Aviation Accident Summaries

Aviation Accident Summary ANC04FA016

Peoria, AZ, USA

Aircraft #1

N2094M

Piper J3C-65

Aircraft #2

N274KS

Schleicher ASK-21

Analysis

The commercial certificated pilot of an aerobatic glider, with one passenger, was performing a series of aerobatic maneuvers within an aerobatic box, which was adjacent to runway 5L at an uncontrolled airport. The aerobatic box measured 1 kilometer square, and extended from the surface up to 6,600 feet msl (5000' agl). The southern boundary of the aerobatic box was located about 1,490 feet north of runway 5L's centerline. Concurrently, a Piper J3C airplane with the commercial pilot/flight instructor/airplane owner seated in the front seat, and a private pilot seated in the rear seat, departed runway 5L, and made a left downwind turn into the area where the glider was performing the aerobatic maneuvers. Witnesses said that as the glider reached the top of the loop, the nose lowered, eventually pointing straight down. As the glider began to recover from the maneuver, about 600 feet agl, the left wing of the oncoming Piper struck the tail of the glider between the empennage and the main fuselage, severing the empennage of the glider. Witnesses said that during the collision, a large portion of the left outboard wing of the Piper separated, and both the glider and the Piper entered uncontrolled descents. Both aircraft came to rest close to the center of the aerobatic box. According to the airport facilities directory, aircraft departing from runway 5L, are instructed to fly a right-hand traffic pattern. However, the airport's segmented circle depicts a left-hand departure from runway 5L. Radio equipped aircraft may utilize a common traffic advisory frequency of 122.9 Hz. Neither of the aircraft involved in the accident had a radio, nor were they required to. The front seat pilot of the Piper had based the accident airplane at the accident airport for several years, and was familiar with the procedures for operating at the airport.

Factual Information

HISTORY OF FLIGHT On December 28, 2003, about 1312 mountain standard time, a wheel-equipped Piper J3C-65 airplane, N2094M, and a Schleicher ASK-21 aerobatic glider, N274KS, were destroyed during a midair collision, about one-half mile north of the Pleasant Valley Airport, Peoria, Arizona. The two occupants of the Piper, and the two occupants of the glider, were fatally injured. The aircraft collided after the Piper departed runway 5L at the Pleasant Valley Airport about 1310, and turned southwest, into the area where the glider was performing aerobatic maneuvers. Witnesses reported that following the collision, both aircraft entered uncontrolled descents and impacted the desert terrain north of the airport. The private pilot of the Piper was seated in the rear seat, and the airplane owner, a commercial pilot and certificated flight instructor, was seated in the front seat. The Piper was being operated under Title 14, CFR Part 91, as a local area personal flight. According to the Federal Aviation Administration (FAA) Medical Records Center, the airplane owner did not possess a current airman's medical certificate. The Schleicher glider was operated by the Turf Soaring School, Peoria, under Title 14, CFR Part 91, as an instructional/demonstration flight. The pilot of the Schleicher glider, a commercial glider pilot and certificated flight instructor, was seated in the rear seat, and the passenger was seated in the front seat. The glider departed the Pleasant Valley Airport about 1250. Visual meteorological conditions prevailed, and no flight plans were filed. During the on-scene investigation on December 29, witnesses familiar with powered airplane and glider operations near the accident airport, related to the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) that the Piper departed runway 5L, made a climbing left turn, and leveled off at pattern altitude, or about 600 feet agl (above ground level). The witnesses said that the left turn continued until the airplane was on a southwesterly heading, consistent with a left downwind approach for a landing on runway 5L. Concurrently, the Schleicher glider was performing aerobatic maneuvers in an area located to the north of the Pleasant Valley Airport, within an area known to local pilots as the "aerobatic box," which measures 1 kilometer square, and extends from the surface up to 6,600 feet msl (5000 feet agl). The southern edge of the aerobatic box was located about 1,490 feet north of the centerline of runway 5L at the Pleasant Valley Airport. Witnesses reported to the NTSB IIC that as the Schleicher glider was performing a loop, the glider climbed to an altitude of about 800 feet agl, above the path of the southbound Piper. The witnesses said that as the Schleicher glider reached the top of the loop, the nose lowered, eventually pointing straight down. As the glider began to recover from the maneuver, about 600 feet agl, the left wing of the oncoming Piper struck the tail of the Schleicher glider between the empennage and the main fuselage, severing the empennage of the glider. The witnesses said that during the collision, a large portion of the left outboard wing of the Piper separated. PERSONNEL INFORMATION Piper J3C-65: Both occupants of the Piper were certificated pilots, and both pilots had access to the airplane's flight controls. Front seat pilot: The airplane owner, was seated in the front seat, and held a commercial pilot certificate with airplane single-engine land and multi-engine land ratings. He also held a current flight instructor certificate with airplane single-engine land and instrument ratings. A review of the pilot's medical records on file with the Federal Aviation Administration (FAA) Aerospace Medical Certification Division, located in Oklahoma City, Oklahoma, revealed that the front seat pilot's most recent (expired) second-class medical certificate was issued to the pilot on February 28, 2001. According to the FAA records, and due to the pilot's medical history, the medical certificate was issued in accordance with an "authorization for special issuance." The medical certificate contained the limitation/restriction "Not valid for any class after February 28, 2002." On February 8, 2003, the front seat pilot applied for a replacement second-class medical certificate. A review of the pilot's medical application noted in section 19, when asked: "Visits to health professional within Last 3 Years?" The pilot checked "Yes" and noted that on August 10, 2002, he underwent open-heart surgery, for a triple bypass heart operation. According the FAA medical records, the examining physician forwarded the pilot's FAA medical application to the FAA's Aerospace Medical Certification Division. The examining physician did not issue the pilot a replacement medical certificate, but instead "deferred" the front seat pilot's medical application to the Aerospace Medical Certification Division for further review and consideration. In a letter dated September 23, 2003, the manager of the FAA's Aerospace Medical Certification Division requested additional supporting medical information from the front seat pilot, including a current treadmill stress test. According to the medical records obtained by the NTSB, the pilot did not provide the requested additional information to the FAA's Aerospace Medical Certification Division. According to the FAA, at the time of the accident, the front seat pilot did not possess a current FAA medical certificate. According to the pilot's application for medical certificate, dated February 8, 2003, the front seat pilot indicated that his total aeronautical experience consisted of about 14,000 hours, of which 70 were accrued in the previous 6 months. According to a personal acquaintance of the front seat pilot/owner, the accident airplane had been based and operated out of the Pleasant Valley Airport for several years. He added that the front seat pilot was a friend of the glider pilot, and that both pilots regularly attended various social functions at the Pleasant Valley Airport. Rear seat pilot: The rear seat pilot held a private pilot certificate with airplane single-engine land ratings. He also held an instrument airplane rating. The most recent third-class medical certificate was issued to the pilot on December 5, 2003, and contained the limitation that the pilot must have corrective lenses for near vision. According to the pilot's logbook, his total aeronautical experience consisted of about 819.8 hours, with no flight activity being recorded between August 30, 1998 and December 13, 2003, or 15 days before the accident. According to an entry made in the rear seat pilot's logbook, he received a biennial flight review (BFR) from the front seat pilot on December 13, 2003. In the preceding 30 days prior to the accident, the logbook lists a total of 2.6 hours. The rear seat pilot did not have a current tailwheel endorsement. Schleicher ASK-21 aerobatic glider: The Schleicher glider pilot held a commercial pilot certificate with a glider rating. In addition, he held an airplane single-engine land rating limited to private privileges. According to medical records on file with the Federal Aviation Administration (FAA) Aerospace Medical Certification Division, the glider pilot did not possess a current FAA medical certificate, nor was one required for the operations being conducted at the time of the accident. No personal flight records were located for the glider 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 located in Oklahoma City. On the pilot's last application for medical certificate, dated August 16, 2000, the pilot indicated that his total aeronautical experience consisted of 2,500 hours. AIRCRAFT INFORMATION Piper J3C-65: An examination of the Piper's airframe logbook revealed the airplane was manufactured on October 31, 1946. The most recent annual inspection was conducted on May 8, 2003. At that time, the airframe logbook listed a total time of 3,574.9 hours. Schleicher ASK-21 aerobatic glider: According to the NTSB Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1) submitted by the glider operator, an annual inspection had been complied with on September 01, 2003. In addition, a 100-hour inspection had been complied with on November 10, 2003. At the time of the 100-hour inspection, the glider's airframe total time was 10,123.4 hours METEOROLGICAL INFORMATION Witnesses to the accident reported to the NTSB IIC that weather conditions at the time of the accident were, in part: Wind, light and variable; visibility, about 50 miles; clouds and sky condition, clear; temperature, 70 degrees F. COMMUNICATIONS There is no control tower located at the Pleasant Valley Airport. Radio equipped aircraft utilize a common traffic advisory frequency (CTAF) of 122.9 Hz. Neither of the aircraft involved in the accident were equipped with a radio, nor were they required to be. AERODROME AND GROUND FACILITIES The Pleasant Valley Airport is owned by the State of Arizona, which leases the airport to the Turf Soaring School. The published elevation of the airport is 1,580 feet msl. In addition to the Turf Soaring School's gilders and tow airplanes, there are other single engine airplanes, gliders, and ultra light aircraft based at the airport. The airport is equipped with three parallel runways on a 050/230-degree magnetic orientation, and a single dirt-covered runway on a 140/320-degree magnetic orientation. All three parallel runways are 4,200 feet long by 100 feet wide. Runways 14/32 are 2,400 feet long, by 100 feet wide. According to the southwestern airport facilities directory, aircraft departing from runway 5L, the same runway that was used by the departing Piper, are instructed to fly a right-hand traffic pattern. However, during the IIC's review of an aerial photograph of the Pleasant Valley Airport dated September 30, 2003, it was discovered that the airport's segmented circle, located in the center of the airport, adjacent to the intersection of runways 5L and 23, depicts a left-hand traffic pattern when departing from runway 5L. The southwestern airport facilities directory also states that there is aerobatic activity on, and in the vicinity of the airport, and that simultaneous operations on any two runways are not authorized. Adjacent to, and about 1,490 feet north of the centerline of runway 5L, is the southern boundary of the "aerobatic box," which measures 1 kilometer square, and extends from the surface up to 6,600 feet msl, or 5000 feet agl. According to the FAA, the airspace within the aerobatic box, under a certificate of waiver or authorization, is issued to the management of Turf Flying School every two years. The Turf Soaring School utilizes the aerobatic box for training and exhibition of aerobatic gliders. In addition, the certificate of waiver allows Turf Flying School to conduct aerobatics below 1,500 feet agl, which is otherwise prohibited under Federal Aviation Regulations (FAR) 91.303 (e). The aerobatic box is marked on the desert floor by a series of bright white panels that are readily visible while airborne. According to Turf Soaring School management personnel, the owner calls the Prescott Terminal Radar Approach Control (TRACON) each morning to request the activation of the aerobatic box. According to FAA personnel, the aerobatic box was active at the time of the accident. When the aerobatic box is active, the Prescott FSS issues a notice to airmen (NOTAM) concerning the status of the aerobatic box. During preflight weather briefings for pilots operating from, or near the Pleasant Valley Airport, or otherwise upon request, NOTAM advisories are provided concerning the flight restriction within the aerobatic box. There was no record of either pilot of the Piper having requested NOTAM information, or receiving a preflight weather briefing on the day of the accident. A copy of the U.S. Department of Transportation's (FAA) Certificate of Waiver or Authorization, concerning the aerobatic box at the Pleasant Valley Airport, is included in the public docket for this accident. WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board investigator-in-charge (IIC) examined the wreckage at the accident site on December 29, 2003. The wreckage of the Piper was located about 400 feet to the north of the Schleicher glider. Both aircraft came to rest in an area of dry, saguaro cactus-covered desert, and close to the center of the aerobatic box. Witnesses consistently reported that during the in-flight collision, a 4-foot section of the Piper's left wing and left aileron were torn away, along with the entire empennage section of the Schleicher glider. The 4-foot section of Piper wing and aileron, and the Schleicher glider's empennage, were discovered lying on the desert floor directly below where the witnesses described the collision occurred. Piper J3C-65: The wreckage of the Piper exhibited extensive ground impact damage. The fuselage of the airplane was observed in a near vertical, nose down attitude. The longitudinal axis of the fuselage was oriented on a magnetic heading of 210 degrees. (All heading/bearings noted in this report are oriented toward magnetic north.) Except for the 4-foot section of the left outboard wing, all of the Piper's major components were found at the main wreckage area. Both wings had extensive spanwise leading edge aft crushing, and were oriented with the leading edge down, on about a 45-degree angle. The right wing lift struts remained attached to the wing and lower fuselage attach points. The lower portions of both right wing struts appeared to have been cut during rescue attempts. The left wing lift struts remained attached to the wing and fuselage attach points. The wing carry-through was broken, and crushed in an aft direction. The fuselage was buckled just aft of the rear window. Except for the missing left aileron, the flight control surfaces remained connected to their respective attach points. Due to impact damage, the flight controls could not be moved by their respective control mechanisms, but continuity of the flight control cables were established to the cabin/cockpit area. The propeller remained attached to the engine crankshaft. One propeller blade exhibited slight torsional twisting, and significant aft bending about 4 inches inboard from the tip. The second blade had about 70 degree aft bending, about 8 inches outboard from the hub, and slight torsional twisting. The engine cowling, fuselage firewall, and the instrument panel were crushed and displaced aft. The engine was partially buried in the ground at about a 45-degree angle. It sustained impact damage to the underside, and lower front portion of the engine. The engine oil sump was crushed upward against the case. The exhaust tubes were crushed and folded, producing sharp creases that were not cracked or broken along the crease. There were no preaccident mechanical anomalies noted with the accident airplane. Schleicher ASK-21 aerobatic glider The wreckage of the Schleicher glider was located about 400 feet south of the Piper wreckage. The wreckage of the Schleicher glider exhibited extensive ground impact damage. The fuselage of the airplane was observed lying inverted, with the longitudinal axis of the fuselage oriented on a magnetic heading of 140 degrees. Except for the empennage section that was severed during the in-flight collision, all of the Schleicher glider's major components were found at the main wreckage site. Both wings had extensive spanwise leading edge aft crushing. The right wing remained attached to the fuselage, but was fractured about 6 feet inboard from the wing tip. The left wing remained attached to the fuselage, but was fractured about 2 feet inboard from the wing tip. The left wing exhibited extensive spanwise leading edge aft crushing. The nose and front seat passen

Probable Cause and Findings

The inadequate visual lookout by the pilots of both aircraft, which resulted in their failure to see-and-avoid each other's aircraft and a subsequent midair collision. A factor associated with the accident was the airplane pilot's failure to determine that the aerobatic box was in use by the glider prior to his entry into the aerobatic box.

 

Source: NTSB Aviation Accident Database

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