Primary finding
Probable cause
The inadequate visual lookout and failure to see and avoid by the pilots of both airplanes while maneuvering to land, which resulted in a midair collision. Contributing to the accident was the lack of standardized, unequivocal procedures concerning common traffic advisory frequencies used in the area.
Investigator assessment
Analysis narrative
Aircraft 2 Two float-equipped, high-wing airplanes, a Cessna 206 and a Cessna 180, collided in midair in day visual meteorological conditions near a remote lake, which was the destination for both airplanes. The Cessna 206 pilot stated that he was maneuvering for landing after completing a right 270-degree turn, which positioned the airplane for a left downwind approach for landing to the northeast. The Cessna 180 was flying northbound and presumably also on a left downwind approach for landing to the northeast. The airplanes were about 900 feet above ground level when the collision occurred. The pilot of the Cessna 206 said he saw the Cessna 180 approaching from the right, and he made an immediate climbing left turn just before the collision. The Cessna 180 descended vertically to the ground. The Cessna 206 continued to fly and landed safely with the outboard portion of the Cessna 180’s left wing entangled in its floats. Neither pilot was in communication with any air traffic control facility. The airplanes were operating in uncontrolled airspace. The Cessna 206 pilot reported that he was monitoring 122.8 MHz, the common traffic advisory frequency (CTAF) for the area. A pilot-rated relative of the Cessna 180 pilot said the pilot monitored 122.9 MHz on previous flights, which was the MULTICOM frequency used for off-airport operations. A review of Federal Aviation Administration-approved CTAF radio frequencies used in the area revealed equivocal language regarding which CTAF radio frequency should be used. Additionally, due to a high concentration of aerodromes in the area, many of the frequency boundaries overlap. Given the reports of the radio frequencies that were monitored by both pilots, it is likely that, had both pilots been announcing their intentions on the same frequency, both pilots would have had increased awareness of the presence of the other airplane. --- Aircraft 1 Two float-equipped, high-wing airplanes, a Cessna 206 and a Cessna 180, collided in midair in day visual meteorological conditions near a remote lake, which was the destination for both airplanes. The Cessna 206 pilot stated that he was maneuvering for landing after completing a right 270-degree turn, which positioned the airplane for a left downwind approach for landing to the northeast. The Cessna 180 was flying northbound and presumably also on a left downwind approach for landing to the northeast. The airplanes were about 900 feet above ground level when the collision occurred. The pilot of the Cessna 206 said he saw the Cessna 180 approaching from the right, and he made an immediate climbing left turn just before the collision. The Cessna 180 descended vertically to the ground. The Cessna 206 continued to fly and landed safely with the outboard portion of the Cessna 180’s left wing entangled in its floats. Neither pilot was in communication with any air traffic control facility. The airplanes were operating in uncontrolled airspace. The Cessna 206 pilot reported that he was monitoring 122.8 MHz, the common traffic advisory frequency (CTAF) for the area. A pilot-rated relative of the Cessna 180 pilot said the pilot monitored 122.9 MHz on previous flights, which was the MULTICOM frequency used for off-airport operations. A review of FAA-approved CTAF radio frequencies used in the area revealed equivocal language regarding which CTAF radio frequency should be used. Additionally, due to a high concentration of aerodromes in the area, many of the frequency boundaries overlap. Given the reports of the radio frequencies that were monitored by both pilots, it is likely that, had both pilots been announcing their intentions on the same frequency, both pilots would have had increased awareness of the presence of the other airplane.
Source record
Factual narrative
HISTORY OF FLIGHT On July 30, 2011, about 1415 Alaska daylight time, a float-equipped Cessna U206G (206) airplane, N756MP, and a float-equipped Cessna 180B (180) airplane, N5214E, collided midair near Amber Lake, about 16 miles southwest of Talkeetna, Alaska. Each airplane was operated as a visual flight rules (VFR) personal flight under 14 Code of Federal Regulations (CFR) Part 91 in visual meteorological conditions when the accident occurred. The sole occupant of the Cessna 206, a certificated airline transport pilot, was not injured. The private pilot and three passengers of the Cessna 180 received fatal injuries. The Cessna 206 departed from Sister Lake about 1400, en route to Amber Lake. The Cessna 180 departed from Lake Hood Seaplane Base about 1330, en route to Amber Lake. The Cessna 206 sustained minor damage to its left float and float spreader. The Cessna 180, which entered an uncontrolled descent following the collision, was destroyed by the ground impact and the postcrash fire. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on July 31, the pilot of the Cessna 206 said that while on approach to Amber Lake he did not see the Cessna 180 coming from his right until the last seconds prior to the impact. He said he pulled his airplane up and left to avoid the collision. In a written statement to the NTSB dated August 8, the Cessna 206 pilot reported he departed Sister Lake to the north with a right 270 degree turn due to the terrain around the lake. His destination was Amber Lake less than a mile away to the southwest. The lake elevation was approximately 450 feet above mean sea level (msl), and the weather was VFR. He flew over his cabin, which put him on a left downwind for Amber Lake on the north side. His altitude was approximately 900 to 1300 feet msl, and he had his landing and taxi lights along with strobes and beacon on. His airplane’s radio was tuned to 122.8 MHz for traffic advisories, and he did not hear the Cessna 180 pilot on that frequency. He crossed the northeast end of the lake, scanned for traffic left and right, and checked the water for conditions. He was in a very slight right bank. As he rolled out of the bank, he looked to the right because that wing had been slightly down. The other aircraft came into view on his right at the same altitude. He reacted by pulling nose hard up and rolling left. The two airplanes collided. After the collision, he called on 122.8 MHz for help in the area and called Talkeetna radio on 123.6 and 121.5 MHz, gave the location of the accident, and asked for assistance. He circled the area to assess the damage to his airplane. His airplane had a strong vibration, and it took a lot of right rudder to fly straight and a lot of elevator to hold the nose level. It also took increased power to maintain altitude. After assessing the damage and options, he decided to head for Anchorage where crash fire rescue was available. As he approached Anchorage, another aircraft flew alongside to assess the damage further. He landed the airplane on a paved runway at the Ted Stevens Anchorage International Airport, Anchorage, without further difficulty and damage. During an on-scene interview with the NTSB IIC on July 30, the wife of the Cessna 206 pilot said she had walked outside of their cabin to watch her husband take off. While waiting for him to depart, she saw a high-wing airplane on floats to the north of her position transit the area in an east-northeast direction. After her husband departed, she watched him heading in a northerly direction, at the same time, she saw a high-winged, float-equipped airplane crossing to the north of her from the right/east. She thought it was the same airplane that she had seen previously headed in the opposite direction. As she watched, the airplanes appeared to be converging. She saw her husband’s Cessna 206 pitch up and roll left, and the two airplanes collided. She said the airplanes seemed suspended together for a few seconds, and she saw a flash and smoke as the unknown airplane plummeted toward the ground trailing smoke. PERSONNEL INFORMATION Cessna 206 pilot: At the time of the accident the pilot of the Cessna 206 was employed by a commercial air carrier as a Boeing 737 captain. The pilot, age 56, held an airline transport pilot certificate with ratings for airplane single-engine land, airplane multi-engine land, airplane single-engine sea, and airplane multi-engine sea. His most recent first-class medical certificate was issued on February 18, 2011, and contained the limitation that he must possess glasses. According to records provided by the pilot, he had logged about 19,100 hours of flight experience at the time of the accident. He also passed a currency check ride (biennial equivalent) on July 9, 2011. Cessna 180 pilot: The pilot of the Cessna 180, age 41, held a private pilot certificate with a rating for airplane single-engine land and airplane single-engine sea. He was issued a third-class airman medical certificate with limitations to wear corrective lenses on July 30, 2007. No personal flight records were located for the pilot, and the aeronautical experience listed on page 3 of this report was obtained from a review of the airman’s FAA records on file in the Airman and Medical Records Center in Oklahoma City. On the pilot’s last application for a medical certificate, dated July 30, 2007, he indicated that his total aeronautical experience consisted of about 220 hours, of which 50 were accrued in the previous 6 months. AIRCRAFT INFORMATION Cessna 206: The airplane was a Cessna 206, manufactured in 1977 and equipped with a Continental Motors IO-520 series engine. At the time of its last annual inspection, completed on June 21, 2011, the airplane had 2,530 hours in service. The colors of the airplane included a primary base color of white with red accent lines. The airplane was equipped with AEROFLASH wingtip and tail strobe lights, which were operating at the time of the collision. Cessna 180: The airplane was a Cessna 180 manufactured in 1959, and equipped with a Continental Motors O-470 series engine. No airplane and engine log books were discovered for examination. The colors of the airplane included a primary base color of white with burgundy and grey accent lines. According to a relative, the Cessna 180 was equipped with RMB tail and wingtip strobe lights. He said it was the habit of the pilot to fly with the strobe lights on at all times. METEOROLOGICAL INFORMATION The closest official weather observation station is Talkeetna, Alaska, about 16 miles northeast of the accident site. At 1353, an aviation routine weather report (METAR) was reporting, in part: Wind 210 degrees (true) at 5 knots; visibility 10 statute miles; sky condition, few at 3,500 feet; temperature 66 degrees F; dew point 50 degrees F; altimeter 29.77 inHg. COMMUNICATIONS No air traffic control services were requested by either airplane. An FAA publication dated May 14, 2008, titled, “Your Role in Collision Avoidance,” suggests that pilots make frequent position reports along their route and, at uncontrolled airports, broadcast their positions and intentions on common traffic advisory frequencies (CTAF). Additionally, in an FAA article titled, “Recommended Traffic Advisory Practices,” pilots of inbound traffic should monitor and communicate as appropriate on the designated CTAF from 10 miles to landing. Pilots of departing aircraft should monitor/communicate on the appropriate frequency from start-up, during taxi, and until 10 miles from the airport unless the CFRs or local procedures require otherwise. According to the Airman’s Information Manual (AIM), the CTAF frequency for a particular airport is contained in the A/FD, Alaska Supplement, Alaska Terminal Publication, Instrument Approach Procedure Charts,