History of Flight
On December 20, 2011, at about 0145 central standard time, a Cessna 172R airplane, registration N987BT, impacted terrain while executing the Instrument Landing System (ILS) approach to runway 18 at Denton Municipal Airport (KDTO), Denton, Texas. The commercial pilot was fatally injured, and the certificated flight instructor (CFI) and a student pilot observer/passenger were seriously injured. The airplane was operated by US Aviation Group, LLC as a personal flight under 14 CFR. Instrument meteorological conditions prevailed, and the flight operated on an instrument flight rules flight plan. The flight originated from San Antonio International Airport (KSAT) at 2323, destined for KDTO.
A review of pilot-ATC transmissions indicated that at 0057, ATC informed the pilots that KDTO weather reported 1/2 mile visibility and an indefinite ceiling of 100 feet. The pilots requested an approach to Fort Worth Alliance Airport (KAFW), where weather was 3 miles visibility with few clouds at 100 feet. At 0128, the pilots reported obtaining current KDTO weather and requested the ILS, as visibility was 1/2 mile with a 200-foot ceiling.
According to the observer, the flight was uneventful until the airplane began the ILS approach. The airplane entered a fog bank, and the observer saw airport lighting to the left before the airplane turned left and impacted terrain. The observer reported that the commercial pilot called out an altitude (possibly decision height), and the instructor stated, 'Descend a little more.' The crew realized they were not aligned with runway 18 and, instead of executing the published missed approach, attempted a circle-to-land on runway 36. After climbing during the circling maneuver, they judged insufficient runway for landing and initiated a missed approach. The airplane departed north, turned south, and then impacted terrain. The CFI sustained head injuries and did not recall the accident.
The purpose of the flight was to build flight time for the commercial pilot. Flight school policy required the CFI to be on board.
Personnel Information
The commercial pilot, age 30, held a commercial pilot certificate with airplane multi-engine land and instrument airplane ratings, as well as a private pilot certificate for airplane single-engine land. His logbook was not available for review, and his complete flight history is unknown. A first-class medical certificate without restrictions was issued on January 28, 2011. Sleep and awake times could not be determined.
The CFI, age 22, held an instructor certificate with airplane single-engine land and instrument airplane ratings, along with a commercial pilot certificate with airplane single-engine land, multi-engine land, and instrument ratings. His logbook was also unavailable. A first-class medical certificate without restrictions was issued on July 13, 2011. Sleep and awake times could not be determined.
Aircraft Information
The airplane was a single-engine, high-wing, fixed-gear Cessna 172R, serial number 17280452, manufactured in 1998. It was powered by a 180-horsepower Lycoming IO-360-L2A engine with a McCauley two-bladed fixed-pitch metal propeller. The last inspection was an annual inspection on January 20, 2011, at 7,904 airframe hours. Total airframe time at the accident was 8,833.9 hours.
Meteorological Information
At 0125, an automated weather observation at KDTO reported wind from 150 degrees at 7 knots, 1/2 mile visibility with fog, 200-foot vertical visibility, temperature 10°C, dew point 10°C, and barometric pressure 29.85 inHg. At 0153, visibility was 3/4 mile with mist, wind from 170 degrees at 7 knots, vertical visibility 200 feet, temperature 11°C, dew point 11°C, and pressure 29.85 inHg.
An NTSB meteorologist noted potential for clouds between the surface and 1,300 feet without icing, and potential for low-level wind shear between the surface and 2,000 feet. Infrared imagery detected low clouds and stratus over the accident area, with cloud tops estimated at 1,500 feet.
Navigation and Airport Information
The ILS 18 approach minima required a 200-foot ceiling and 1/2 mile visibility, with a decision height of 839 feet MSL. Circling minima for the airplane's category required a 600-foot ceiling and 1-mile visibility, with a circling altitude of 1,160 feet MSL. The inbound course was 177 degrees.
Denton Municipal Airport has a single runway 36/18, 7,002 feet long and 150 feet wide, with an asphalt surface. The control tower operates daily from 0600 to 2200.
Wreckage and Impact Information
The accident site was approximately 700 yards northwest of runway 18. Tree damage and impact marks were consistent with the airplane in a left turn. Both wings were torn and broken, with the left wing nearly separated from the fuselage. The left wing outboard of the flap separated. Both propeller blades showed leading edge polishing and gouging; one blade was bent rearward about 90 degrees near mid-span. Cockpit instruments were impact-damaged. The vertical speed indicator indicated an 1,800 fpm descent. The altimeter was set to 29.82 inHg. The course deviation indicator was set to about 177 degrees inbound. Flaps were set to 10 degrees. Engine continuity and thumb compression were verified; both magnetos produced sparks. No preimpact anomalies were found that would have prevented normal operation.
Medical and Pathological Information
An autopsy of the commercial pilot by the Tarrant County Medical Examiner determined the cause of death as blunt force injuries. Forensic toxicology by the FAA was negative for carbon monoxide, cyanide, ethanol, or drugs.
Search and Rescue
The airplane's instrument flight plan was not closed out. The Dallas/Fort Worth TRACON D10 supervisor coordinated with the Denton Police Department (DPD) to search for the airplane. At about 0300, a survivor who had extricated himself was found and reported a second survivor trapped. DPD requested assistance from sheriff, state police, and fire department. An Alert Notice (ALNOT) was issued at 0308. The Air Force Rescue Coordination Center (AFRCC) initiated search procedures but was incorrectly advised by Fort Worth Center that search was no longer needed; AFRCC terminated activities.
A Fort Worth Police helicopter arrived at about 0410 and searched 1.5 miles north of the airport based on initial coordinates. At 0433, D10 provided a revised location southwest of the original. At about 0545, a sheriff's deputy used a smartphone to 'ping' a cellular telephone of the trapped survivor, obtaining latitude/longitude coordinates. The helicopter relocated and found the airplane at 0548, with ground assistance arriving at 0550. The pilot was deceased; the remaining survivor was trapped further details are in DPD dispatch logs.
Radar Data
D10 used ASR-9 radar sites at DFW (east and west), Azle, and Sachse. The controller used the DFW-E site during the approach. Post-accident review showed that the DFW-W site detected additional targets, including four that tracked toward the crash site. The last DFW-W target was 259 yards from the crash site. None of the DFW-W data was provided to search teams.