Primary finding
Probable cause
The inadequate visual lookout by the pilots of both airplanes, which resulted in a mid-air collision.
Investigator assessment
Analysis narrative
Radar track data depicted the accident airplanes on gradually converging flight paths prior to the accident. Immediately before the collision, the Cessna 172 appeared to be on a north-northeast course in level flight at 7,200 feet mean sea level (msl), and the Cessna 180 was in a gradual climb from 6,800 feet msl to 7,000 feet msl on a north course. Day visual meteorological conditions prevailed at the time of the accident, with reported visibilities at 60 miles. Neither pilot was receiving air traffic control advisories at the time of the collision. The radar track associated with the Cessna 180 indicated that after the collision the airplane entered a 270-degree right turn before proceeding to the west. The Cessna 172 continued northbound, as it entered a descent and impacted the ground. The pilot of the Cessna 180 airplane stated that she heard a loud bang during cruise flight and the airplane immediately pitched up and rolled into right bank. She subsequently determined that elevator control was limited. The pilot attempted to divert to a local airport, but was unable to land on a runway due to the impaired airplane control. She executed a forced landing to an open area adjacent to the airport. A witness reported that the right horizontal stabilizer of the Cessna 180 appeared to be bent down about 90 degrees at mid-span as the airplane approached for the forced landing. The outboard portion of the right horizontal stabilizer of the Cessna 180 airplane was structurally compromised, which resulted in a nearly complete loss of pitch control. The pilot of the Cessna 180 airplane retained marginal pitch control by varying engine power during the remainder of the flight. A postaccident examination did not reveal any pre-collision failures or malfunctions associated with either airplane. The examination determined that the left aileron/wing of the Cessna 172 likely contacted the right horizontal stabilizer of the Cessna 180 in flight. The outboard portion of the left wing on the Cessna 172 was structurally compromised, rendering the airplane uncontrollable. Regulations required that each person operating an aircraft maintain vigilance so as to "see and avoid other aircraft."
Source record
Factual narrative
Aircraft 2 HISTORY OF FLIGHT On March 23, 2012, about 1143 mountain daylight time, a Cessna 172S, N10468, and a Cessna 180, N9325C, were substantially damaged during a mid-air collision near Longmont, Colorado. The Cessna 172 impacted an embankment adjacent to a two-lane roadway, about 5 miles east of the Vance Brand Airport (LMO). The Cessna 180 impacted power lines and a chain link fence during a forced landing adjacent to LMO. The flight instructor and private pilot receiving instruction on-board the Cessna 172 were fatally injured. The pilot of the Cessna 180 sustained minor injuries. The Cessna 172 was registered to MountainAir Aviation Services LLC and operated by McAir Aviation LLC under the provisions of 14 Code of Federal Regulations Part 91 as an instructional flight. The Cessna 180 was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flights, which were both operated without flight plans. The Cessna 172 departed Rocky Mountain Metropolitan Airport (BJC) about 1130. The Cessna 180 departed Erie Municipal Airport (EIK) about 1136. At 1130, the Cessna 172 was issued a takeoff clearance by the BJC air traffic control tower. At 1132, an aircraft on a 1200 transponder beacon code [the standard code for visual flight rules (VFR) operations] was observed on Denver Terminal Radar Approach Control (TRACON) facility radar in the vicinity of BJC. Based on the subsequent course flown, this aircraft is presumed to be the Cessna 172 airplane. The radar track data indicated that the airplane initially proceeded on a northwest course from BJC, before turning to a north-northeast course. About 11 miles north of BJC, the airplane executed a left 360-degree turn and returned to a north-northeast course. The track data depicted the airplane converging with a second target about 0.5 miles south of the Cessna 172 accident site. At 1136, an aircraft on a 1200 (VFR) transponder beacon code was observed on Denver TRACON facility radar in the vicinity of EIK. Based on the subsequent course flown, this aircraft is presumed to be the Cessna 180 airplane. The radar data indicated that the airplane departed to the south and executed a right 180-degree turn to a northwest course. The airplane subsequently turned right to a north-northeast course. The radar track data depicted the flight paths slowly converging to a point about 0.5 miles south of the Cessna 172 accident site. The data indicated that the Cessna 172 was at 7,200 feet mean sea level (msl), while the Cessna 180 was in a slow climb from 6,800 feet to 7,000 feet msl. At 1142:28 (hhmm:ss), the airplanes were separated laterally by about 393 feet and vertically by about 200 feet. A loss of potentially two radar data points corresponding to the Cessna 180 was observed between 1142:29 and 1142:41. The loss of the data points is consistent with the close proximity to the second airplane at the time of the collision. At 1142:42, track data associated with the Cessna 180 indicated an altitude of 7,400 feet msl. The airplane subsequently descended to 7,000 feet msl and entered a right 270-degree turn to a west course. At 1143:37, the Cessna 180 was established on a west course at 6,200 feet msl. Track data associated with the Cessna 172 depicted the airplane continuing on a north course in the direction of the accident site. At 1142:37, the Cessna 172 was at 7,200 feet msl. The airplane subsequently entered a descent, passing 6,800 feet msl at 1142:42. The final radar data point was recorded at 1142:46, with an associated altitude of 6,300 feet msl. The accident site was located 0.14 miles north-northeast of the final radar data point. The Cessna 180 pilot stated that she was northbound at approximately 7,000 feet mean sea level, when she heard a loud bang. The airplane immediately pitched up about 50 degrees and rolled into a 45-degree right bank. She adjusted engine power to control airplane pitch and was able to maintain flight; although, only with a 200 foot-per-minute descent. She subsequently determined that aileron (roll) control and engine operation were normal, but there was limited elevator (pitch) control. The pilot attempted to divert to LMO; however, she ultimately executed a forced landing to a small open area adjacent to the airport in order to avoid trees short of the runway. She did not initially believe that she had been involved in a mid-air collision because she had not seen or heard another airplane; only the loud bang, which she thought was an elevator system failure. A witness located at the Longmont Airport reported that as the Cessna 180 approached it appeared that it couldn't turn to the left. As the airplane approached a line of trees, the engine increased power and the airplane nosed up. Engine power was then reduced and the airplane pitched down again. At this point, the airplane was not getting closer to the runway. The witness noted that the wings appeared to be intact and the engine seemed to be producing power. However, it appeared that the right horizontal stabilizer was bent down approximately 90 degrees at mid-span. PERSONNEL INFORMATION The Cessna 172 flight instructor held a commercial pilot certificate with single and multi-engine land airplane, and instrument airplane ratings. He held a flight instructor certificate with single-engine airplane and instrument airplane ratings, which had been renewed on April 29, 2011. He was issued a second class airman medical certificate with a limitation for corrective lenses on July 30, 2008. Records indicated that the flight instructor had accumulated about 796 hours total flight time, which included about 789 hours in single engine airplanes. Of the total flight time, about 743 hours were conducted as pilot-in-command and about 565 hours as flight instructor (dual given). The flight instructor's most recent flight review was completed on July 27, 2011. The Cessna 172 pilot receiving instruction held a private pilot certificate with a single-engine land airplane rating. He was issued a third class airman medical certificate with a limitation for corrective lenses on October 6, 2011. On the application for the medical certificate, the pilot reported a total flight time of 312 hours, with 4 hours within the previous 6 months. The Cessna 180 pilot held a commercial pilot certificate with single and multi-engine land airplane, and instrument airplane ratings. She held a flight instructor certificate with single and multi-engine airplane and instrument airplane ratings. She also had a current appointment as a Federal Aviation Administration (FAA) designated pilot examiner. She was issued a second class airman medical certificate with a limitation for corrective lenses on January 31, 2011. Records indicated that she had accumulated about 6,315 hours total flight time, which included about 6,250 hours in single-engine airplanes and about 825 hours in Cessna 180 model airplanes. The total flight time included about 4,656 hours as flight instructor (dual given). Her most recent flight review was completed on November 12, 2010. AIRCRAFT INFORMATION The Cessna 172S, serial number 172S9817, was a high-wing, single-engine airplane, with a fixed tricycle landing gear configuration. It was powered by a 180-horsepower Lycoming IO-360-L2A engine, serial number L-31875-51A. The airplane was issued an FAA airworthiness certificate on May 16, 2005. The most recent annual inspection was completed on February 2, 2012, at 1,955 hours total airframe time. The engine had also accumulated 1,955 hours total time in service. The most recent maintenance was conducted on March 22, 2012, at 2,017 hours airframe time, and consisted of replacement of the left strobe light bulb. There was no record of outstanding maintenance items related to the airplane. The Cessna 180, serial number 31723, was a high-wing, singl --- Aircraft 1 HISTORY OF FLIGHT On March 23, 2012, about 1143 mountain daylight time, a Cessna 172S, N10468, and a Cessna 180, N9325C, were substantially damaged during a mid-air collision near Longmont, Colorado. The Cessna 172 impacted an embankment adjacent to a two-lane roadway, about 5 miles east of the Vance Brand Airport (LMO). The Cessna 180 impacted power lines and a chain link fence during a forced landing adjacent to LMO. The flight instructor and private pilot receiving instruction on-board the Cessna 172 were fatally injured. The pilot of the Cessna 180 sustained minor injuries. The Cessna 172 was registered to MountainAir Aviation Services LLC and operated by McAir Aviation LLC under the provisions of 14 Code of Federal Regulations Part 91 as an instructional flight. The Cessna 180 was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flights, which were both operated without flight plans. The Cessna 172 departed Rocky Mountain Metropolitan Airport (BJC) about 1130. The Cessna 180 departed Erie Municipal Airport (EIK) about 1136. At 1130, the Cessna 172 was issued a takeoff clearance by the BJC air traffic control tower. At 1132, an aircraft on a 1200 transponder beacon code [the standard code for visual flight rules (VFR) operations] was observed on Denver Terminal Radar Approach Control (TRACON) facility radar in the vicinity of BJC. Based on the subsequent course flown, this aircraft is presumed to be the Cessna 172 airplane. The radar track data indicated that the airplane initially proceeded on a northwest course from BJC, before turning to a north-northeast course. About 11 miles north of BJC, the airplane executed a left 360-degree turn and returned to a north-northeast course. The track data depicted the airplane converging with a second target about 0.5 miles south of the Cessna 172 accident site. At 1136, an aircraft on a 1200 (VFR) transponder beacon code was observed on Denver TRACON facility radar in the vicinity of EIK. Based on the subsequent course flown, this aircraft is presumed to be the Cessna 180 airplane. The radar data indicated that the airplane departed to the south and executed a right 180-degree turn to a northwest course. The airplane subsequently turned right to a north-northeast course. The radar track data depicted the flight paths slowly converging to a point about 0.5 miles south of the Cessna 172 accident site. The data indicated that the Cessna 172 was at 7,200 feet mean sea level (msl), while the Cessna 180 was in a slow climb from 6,800 feet to 7,000 feet msl. At 1142:28 (hhmm:ss), the airplanes were separated laterally by about 393 feet and vertically by about 200 feet. A loss of potentially two radar data points corresponding to the Cessna 180 was observed between 1142:29 and 1142:41. The loss of the data points is consistent with the close proximity to the second airplane at the time of the collision. At 1142:42, track data associated with the Cessna 180 indicated an altitude of 7,400 feet msl. The airplane subsequently descended to 7,000 feet msl and entered a right 270-degree turn to a west course. At 1143:37, the Cessna 180 was established on a west course at 6,200 feet msl. Track data associated with the Cessna 172 depicted the airplane continuing on a north course in the direction of the accident site. At 1142:37, the Cessna 172 was at 7,200 feet msl. The airplane subsequently entered a descent, passing 6,800 feet msl at 1142:42. The final radar data point was recorded at 1142:46, with an associated altitude of 6,300 feet msl. The accident site was located 0.14 miles north-northeast of the final radar data point. The Cessna 180 pilot stated that she was northbound at approximately 7,000 feet mean sea level, when she heard a loud bang. The airplane immediately pitched up about 50 degrees and rolled into a 45-degree right bank. She adjusted engine power to control airplane pitch and was able to maintain flight; although, only with a 200 foot-per-minute descent. She subsequently determined that aileron (roll) control and engine operation were normal, but there was limited elevator (pitch) control. The pilot attempted to divert to LMO; however, she ultimately executed a forced landing to a small open area adjacent to the airport in order to avoid trees short of the runway. She did not initially believe that she had been involved in a mid-air collision because she had not seen or heard another airplane; only the loud bank, which she thought was an elevator system failure. A witness located at the Longmont Airport reported that as the Cessna 180 approached it appeared that it couldn't turn to the left. As the airplane approached a line of trees, the engine increased power and the airplane nosed up. Engine power was then reduced and the airplane pitched down again. At this point, the airplane was not getting closer to the runway. The witness noted that the wings appeared to be intact and the engine seemed to be producing power. However, it appeared that the right horizontal stabilizer was bent down approximately 90 degrees at mid-span. PERSONNEL INFORMATION The Cessna 172 flight instructor held a commercial pilot certificate with single and multi-engine land airplane, and instrument airplane ratings. He held a flight instructor certificate with single-engine airplane and instrument airplane ratings, which had been renewed on April 29, 2011. He was issued a second class airman medical certificate with a limitation for corrective lenses on July 30, 2008. Records indicated that the flight instructor had accumulated about 796 hours total flight time, which included about 789 hours in single engine airplanes. Of the total flight time, about 743 hours were conducted as pilot-in-command and about 565 hours as flight instructor (dual given). The flight instructor's most recent flight review was completed on July 27, 2011. The Cessna 172 pilot receiving instruction held a private pilot certificate with a single-engine land airplane rating. He was issued a third class airman medical certificate with a limitation for corrective lenses on October 6, 2011. On the application for the medical certificate, the pilot reported a total flight time of 312 hours, with 4 hours within the previous 6 months. The Cessna 180 pilot held a commercial pilot certificate with single and multi-engine land airplane, and instrument airplane ratings. She held a flight instructor certificate with single and multi-engine airplane and instrument airplane ratings. She also had a current appointment as a Federal Aviation Administration (FAA) designated pilot examiner. She was issued a second class airman medical certificate with a limitation for corrective lenses on January 31, 2011. Records indicated that she had accumulated about 6,315 hours total flight time, which included about 6,250 hours in single-engine airplanes and about 825 hours in Cessna 180 model airplanes. The total flight time included about 4,656 hours as flight instructor (dual given). Her most recent flight review was completed on November 12, 2010. AIRCRAFT INFORMATION The Cessna 172S, serial number 172S9817, was a high-wing, single-engine airplane, with a fixed tricycle landing gear configuration. It was powered by a 180-horsepower Lycoming IO-360-L2A engine, serial number L-31875-51A. The airplane was issued an FAA airworthiness certificate on May 16, 2005. The most recent annual inspection was completed on February 2, 2012, at 1,955 hours total airframe time. The engine had also accumulated 1,955 hours total time in service. The most recent maintenance was conducted on March 22, 2012, at 2,017 hours airframe time, and consisted of replacement of the left strobe light bulb. There was no record of outstanding maintenance items related to the airplane. The Cessna 180, serial number 31723, was a high-wing, singl