Tallahassee, FL, USA
N5194X
CESSNA 172S
The airplane departed and climbed straight ahead to an altitude of about 600 feet before it began a left turn to the crosswind leg of the traffic pattern. It continued on a flight path toward hundreds of square miles of unlit, national forest land with the moon just above the horizon and behind the airplane. The airplane reached an altitude of about 1,000 feet as it turned from the crosswind leg to the downwind leg, and then descended in a continuous left arc toward the airport. The air traffic tower controller perceived the descent immediately and transmitted the airplane's registration number over the radio. One of the pilots responded by restating the number in business-like tone and there were no further communications from either pilot. Examination of the trees and airplane damage along the wreckage path was consistent with a shallow, wings-level, high-speed descent that suggested either one or both pilots nearly recovered control of the airplane during the last several seconds of descent to ground contact. A postaccident examination of the airframe and engine revealed no mechanical malfunctions or failures that would have precluded normal operation. Federal Aviation Administration guidance indicates that spatial disorientation can occur when there is no natural horizon or surface reference, such as a night flight in sparsely populated areas similar to that of the accident conditions.
HISTORY OF FLIGHT On November 4, 2009, about 1920 eastern standard time, a Cessna 172S, N5194X, operated by Eagle Aircraft, was destroyed after collision with wooded terrain and a post crash fire following a rapid descent after takeoff from Tallahassee Regional Airport (TLH), Tallahassee, Florida. The certificated flight instructor and the certificated private pilot were fatally injured. Night visual meteorological conditions prevailed for the local instructional flight that originated at TLH, about 1915. No flight plan was filed for the flight, which was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. A review of radar and voice communication data from the Federal Aviation Administration (FAA) revealed that the airplane requested and was cleared for "left traffic" pattern work at TLH. The airplane departed runway 36 at TLH, and climbed straight ahead to an altitude of about 600 feet mean sea level (msl) before it began a left turn to the crosswind leg of the pattern. The airplane reached an altitude of 1,000 feet as it turned from the crosswind leg to the downwind leg. During a span of approximately 10 seconds, the last three radar targets showed the airplane at 1,000 feet, 800 feet, and 400 feet respectively, in a left arc that oriented towards the airport. When it began its descent, the airplane was at 1,000 feet, three-fourths of a mile from the runway, and one-half mile from the perimeter fence. The tower controller reported that he was tracking the airplane visually, and noticed that the landing light and position lights were illuminated. He perceived the descent immediately, and voice communications revealed that at 19:16:39, he transmitted the airplane's registration number over the radio. At 19:16:41, the airplane responded with, "N5194X" in a clipped, business-like manner. There were no further communications from the airplane. Soon after, the controller sighted a "fireball" in the woods just west of the airport and alerted the airport fire department. PERSONNEL INFORMATION A review of FAA airman records revealed that the flight instructor held a commercial pilot certificate with a rating for airplane single-engine land, multiengine land, and instrument airplane. He held a flight instructor certificate with a rating for airplane single engine. His most recent FAA third class medical certificate was issued in March 2008. A pilot's logbook that belonged to the flight instructor was recovered at the site. The logbook entries began in June 2006, and predominantly reflected flights in Cessna model 152, 172, and 182 airplanes. The instructor logged 1,202 total hours of flight experience. He logged 40 hours of flight experience in the 90 days prior to the accident, and 20 hours of flight experience in the 30 days prior to the accident. He logged 133 total hours of flight experience at night. The instructor's total flight experience in Cessna 172 airplanes could not be established. The pilot held a private pilot certificate with ratings for airplane single engine land and instrument airplane. His most recent FAA second class medical certificate was issued in June 2008, and he reported 600 total hours of flight experience at that time. The pilot's logbook was not recovered; therefore his total flight experience could not be determined. A review of aircraft rental records revealed that between the time of the pilot's most recent FAA medical examination and the day of the accident, the pilot had accrued 48.2 hours of flight experience, all of which was in the Cessna 172. The pilot's night flying experience could neither be determined nor estimated. AIRCRAFT INFORMATION According to FAA and maintenance records, the airplane was manufactured in 2002, and its most recent 100-hour inspection was completed November 4, 2009, at 2,956.6 total aircraft hours. Interpolation of the Glide Distance Chart in the Cessna 172S Information Manual revealed that at best glide airspeed, from 1,000 feet above the airport, the airplane could travel 1.75 miles in calm winds. Examination of radar data revealed that at its farthest point from the departure runway, the accident airplane was at 1,000 feet altitude, .75 miles from the airport perimeter fence, and .92 miles from the departure runway. METEOROLOGICAL INFORMATION At 1944, the weather reported at TLH included clear skies and calm winds. The visibility was 10 miles. The temperature was 15 degrees Celsius (C) and the dew point was 12 degrees C. The altimeter setting was 30.23 inches of mercury. At 2053, the weather reported at TLH included few clouds at 500 feet, and the visibility was 8 miles in smoke. The smoke was attributed to a "controlled burn" being conducted in the Apalachicola National Forest, which bordered the airport, and extended hundreds of square miles west and south of the airport. At the time of the accident, the moon was 0.9 degrees above the horizon, at an azimuth of 061 degrees and was 94 percent illuminated, which placed the moon behind the accident airplane as it turned from the upwind leg to the crosswind leg of the traffic pattern. AERODROME INFORMATION TLH was located about 4 miles southwest of downtown Tallahassee, Florida. The official airport elevation was 81 feet. The airport was tower-controlled, and the tower was open and operating at the time of the accident. Runway 18/36 was 6,076 feet long and 150 feet wide and was located along the west side of the field. Runway 9/27 was 8,000 feet long and 150 feet wide and was located along the south side of the field. The airport was bordered to the west and south by the Apalachicola National Forest, which was hundreds of square miles of densely wooded, unlighted terrain, with little to no ambient light (street lights, structures, vehicle traffic, etc.). Among the Safety Board's findings during its investigation of the Federal Express Flight 1487 crash at TLH (NTSB/AAR-04/02), was that the approach over the Apalachicola National Forest produced conditions conducive to the "Black Hole" approach illusion. The report stated, "The approach to runway 9 at Tallahassee Regional Airport (which was flown over unlighted terrain and in night visual conditions) resulted in black hole conditions, which likely contributed to the flight crew's failure to properly perform the approach." WRECKAGE AND IMPACT INFORMATION The airplane was examined at the site and all major components were accounted for at the scene. The wreckage path was on flat, wooded terrain, oriented 110 degrees magnetic, and was about 600 feet in length. Trees along the wreckage path toward the main wreckage were broken off in small increments, at progressively lower heights above the ground, and several pieces of angularly cut wood were scattered about. The cockpit, cabin, and the inboard sections of both wings were consumed by fire. Examination of the cockpit revealed no discernible instruments or retrievable data. The outboard portions of both wings and the tail section were separated by impact. Control cable continuity was established from the flight control surfaces, to their respective cable breaks, and ultimately to the cockpit area. All cable, pulley, and bellcrank failures were consistent with overload. The engine was separated from the airframe and damaged by fire. The propeller was separated from the crankshaft, and the examination revealed fracture surfaces consistent with overload. The number 2 propeller blade displayed a slight aft bend. The number 1 blade displayed twisting along its entire length, and about 5.5 inches was separated at the tip. The blade tip was not recovered. The number 1 blade was sectioned below the fracture, and the section of blade was forwarded to the NTSB materials laboratory in Washington, DC. The fracture surface was examined on December 9, 2009, and examination revealed the fracture was consistent with "mechanical overstress." Paint transfers consistent with the color of the nose cowling were observed around the circumference of the propeller spacer. The fiberglass nose cowling exhibited deep scoring around the propeller opening. The engine was rotated by hand through the upper vacuum accessory drive and continuity was established through the accessory section to the valvetrain and powertrain. Compression was confirmed in all cylinders using the thumb method. The top four spark plugs were removed and the electrodes were intact and all were light tan and gray in color. Neither magneto could be tested due to fire damage. Both vacuum pumps were opened and each rotor was free, and all vanes were intact. On January 14, 2010, the wreckage was re-examined in Groveland, Florida by an NTSB investigator and a representative of Cessna Aircraft. The re-examination revealed no evidence of any pre-impact mechanical anomalies. MEDICAL AND PATHOLOGICAL INFORMATION The Office the Chief Medical Examiner, Tallahassee, Florida performed autopsies on both pilots. The autopsy reports indicated that both pilots died as a result of “multiple blunt-force trauma.” The FAA’s Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicological testing on specimens from the pilot and instructor. The tests were negative for carbon monoxide, cyanide, ethanol, and drugs. ADDITIONAL INFORMATION According to FAA Advisory Circular AC 60-4A, "Pilot's Spatial Disorientation," tests conducted with qualified instrument pilots indicated that it can take as long as 35 seconds to establish full control by instruments after a loss of visual reference of the earth's surface. AC 60-4A further states that surface references and the natural horizon may become obscured even though visibility may be above VFR minimums and that an inability to perceive the natural horizon or surface references is common during flights over water, at night, in sparsely populated areas, and in low-visibility conditions. A book titled, Night Flying, by Richard Haines and Courtney Flatau, provides some additional information concerning vertigo and disorientation. It states the following: "Vestibular disorientation refers to the general feeling that one's flight path isn't correct in some way. By calling this effect vestibular, it emphasizes the role played by the middle ear's balance organ. Flying an uncoordinated turn produces this effect as does excessive head turning during a turn in flight. Vestibular disorientation is often subtle in its onset, yet it is the most disabling and dangerous of all disorientation." In the textbook “Fundamentals of Aerospace Medicine, Fourth Edition” (Editors JR Davis, R Johnson, J Stepanek, and JA Fogarty, 2008), it is noted that "G-induced excessive movement of the pilot’s otolithic membranes causes the pilot to feel an extra amount of head and body tilt, which is interpreted as an underbank of the aircraft when the pilot looks up to the inside of the turn. Correcting for the illusion, the pilot overbanks the aircraft and it descends” (Parmet AJ, Killingham KK. Chapter 6: Spatial Orientation in Flight, page 179, figure 6-34). According to the 2010 Aeronautical Information Manual 8-1-5.b.2.(d): “Somatogravic illusion. A rapid acceleration during takeoff can create the illusion of being in a nose up attitude. The disoriented pilot will push the aircraft into a nose low, or dive attitude. A rapid deceleration by a quick reduction of the throttles can have the opposite effect, with the disoriented pilot pulling the aircraft into a nose up, or stall attitude.” In addition, the pilot, after initiating the turn, would have been susceptible to a G-excess illusion – if he were looking up and to the inside of the turn, as if looking for the airport, the increased g-loading in the turn may have given him the sense that the aircraft was beginning to roll out of the turn, and he may have increased roll to compensate. A common reference text in aerospace medicine notes that “G-induced excessive movement of the pilot’s otolithic membranes causes the pilot to feel an extra amount of head and body tilt, which is interpreted as an underbank of the aircraft when the pilot looks up to the inside of the turn. Correcting for the illusion, the pilot overbanks the aircraft and it descends.” According to AC 60-4A, "The Graveyard Spiral is … associated with a return to level flight following an intentional or unintentional prolonged bank turn. For example, a pilot who enters a banking turn to the left will initially have a sensation of a turn in the same direction. If the left turn continues (~20 seconds or more), the pilot will experience the sensation that the airplane is no longer turning to the left. At this point, if the pilot attempts to level the wings this action will produce a sensation that the airplane is turning and banking in the opposite direction (to the right). If the pilot believes the illusion of a right turn (which can be very compelling), he/she will reenter the original left turn in an attempt to counteract the sensation of a right turn. Unfortunately, while this is happening, the airplane is still turning to the left and losing altitude. Pulling the control yoke/stick and applying power while turning would not be a good idea–because it would only make the left turn tighter. If the pilot fails to recognize the illusion and does not level the wings, the airplane will continue turning left and losing altitude until it impacts the ground."
The pilots' spatial disorientation during flight in dark conditions, which resulted in an uncontrolled descent into terrain.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
