On May 8, the first fatal crash of an Icon A5 light sport amphibious airplane occurred during a new-employee familiarization flight for a recently hired engineer. The NTSB took just one day shy of three months to release the final report on the accident. Most accident reports take a year or more to complete.
The precise path of the accident flight is known because the A5 is equipped with two sources of data; one is a flight data monitoring device that captures information from the flight data computer, and a second is part of the A5’s 100-hp Rotax 912IS Sport powerplant’s electronic engine control unit.
The data showed that the pilot and his passenger took off just before 9 a.m. in good VFR weather from Nut Tree Airport in Vacaville, Calif., in N184BA, A5 Serial Number 7, one of the company’s training airplanes with 182.7 hours flying time logged since it was manufactured last year. Icon conducts pilot training at Lake Berryessa, about a 15-minute flight from the company headquarters and assembly facility at Nut Tree. The company has another flight training facility in Tampa, Fla.
The recorded data showed that after departing Runway 2 at Nut Tree, the A5 climbed to a GPS altitude of 3,700 feet while flying north toward Lake Berryessa, then began descending as it neared the lake. After crossing the shore near Monticello Dam, the A5 descended to 450 feet GPS altitude (the lake’s elevation can range to more than 400 feet msl; its spillway is 440 feet msl).
Flying over the water, the A5 proceeded in a northerly direction, but then at 9:07:30 entered Little Portuguese Canyon. There is no outlet for this canyon, and the terrain surrounding the canyon rises steeply. According to the NTSB, “The areas of rising terrain that surrounded Little Portuguese Canyon varied between 780 and 1,420 feet msl. The accident site was located about 0.35 nautical mile (nm) from the tops of 1,200-foot-high ridges to the west, 0.36 nm from the 1,050-foot-high ridges to the east, and 1.34 nm from the 1,200-ft-high ridges to the north. In addition, Little Portuguese Canyon narrowed in width from about 700 feet at the opening to about 300 feet near the accident site and 240 feet near the farthest northern area of the canyon.”
To fly to the more open area of Lake Berryessa, before entering Little Portuguese Canyon it would have been necessary to make a 90-degree turn to the left followed by a 90-degree right turn to fly into the wide open lake recreation area.
According to the NTSB, when the A5 entered Little Portuguese Canyon, it was at 450 feet GPS altitude and 54 kias, as logged by the airplane’s recording devices. Twenty seconds later, power was added and the airplane climbed while turning slightly to the east, followed by a left turn to the west. The NTSB’s depiction of the recorded data shows the A5 flying toward the right side of Little Portuguese Canyon then turning sharply left before hitting terrain on the left side of the canyon (as viewed from the entry to the canyon).
After reaching a maximum GPS altitude of 506 feet, the A5 descended. “The airplane struck terrain at 09:08:06 at 470 feet GPS altitude and 66 knots indicated airspeed,” according to the NTSB.
The data shows that at the time of the accident the power was at maximum, landing gear was up and the flaps were not deployed.
Low-altitude Maneuvering
“A witness, who was in a boat on Lake Berryessa near the entrance to Little Portuguese Canyon, reported seeing the airplane flying about 30 to 50 feet above the lake at what appeared to be between 30 to 40 mph,” the NTSB wrote in its report. “The witness stated that the engine was running smoothly and that the airplane was level. The airplane passed by his position flying in a northerly direction and entered Little Portuguese Canyon. The witness reported hearing the engine ‘rev up and accelerate hard’ as the airplane approached the right side of the canyon ‘in what appeared to be an effort to climb out of’ the canyon. Subsequently, the airplane climbed to about 100 feet above ground level and then entered a left turn as it began to quickly descend. The witness stated that it appeared that the pilot attempted to make a ‘U-turn in the air’ just before the airplane flew beyond his field of view. The witness stated that he heard the sound of impact shortly after losing sight of the airplane.”
The NTSB found “no evidence of any preexisting mechanical malfunctions that would have precluded normal operation [of the A5].”
In its final report, the NTSB wrote, “It is likely that the pilot mistakenly thought the canyon that he entered was a different canyon that led to the larger, open portion of the lake. Additionally, it is likely that, once the pilot realized there was no exit from the canyon, he attempted to perform a 180-degree left turn to exit in the direction from which he entered. Based upon performance information outlined in the Pilot's Operating Handbook for the accident airplane, the airplane's altitude above the water’s surface and its indicated airspeed, and the ridge line elevations in the area adjacent to the accident site, the airplane would have not been able to climb out of the rising terrain that surrounded the area, which led to his failure to maintain clearance from terrain.”
The probable cause of the accident was: “The pilot's failure to maintain clearance from terrain while maneuvering at a low altitude. Contributing to the accident was the pilot's mistaken entry into a canyon surrounded by steep rising terrain while at a low altitude for reasons that could not be determined.”
Although the NTSB doesn’t release identities of those involved in accidents, Icon Aircraft founder and CEO Kirk Hawkins issued a statement following the release of the final report (the pilot and passenger names had been released shortly after the accident). At the controls of the A5 was Jon Karkow, lead engineer on the A5 program and well known in the aerospace industry for his 21 years working at Scaled Composites. The passenger was Cagri Sever, who had recently been hired by Icon.
“I want to thank the NTSB for its professionalism and thoroughness in this process; this is an important step in reaching closure for the families of Jon and Cagri as well as the Icon team after such a traumatic loss. Jon and Cagri were both extraordinary individuals and are missed tremendously. Cagri had recently joined Icon as a star engineering leader from Ford Motor Company. Jon was a legendary aircraft designer, test pilot and unsung hero in aviation. He was a founding member of the Icon team, the lead aero engineer on the A5 and a core part of Icon’s DNA. The A5 reflects not only his genius, but it also represents his love for flying in its purest form. It was his final gift to aviation. The Icon family is committed to carrying the flag forward in Jon and Cagri’s honor.”