Pontiac, IL, USA
N503D
Air Tractor AT-503A
The airplane collided with the terrain following a loss of control while maneuvering during a training flight. The purpose of the flight was for one certified flight instructor (CFI) to give another CFI a checkout in a turboprop airplane. One witness described the airplane flying swath runs prior to making a wing over type maneuver and entering a spin. Several other witnesses describe the airplane being in a slight nose down spin prior to it impacting the ground. Inspection of the airplane failed to reveal any pre-existing failure/malfunction which would have resulted in the loss of control.
HISTORY OF FLIGHT On May 5, 2003, at 1414 central daylight time, an Air Tractor AT-503A, N503D, collided with the terrain following a loss of control while maneuvering during a training flight in Pontiac, Illinois. Both certified flight instructors (CFI) onboard the airplane were fatally injured. The airplane received substantial damage. The 14 CFR Part 91 training flight was operating in visual meteorological conditions without a flight plan. The flight originated from the Pontiac Municipal Airport (PNT), Pontiac, Illinois, approximately one hour prior to the accident. The purpose of the flight was for one CFI to give the other a checkout in a turboprop airplane. Witnesses described seeing the airplane descending to impact with the terrain. One witness stated the airplane was "traveling southbound at which time it turned around and proceeded north. The plane then repeated this movement twice. On the third trip north, the plane began its downward spiral." This witness stated the airplane did a "wing over" type maneuver prior to entering the spiral. When asked to demonstrate what the spiral looked like using a model airplane, the witness showed the airplane in a nose down spin. He stated he believed the airplane was spinning to the right. He stated he heard the engine noise before the airplane started to spin, but he did not hear it once the airplane was in the spin. The witness stated he saw a "light white smoke" coming from both wingtips as the airplane descended. (The fuel overflow vents are located near the wingtips.) This witness was located approximately one mile away from the accident site. Another witness reported she first saw the airplane at a low altitude in a nose low spiral/spin. This witness stated it sounded like the engine was sputtering. Another witness, who flew radio control airplanes, stated the airplane descended in a flat spin. He stated the engine was "racing" and he thought it was an airshow airplane because of the white smoke coming from the wingtips. This witness stated the airplane "nosed over" just prior to contacting the ground. The witness stated he heard less or possibly no engine noise when the airplane was at a higher altitude, and it took a long time, 45 seconds to a minute, for the airplane to descend. The witness described the airplane spinning clockwise or to the right. Another witness reported first noticing the airplane when it was at an altitude of 1,000 to 1,500 feet above the ground. He reported seeing the airplane in a slight nose down flat spin and did not recall any smoke coming from the airplane. PERSONNEL INFORMATION The CFI who was giving the checkout held an instructor certificate with single engine land, multi-engine land, and instrument airplane ratings. The CFI last had his certificate renewed on September 14, 2001. In addition, the CFI held an airline transport pilot (ATP) certificate which contained a multi-engine land airplane rating, along with commercial privileges for airplane single engine land and single engine sea, and private pilot privileges for rotorcraft helicopter. The CFI giving the checkout held a second-class Federal Aviation Administration (FAA) medical certificate dated October 19, 2002. His medical certificate contained the limitation "Holder shall possess glasses that correct for near vision." On his medical application, the pilot reported having a total of 7,852 hours of flight time of which 50 hours were flown in the last 6 months. He reported on the application for the medical certificate that he was not taking any medications. This CFI was seated in the rear seat of the airplane. The CFI who was receiving the checkout held an instructor certificate with an airplane single engine land rating. He also held a commercial pilot certificate with single engine land and instrument airplane ratings. Copies of a logbook indicate this pilot began flying aerial application flights in 1990. The last individual flight entries in the logbook are dated 1998. The logbook had a Biennial Flight Review entry dated January 27, 2003. There is an entry in the back of this CFI's logbook that states, "discussion on operations of PT-6-34 turbine engine, start procedures-flite operations, emergency airstarts and shutdown operations. Discussion of Airtractor 402, 503 operations including engine start, operations, electrical systems and malfunctions, airstart procedure, taxi, takeoff, landing operations and shut down. Total ground school 2.1 hrs." This entry is dated May 4, 2003, and was signed by the CFI who was giving the checkout. The CFI receiving the checkout held a second-class FAA medical certificate dated January 27, 2003. There were no limitations listed on his medical certificate. On his medical application, the pilot reported having a total of 3,000 hours of flight time of which 300 hours were flown in the last 6 months. This CFI was seated in the front seat of the airplane. AIRCRAFT INFORMATION The airplane was an Air Tractor AT-503A, s/n 503A-0067. The AT-503A is a tandem seat 2-occupant airplane used for agricultural applications. The airplane had an experimental airworthiness certificate. The aircraft operator stated the airplane was topped off with fuel on May 2, 2003, and it had flown 1.25 hours since that time. The chemical hopper was empty. The Aircraft Bluebook lists the maximum gross weight of the AT-503A as 9,700 pounds. The operator calculated the gross weight of the airplane at the time of the accident to be 6,124 pounds with a center of gravity (cg) of 27.43 inches. The aft cg limit is 28.0 inches. The engine was a 750 horsepower Pratt & Whitney PT-6A turbo propeller engine. METEOROLOGICAL INFORMATION A weather observation station located at PNT, approximately 4 miles northeast of the accident site, recorded the weather approximately 9 minutes prior to the accident as: Observation Time: 1405 cdt Wind: 260 degrees at 18 knots gusting to 26 knots Visibility: 10 statute miles Sky Condition: Scattered clouds at 500 feet Temperature: 23 degrees Celsius Dew Point: 13 degrees Celsius Pressure: 29.52 inches of mercury WRECKAGE AND IMPACT INFORMATION Inspectors from the FAA Flight Standards District Office in Springfield, Illinois, conducted the on scene portion of the investigation. The main wreckage was located in an open field at 1000 Deerfield Road, Pontiac, Illinois. The airplane came to rest upright on a magnetic heading of 240 degrees. Ground scoring showed little if any forward motion of the airplane as it impacted the ground. All of the wreckage was confined to the area immediately surrounding the airplane. All of the flight control surfaces were present and flight control continuity was established from the surfaces to the cockpit flight controls. The amount of fuel on board could not be verified as both fuel tanks were ruptured due to impact damage. The cockpit was intact with little damage other than minor crush damage and a small post impact electrical fire. Both main landing gear were crushed under the fuselage. Both main gear and the tail wheel were bent toward the right. The inspectors reported that the propeller blades exhibited chordwise scratching and approximately 6 inches of one blade had broken off. The separated portion of the blade was located near the main wreckage. Photographs show one propeller blade was partially buried in the ground, one was relatively straight, and the third blade was twisted. The inspectors reported that when viewed from the rear of the airplane, the tail and fuselage were bent to the left. Both wings were crushed, but they remained attached to the fuselage. The ailerons and spray booms were attached to the wings. The airplane was equipped with winglets and vortex generators. The winglets remained attached to the wings. Some of the vortex generators has separated from the wings and were found in the area of the main wreckage. The hopper was intact and empty. The horizontal stabilizer remained attached with the elevator partially separated. The vertical stabilizer was attached to the airframe. The rudder was separated from the vertical stabilizer and it was found 3 to 4 feet behind the main wreckage. MEDICAL AND PATHOLOGICAL INFORMATION Autopsy examinations on both pilots were performed at the McLean County Coroner's Office, Bloomington, Illinois, on May 6, 2003. A Forensic Toxicology Fatal Accident Report was prepared for each pilot by the FAA Civil Aeromedical Institute, Oklahoma City, Oklahoma. The toxicological results for the CFI giving the checkout were: No Carbon Monoxide Detected in Blood No Cyanide Detected in Blood No Ethanol Detected in Urine Metoprolol Detected in Blood Metoprolol Present in Urine Metoprolol is a prescription drug used to treat high blood pressure. It is also used to prevent angina and heart attacks. Side effects while taking Metoprolol are uncommon. The toxicological results for the CFI receiving the checkout were: No Carbon Monoxide Detected in Blood No Cyanide Detected in Blood No Ethanol Detected in Vitreous 0.032 (ug/ml, ug/g) Diphenhydramine Detected in Blood Diphenhydramine Present in Urine Diphenhydramine is an over-the-counter antihistamine used to treat sneezing, runny nose, itching, watery eyes, hives, rashes, and other symptoms of the common cold and allergies. The most common side effect of Diphenhydramine is drowsiness. ADDITIONAL INFORMATION The Federal Aviation Administration was a party to this investigation. The main wreckage was released to the registered aircraft owner on May 7, 2003.
The pilot's failure to maintain adequate airspeed which resulted in an inadvertent stall/spin. A factor associated with the accident was the low altitude maneuver.
Source: NTSB Aviation Accident Database
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