Ontario, OR, USA
N9862C
North American T28A
The pilot and one passenger were conducting a flight to test the landing gear. Following a low pass over the runway, the engine lost total power, and the pilot performed a forced landing to a field, during which he was fatally injured, and the passenger sustained serious injuries. Postaccident examination of the carburetor revealed that, when the throttle arm was placed near the idle position, the internal idle valve was closed, which restricted fuel from flowing through the carburetor at lower power settings and likely resulted in the loss of engine power. It is likely that the pilot reduced the engine power during the low pass to a setting that would have allowed for the idle valve to close completely, thereby restricting the fuel flow. No additional anomalies were noted with the engine or airframe. The airplane had not flown for about 8 years and had undergone maintenance for the previous 10 months before it first flew 6 days before the accident. One of the maintenance items performed included installation of a new carburetor. The mechanic who performed the annual inspection reported that he assisted in adjusting the idle setting on the carburetor. Whether any additional maintenance was performed on the carburetor before the accident flight could not be determined, and the engine logbook was not available for review.
HISTORY OF FLIGHTOn August 9, 2019, about 1620 mountain daylight time, a North American T28A airplane, N9862C, was substantially damaged when it was involved in an accident near Ontario, Oregon. The pilot was fatally injured, and the passenger sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. The owner of the airplane reported that it had last flown in 2011, and that he purchased the airplane from his father’s estate auction in 2013. The owner said that he started working with various mechanics in October 2018, to get the airplane airworthy. During this time, the carburetor was removed, the engine-driven fuel pump and right wing scavenge pump were rebuilt, and a new carburetor was purchased, along with new spark plugs. Before the airplane was flown, the airplane was fueled with 20 to 30 gallons of fuel and various engine runs and taxi tests were performed. At the completion of the tests, 80 gallons of fuel was added to the fuel tanks (40 per side). The first flight following the maintenance work took place on August 3, 2019, was about 1 hour in duration and was flown by the accident pilot and passenger. During this flight, the pilot did one pass over the runway, flew to a nearby airport, then returned and conducted three touch-and-go landings, followed by a full stop landing. Throughout the entire fight, the landing gear was securely pinned in the down position. The pilot-rated passenger, who was seated in the aft seat, reported that the purpose of the accident flight was to test the landing gear. During the preflight inspection, he and the pilot checked the fuel in both fuel tanks, and he recalled that he could touch the fuel with his fingers. Following a normal engine start, they let the engine warm up, and taxied for takeoff. The passenger said that after takeoff, they conducted a low pass, followed by a touch-and-go landing and another low pass. Shortly after the second low pass, the engine lost power and the pilot initiated a forced landing to an open dirt field ahead of the airplane. The passenger added that he looked at the fuel mixture and controls on the left console and recalled that everything was normal. He could not recall what power setting was used during the low pass. The owner of the airplane reported that, the day of the accident, the pilot and passenger boarded the airplane, started the engine, and taxied to the runway. After takeoff, the pilot performed a 180° turn back to the airport and performed a low pass with the landing gear up. The airplane returned to the airport several minutes later and conducted a second pass, with the landing gear in the extended position. He stated that the airplane flew around the pattern and conducted a third pass about 40 ft above the runway with the flaps extended to 10 or 20° and the landing gear extended. Following the pass, the airplane pitched up, in what he called a “not terribly aggressive” climb out. The owner said that he did not see the airplane descend or impact the ground as he was getting back into his vehicle. He estimated that the total duration of the accident flight was about 20 to 25 minutes. PERSONNEL INFORMATIONThe owner stated that the pilot told him he had experience in radial engine powered, tailwheel-equipped airplanes but no experience in a T28. AIRCRAFT INFORMATIONReview of the airframe logbooks revealed that the most recent annual inspection was completed on August 4, 2019, at an airframe total time of 2,378 hours. No engine logbooks were available for review. An airframe and powerplant mechanic who had worked on the airplane reported that he installed a carburetor that the owner had purchased new, and he subsequently conducted a test run of the engine, which included a magneto check, cycling of the propeller, and taxi tests. The mechanic stated that no leaks or other issues were noted. The mechanic who performed the annual inspection on the airplane reported that, during the annual inspection, he went through the airplane and inspected the work other mechanics had performed. The mechanic stated that he had helped set the idle adjustment on the carburetor during the annual inspection. He added that, during the annual inspection, he used the Title 14 CFR 43 appendix B checklist and did not have a specific inspection checklist for the T28. AIRPORT INFORMATIONReview of the airframe logbooks revealed that the most recent annual inspection was completed on August 4, 2019, at an airframe total time of 2,378 hours. No engine logbooks were available for review. An airframe and powerplant mechanic who had worked on the airplane reported that he installed a carburetor that the owner had purchased new, and he subsequently conducted a test run of the engine, which included a magneto check, cycling of the propeller, and taxi tests. The mechanic stated that no leaks or other issues were noted. The mechanic who performed the annual inspection on the airplane reported that, during the annual inspection, he went through the airplane and inspected the work other mechanics had performed. The mechanic stated that he had helped set the idle adjustment on the carburetor during the annual inspection. He added that, during the annual inspection, he used the Title 14 CFR 43 appendix B checklist and did not have a specific inspection checklist for the T28. WRECKAGE AND IMPACT INFORMATIONThe airplane impacted an open field about 0.48 nautical miles west of the departure end of runway 33, as seen in figure 1. Figure 1: Accident site and airport location plot. The debris path was about 77 ft in length and oriented on a magnetic heading about 266°. The first identified point of contact was a ground impression that measured about 1 ft by 2 ft. The left and right main landing gear doors, paint chips, nose landing gear, and right main landing gear were observed along the debris path. The propeller assembly was located adjacent to the main wreckage. The main wreckage came to rest upright on a heading of about 303°. First responders reported that no fuel odor was present following the accident. Both the forward and aft seat controls, including engine controls, remained attached and moved accordingly when the opposite seat controls were moved. The engine was displaced about 30 to 40° downward. The propeller assembly and a portion of the gear reduction nose case was separated. Before recovery of the airplane, 3 gallons of fuel were removed from the right wing and 11 gallons of fuel were removed from the left wing. There was no evidence of a breach in the fuel system. Postaccident examination of the engine revealed no evidence of any mechanical anomalies that would have precluded normal operation. The carburetor was inspected at the facilities of Vintage Carburetors, Tehachapi, California, under the supervision of a Federal Aviation Administration inspector. The carburetor was installed on a test bench and was found to flow within specifications, with the exception of idle. During the idle flow tests, no fuel flow was obtained. The jet cover was removed, and the idle valve was found completely closed with the throttle arm at the idle stop. A company representative stated that it appeared that the idle mixture had been adjusted to a point that completely closed the idle valve. The company representative further stated that the idle valve was the first flow point before the jets, and that the idle valve needs a small gap at the idle stop position. The company representative estimated that, based on this setting, that the accident engine would most likely not run below 1,300 to 1,400 rpm. Following the examination of the carburetor at Vintage Carburetors, the carburetor was further examined. When the throttle arm was moved toward the idle position until the idle valve was nearly closed, the idle side of the throttle arm was about 3/16 inch from the throttle stop, as seen in figure 2. Figure 2: Carburetor idle valve and throttle arm near the idle position.
A total loss of engine power due to the improperly adjusted carburetor idle valve.
Source: NTSB Aviation Accident Database
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