orientated inboard forward to outboard aft, were found on the right horizontal stabilizer. Damage to the left horizontal stabilizer precluded a determination of wrinkles.

The metal on the bottom of both tip tanks had a rippled appearance.

According to a Structures Factual Report from Mr. Paul Alexander, Aerospace Engineer, with the Safety Board:

...The left wing had separated just outboard of the engine (inboard of the battery box). Examination of the forward and aft spars disclosed evidence of tensile and compressive overstress on the upper and lower spar caps, respectively, which was consistent with primary failure of this portion of the wing in a negative direction....

...Examination of the forward and aft spars on the left horizontal stabilizer disclosed evidence of primary failure in the down (negative) and aft direction. The stabilizer skin was torn and ripped severely in several areas...The right horizontal stabilizer assembly was deformed, but less severely damaged than the left side. Its lower surface was deformed in a concave manner along its entire length.


An autopsy was conducted on the pilot by Dr. Malcolm Cowen, M.D. Forensic Pathologist, for Forensic Pathologist Associates, 1024 Highland Ave, Bethlehem, Pennsylvania, on September 4, 1994.

Toxicological testing was conducted by the FAA Civil Aeromedical Institute (CAMI), in Oklahoma City, Oklahoma, and SmithKline Beecham in Pottstown. Marihuana was found in the pilot's blood and urine at the following levels:

.002 ug/ml Tetrahydrocannabinol in blood .011 ug/ml Tetrahydrocannabinol Carboxylic Acid in blood .304 ug/ml Tetrahydrocannabinol Carboxylic Acid in urine

According to the toxicological factual report by Merritt M. Birky, Toxicologist, NTSB, Washington, DC, "...Evaluation of pilot performance on a flight simulator has been evaluated for up to 48 hours after marijuana use. This study showed decrements in pilot performance for up to 24 hours after marijuana use."


According to report, No. 95-59, by Mr. James Wildey, Metallurgist, NTSB, Washington, D.C., examination of the lower spar car and a piece of upper spar cap outboard of the wing fracture:

...No evidence of progressive cracking was noted anywhere...Smearing damage was found on the lower spar cap fracture....

Examination of the upper spar cap piece at the wing separation point revealed:

...The majority of the fracture contained crack arrest positions and was on a flat transverse plane, typical of fatigue cracking...The visual and SEM examinations revealed no defects that may have contributed to initiation of the fatigue cracking....


Drug testing was not required for 14 CFR Part 91 operations; however, the employment application signed by the pilot revealed the company had a drug testing program in place. There was no record that the employee was ever tested for drugs.

The pilot held certificates that meet FAA requirements for Pilot-In Command; however, the company flight operations manual called for captains to possess an Airline Transport Pilot Certificate. The SmithKline-Beecham Clinical Labs, flight department manager reported he possessed the authority to upgrade the pilot to captain even though he did not possess the company required certificates. No authority for this deviation was found in the manual.


The Safety Board recently examined 37 major air carrier accidents for which human performance issues were cited in the probable cause determination ("A Review of Flightcrew-Involved, Major Accidents of U.S. Carriers, 1978 through 1990." Safety Study NTSB/SS-94/01). One of the items studied was the time since awakening (TSA) of captains and first officers, which averaged 13.8 and 13.4 hours respectively for the high group, and 5.3 and 5.2 hours respectively for the low group. The study stated, "...Overall high TSA crews made an average of 40 percent more errors than low TSA crews...." According to the pilot's father, the pilot had been awake since 0600 (over 19 hours), and worked another job during the day.

Recorded radar data was supplied by the New York Air Route Traffic Control Center (ARTCC). The flight was identified by its assigned beacon code of 7477. The data was printed out graphically, and processed through the NASA designed program knows as MANAT.

The data revealed the airplane was on a easterly heading. With 9,000 feet as the assigned altitude, the altitude varied between 8,900 feet and 9,200 feet. The magnetic heading varied between 065 and 135 degrees.

During the descent from 9,000 feet to 7,000 feet, two level offs were observed, one at 8,400 feet and another at 8,100 feet, each lasting approximately 24 seconds. The descent then continued to 7600 feet. This was followed by a climb to 7800 feet, and a course change of approximately 30 degrees right, after which the airplane disappeared from radar.

The tabular printout from the MANAT program revealed the indicated airspeed increased during the final minute of recorded radar data.

According to the Cessna 310 Owner's manual, the never exceed speed was 227 KCAS, and maneuvering speed (maximum speed at which you can use abrupt control travel) was 150 KCAS. The maximum flight load was +3.8 flaps up or +2.0 flaps down, and -2.0

A survey of pilots who flew the accident airplane prior to the accident revealed no auto-pilot problems.

WRECKAGE RELEASE The aircraft wreckage was released to Mr. Kyle Moore of USAIG in Toledo, Ohio, on October 19, 1994.

(c) 2009-2018 Lee C. Baker / Crosswind Software, LLC. For informational purposes only.