Aviation Accident Summaries

Aviation Accident Summary ANC98FA110

ANCHORAGE, AK, USA

Aircraft #1

N354AM

Yakovlev YAK-54

Analysis

The pilot and a pilot-rated passenger, flying a Russian built unlimited class aerobatic airplane, joined a second aerobatic airplane for a planned photo flight. The two airplanes flew alongside each other while the passengers took photographs. The photo flight altitudes varied between 2,600 and 3,400 feet msl. After the photo session was completed, the pilot of the accident airplane stated he was going to demonstrate some aerobatic maneuvers to his passenger. During a turn, the pilot of the second airplane momentarily lost sight of the accident airplane. When he regained sight of the accident airplane, he estimated it was between 2,700 to 3,000 feet msl, in what appeared to be an inverted right spin. The spin continued for between 5 to 7 turns until the airplane collided with trees. The accident airplane was being operated in the United States under an experimental/exhibition airworthiness certificate. It has light control forces, and a roll rate of 340 degrees per second. No preimpact mechanical malfunction was found. The pilot was an active U.S. Air Force Lt. General with extensive military experience. He had accrued 16.6 hours in the accident airplane. According to his logbook, he had practiced several aerobatic manuevers in the airplane, including incipient inverted spins, and inverted and upright flat spins. The accident pilot and passenger had previously flown aerobatic airplanes together. The passenger had competed in aerobatic airplanes in the past. He did not have any experience in the accident airplane. The airplane flight manual recommends an altitude of 1,500 meters (4,922 feet) prior to initiating spins.

Factual Information

HISTORY OF FLIGHT On July 26, 1998, about 1109 Alaska daylight time, a Russian built, unlimited class aerobatic Yakovlev Yak-54 airplane, N354AM, was destroyed after colliding with trees and terrain on the Fort Richardson Army Base, about 14 miles north of Anchorage, Alaska. The airplane was being operated as a visual flight rules (VFR) local area personal flight under Title 14, CFR Part 91, when the accident occurred. The airplane was registered to Red Eagle Flying LLC, Anchorage, and operated by the pilot/owner. The airplane was operated in the United States under a special airworthiness certificate in the experimental/exhibition category. The certificated commercial pilot, and the pilot-rated passenger, received fatal injuries. Visual meteorological conditions prevailed. The flight originated at the Elmendorf Air Force Base, Anchorage, about 1030. The pilot, a U.S. Air Force Lt. General at Elmendorf AFB, and the passenger, departed Elmendorf AFB and joined a second airplane in restricted airspace R-2203 to photograph each airplane. No airspace restrictions were in effect during the flight. The airspace overlies military reservation land on the Fort Richardson Army Base. The second airplane, a Sukhoi SU-29, N329SU, occupied by the pilot and a passenger, departed from Merrill Field, Anchorage. The pilots and passengers of both airplanes met at Merrill Field about 0930, and conducted a briefing about the photo flight. The briefing included primary and secondary communications frequencies, key landmarks, weather, and emergency landing areas. After the briefing, each pilot departed their respective airports about 1030. After takeoff from Elmendorf AFB, the accident airplane was assigned a transponder code of 0154 by an Anchorage Air Route Traffic Control Center (ARTCC) controller. After departure from Merrill Field, the SU-29 was assigned a transponder code of 0151. The two airplanes rendezvoused in R-2203. Upon reaching the area, the pilot of the SU-29 was told by ARTCC to place his transponder on "standby." The two airplanes then flew alongside each other while the passengers of each airplane took photographs. The pilots of each airplane were seated in the rear seat of their respective airplanes which is the pilot-in-command position. Both seats of each airplane were equipped with full functioning dual flight controls. The pilot of the SU-29 reported that after the photography session was completed, he planned to return to Merrill Field. He began to fly northward about 3,000 feet msl, diverging away from the accident airplane that was flying southbound. During a radio conversation, the pilot of the accident airplane stated he was going to demonstrate some aerobatic maneuvers to his passenger. The pilot and passenger of the SU-29 saw a hammerhead turn to the right, followed by a 4-point roll. The roll was conducted at an altitude lower than the SU-29. While he was making a turn toward the south, the pilot of the SU-29 momentarily lost sight of the Yak-54 airplane. After completing his turn, the pilot of the SU-29 reported he regained sight off the YAK-54. He estimated he was about 3 miles north of the accident airplane. When visual contact was regained with the YAK-54, it was facing north at an altitude higher than what was used for the previous 4-point roll, and the airplane had just entered a spin. The SU-29 pilot said he estimated the altitude of the YAK-54 between 2,700 and 3,000 feet msl, and descending. He said the position of the airplane seemed to indicate the YAK-54 had performed a course reversal, and a gain in altitude, prior to the spin. The spin appeared to be upright, and to the right. The SU-29 pilot estimated the spin rotation around 300 degrees per second, with the nose of the airplane about 70 to 80 degrees below the horizon. The SU-29 pilot described the spin as "normal," but at an altitude lower than he expected. The accident airplane continued to descend in the spin without noticeable variation, for between 5 to 7 turns, until it collided with trees. Both the pilot and passenger of the SU-29 looked for parachutes, but saw none. The SU-29 pilot then made radio contact with the Anchorage ARTCC, and reported the accident. Following the accident, the pilot and passenger of the SU-29 both submitted written descriptions of the accident events. They also provided an addendum to their written statements. Each addendum included a revision of their observations of the accident airplane. After review of photographs of the accident airplane, and comparison between the color of the airplane and their observation of the spin, both occupants of the SU-29 reported the accident airplane appeared to be in an inverted spin. The accident occurred during the hours of daylight at latitude 61 degrees, 20.712 minutes north, and longitude 149 degrees, 39.931 minutes west. CREW INFORMATION The pilot held a commercial pilot certificate with airplane single-engine land, multiengine land, instrument airplane, and glider ratings. In addition, he held a flight instructor certificate with airplane single-engine, and instrument airplane ratings. His most recent second-class medical certificate was issued on February 26, 1998, and contained the limitation that he must wear corrective lenses. The pilot's military career included flying about 40 different models of aircraft, and he had accumulated about 4,400 hours of military flight time. He routinely operated high performance military fighter aircraft. He received "G" awareness training, including centrifuge training, on October 30, 1990. The pilot received a Statement of Aerobatic Competency (FAA Form 8710-7) from the FAA in November, 1996. The pilot's statement of aerobatic competency was issued for solo and formation aerobatics at Level 4 (minimum altitude of 800 feet above the ground), in a L-39/Yak-52 airplane. The pilot applied for the form on November 3, 1996, by undergoing an evaluation from an Airshow Certification Evaluator (ACE). In partnership with the FAA, the ACE program is administered by the International Council of Air Shows, Inc. After evaluation, a pilot's application for an 8710-7 card is reviewed by an FAA inspector who then may issue a card. The card is valid for 12 months. Examination of the pilot's logbook, and review of a recent application for aviation insurance, revealed that his total civil aeronautical experience consisted of about 1,600 hours. In the preceding 90 and 30 days prior to the accident, the logbook listed a total of 42.7 and 22.8 hours respectively. His total Yak-54 flight time was 16.6 hours. His last flight in the Yak-54, prior to the accident flight, was on July 22, 1998, when .8 hours were logged. The pilot received a check-out in a Yak-54 airplane on April 14, 1998. He accrued 2.6 hours of training in the airplane from an aerobatic demonstration pilot employed by the importer of the airplane. During the check-out, the demonstration pilot reported the pilot tended to pull hard on the flight controls during aerobatic maneuvers. After delivering the accident airplane to Anchorage, the demonstration pilot indicated that marginal weather conditions contributed to delays in scheduling additional training time in the airplane. Therefore, the accident pilot received no additional instruction in the airplane. The pilot began flying in the accident airplane on June 21, 1998. He accrued an additional 14.0 hours in the Yak-54 before the accident. The pilot noted the type of aerobatic maneuvers he practiced in the accident airplane in his logbook. These included hammerhead stalls, 4 point rolls, inside and outside loops, upright and inverted stalls, immelmans, torque rolls, snap rolls, vertical rolls, normal spins, incipient inverted spins, and inverted and upright flat spins. The pilot noted having experienced up to +8 Gs and -4 Gs in the accident airplane. The passenger held a commercial pilot certificate with an airplane single-engine land rating, limited to carrying passengers for hire only during daylight, and not more than 50 nautical miles from the point of departure. The most recent second-class medical certificate was issued to the pilot on July 23, 1996, and contained the limitation that the pilot must wear corrective lenses. In addition, the passenger held a private pilot certificate with a glider rating, issued on the basis of, and valid only when accompanied by, South Africa Pilot Certificate 1100. The passenger's pilot logbook revealed no flight time entries after December 31, 1997. The passenger's wife indicated he was still actively flying. The passenger's logbook indicated a total time of 940 hours. He had previously competed in aerobatic competitions, and he had not logged any flight time in a Yak-54. The pilot and the passenger had previously flown together in several airplanes, and had joint ownership in a Yakovlev Yak-52 airplane. The pilot accrued about 195 hours in a Yak-52. The passenger accrued about 67 hours in a Yak-52. AIRCRAFT INFORMATION The airplane was designed by the Yakovlev Design Bureau, Moscow, Russia. It was manufactured by the Saratov Aviation Plant, Saratov, Russia, on August 26, 1997. It is a mid-wing, tailwheel equipped monoplane with tandem seating, and a jettisonable canopy. The airplane is designed for aerobatic training, and unlimited class aerobatic competition. The U.S. importer of the airplane was the Northwest Aerobatic Center, Ephrata, Washington. Personnel from the Yakovlev Design Bureau provided the following information: The airplane is rated for nine positive Gs, and seven negative Gs. It has a roll rate of 340 degrees per second. Yakovlev Design Bureau personnel reported that according to their flight test data, at an aft center of gravity (CG) of 37 percent mean aerodynamic chord (MAC), the airplane exhibited neutral stability, but was easily controlled. At a forward CG of 30 percent MAC, the stick force per G is 4 kg (8.8 pounds). At an aft CG (37 percent MAC), the stick force per G is 1 kg (2.2 pounds). The airplane has an aerodynamic buffet that occurs before a stall. The altitude needed to recover from an upright stall was 820 feet, and 984 feet for an inverted stall. The airplane did not demonstrate any tendency to enter an inadvertent spin during stall testing. Additionally, Yakovlev Design Bureau personnel reported that upright and inverted spins were steep and stable. The angle of attack during a normal spin was 40 to 50 degrees, with a recovery in 1/2 turn. The altitude loss for a 3-turn spin was reported to be 1,969 to 2,133 feet. The altitude loss for a 6-turn spin was 2,625 to 2,789 feet. The load factors during spin recovery did not normally exceed 2.5 Gs. A flat spin had an angle of attack of 60 degrees, with 1 turn for recovery. The altitude loss during a 6-turn flat spin was 2,297 to 2,461 feet. For training purposes, the airplane's flight manual specifies a minimum altitude of 1,500 meters (4,922 feet) prior to initiating spins. According to the airplane's flight manual (First printing, dated June 1, 1996), the airplane has an allowable CG range of 29 to 35 percent MAC. The importer of the airplane reported he obtained a revised allowable aft limit of 36.7 percent MAC from the Yakovlev Design Bureau. The revised aft limit data was also included in information provided to the Safety Board by the Yakovlev Design Bureau. The importer of the airplane converted the CG calculations and CG limits from percent MAC to inches. The datum used for CG calculations is the airplane's firewall. The empty weight of the airplane is 1,766 pounds. The maximum gross weight of the airplane is 2,391 pounds. The importer listed the weight of a parachute as 13 pounds. Review of service range, and endurance data contained in the airplane flight manual, revealed a fuel reserve of 17 kg. The flight manual data indicated 1.5 kg of fuel would be used for engine start, warm-up, and taxi. Three kg of fuel would be used for takeoff and climb to 1,000 meters (3,280 feet). Minimum fuel reserve for a guaranteed seven percent margin, was listed as 9.8 kg of fuel. The importer of the airplane stated an average fuel burn is approximately one liter per minute. The following data was utilized by the National Transportation Safety Board investigator-in-charge (IIC), for CG calculations. One meter equates to 39.37 inches. One liter of fuel equates to .72 kg. One gallon of fuel equates to 2.73 kg. One gallon equates to 3.7854 liters. A MAC of 29 percent equates to 19.92 inches aft of datum. A MAC of 35 percent equates to 23.86 inches aft of datum. A MAC of 36.7 percent equates to 24.97 inches aft of datum. Aircraft empty weight, including oil: 1,766.0 lb. Pilot weight, plus a parachute: 217.0 lb. Passenger weight, plus a parachute: 174.0 lb. The accident flight, from takeoff to the report of accident, was 39 minutes. Three estimated CG calculations were performed: 1. If the airplane departed at maximum gross weight, the maximum allowable fuel load would have been 147.6 liters of fuel (234 pounds). At the time of the accident, the airplane would have contained an estimated 105.4 liters of fuel (167 pounds). The estimated weight of the airplane would be 2,324 pounds, with an estimated CG for this configuration of 23.18 inches. 2. If the airplane contained an estimated fuel load of 80 liters (126.8 pounds), the estimated weight of the airplane at the time of the accident would be 2,283.8 pounds, with an estimated CG of 23.44 inches. 3. If the airplane contained the minimum fuel reserve of 17 kg, which is 23.58 liters (37.4 pounds), the estimated weight of the airplane at the time of the accident would be 2,194.4 pounds, with an estimated CG of 24.06 inches. All of the above examples fall within the allowable CG range data provided by the Yakovlev Design Bureau. The airplane's canopy consists of a fixed windshield at the front edge of the front seat area, and a common hinged canopy for the front and rear seat occupants. The canopy is latched along the left side of the airplane by forward and rear forks that insert into fuselage mounted locks equipped with release handles. The locks are interconnected by bell cranks, rods, and cables. Unlatching of the lock is accomplished by inward pivoting, and then aft rotation of the handle. Movement of either left-side release handle (front or rear seat) will unlatch both left side canopy locks for opening. Movement of one handle will not produce movement of the other handle. The canopy is attached to the right side of the fuselage by two hinged plates with forks, one each in the forward and rear seat areas, that insert and latch into fuselage mounted locks equipped with release handles. The right-side canopy handles are painted red and are labeled: "canopy emergency jettison." By interconnection of the fuselage lock mechanisms, inward pivoting, and then aft rotation of either right-side handle will unlatch all canopy locks, and allow the canopy to be jettisoned. Movement of one right handle will not produce movement of any other handle. Inadvertent inward pivoting and aft rotation of the emergency jettison handles is prevented by installation of soft, copper safety wire, at the base of both right-side canopy handles. The airplane was equipped with an annunciator module in the front instrument panel. It contained annunciator lights for "CANOPY", "GEN OFF", and "CHIP DET." A separate annunciator module was installed in the rear instrument panel. It contained the same annunciator lights as the front seat, with the addition of "PITOT." Each instrument panel had an additional annunciator for "MAX G." Examination of the airplane's airframe and engine logbooks revealed a notation that after manufacture, the airplane accrued 1.9 hours at the factory. The wings were removed, and the airplane was shipped to the Northwest Aerobatic Center for reassembly. The airplane was reassembled on December 5, 1997, in Ephrata, Washington. The pilot registered the airplane with the FAA on May 25, 1998. On June 11, 1998, at 2.2 hours total time since new, the importer of the airplane installed the following items: The rear seat lap belt,

Probable Cause and Findings

The pilot's inadequate remedial action to recover from an inverted spin, while performing aerobatics. Contributing factors were the lower than recommended entry altitude for a spin and the pilot's lack of familiarity with the accident airplane.

 

Source: NTSB Aviation Accident Database

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