Hesperia, CA, USA
N1014A
Alfred Long-EZ
The airplane collided with a fence while on final approach to the destination airport. While aligned on the final approach leg of the traffic pattern, the airplane encountered a downdraft, and the pilot attempted to increase the engine power and recover from the sudden descent. The airplane collided with a fence that was at the approach end of the runway then slid about 100 yards down the pavement before coming to rest off the right side of the runway surface. The pilot reported no preimpact mechanical malfunctions or failures with the airframe or engine. The Airport/Facility Directory, Southwest U. S., indicated that the runway was 3,910 feet long and 50 feet wide, with a displaced threshold of 500 feet. The runway had an upsloping gradient, which was not noted in the directory. A Federal Aviation Administration publication states that a "narrower-than-usual runway can create the illusion that the aircraft is at a higher altitude than it actually is." It further states that a pilot who fails to recognize this illusion will "fly a lower approach, with the risk of striking objects along the approach path or landing short." The publication also addresses runway and terrain slopes illusions, stating that an, "upsloping runway, upsloping terrain, or both, can create the illusion that the aircraft is at a higher altitude than it actually is." Again, it warns that pilots who fail to recognize this illusion will fly a lower approach.
HISTORY OF FLIGHT On July 11, 2006, about 1015 Pacific daylight time, an Alfred Long-EZ, N1014A, collided with a fence while on final approach to Hesperia Airport, Hesperia, California. The pilot/owner was operating the airplane under the provisions of 14 CFR Part 91. The commercial pilot, the sole occupant, sustained minor injuries; the airplane sustained substantial damage. The personal local area flight departed from Apple Valley Airport, Apple Valley, California, about 0900. Visual meteorological conditions prevailed, and a flight plan had not been filed. In a written statement, the pilot reported that he purchased the airplane 5 days prior to the accident. Following the sale, the previous owner, who was a certificated flight instructor (CFI), provided the pilot with 3 hours of dual instruction consisting of a familiarization checkout. The pilot flew about 3.5 hours between receiving instruction and the accident. The day of the accident, the pilot performed three touch-and-go practice takeoffs and landings at his home base of Apple Valley. He then departed to Big Bear City Airport, Big Bear, California, where he performed a full-stop landing. He taxied back to the active runway, and departed the airport en route to Hesperia. He noted that he had landed at the airport before in other airplane models, the last time being in early May 2006. The pilot further stated that as he entered the vicinity of the airport he observed that the wind was from the south, and opted to land on runway 21. While on final approach, the airplane encountered a downdraft, and the pilot pushed the throttle control forward in an attempt to increase the engine power and recover from the sudden descent. The airplane collided with a fence that was located at the approach end of the runway. The airplane descended in a flat attitude toward the runway asphalt, and skid about 100 yards before coming to rest off the right side of the runway surface. The pilot reported no preimpact mechanical malfunctions or failures with the airframe or engine. METEOROLOGICAL INFORMATION The pilot reported that the winds at the time of the accident were from 180 degrees at 15 knots and gusting to 20 knots. The closest official weather observation station was Ontario International Airport, Ontario, California, which was 24 nautical miles southwest from Hesperia. The airport's 0953 weather observation noted in part, winds from 210 degrees at 4 knots. A local Hesperia weather reporting station recorded the wind conditions at the time of the accident to be as follows: wind from the south-southwest at 2 miles per hour (mph), gusting to 10 mph. AERODROME INFORMATION The Airport/Facility Directory, Southwest U. S., indicated Hesperia runway 21 was 3,910 feet long and 50 feet wide, with a displaced threshold of 500 feet. The runway surface was composed of asphalt. There was no mention of the upsloping gradient of the runway. Accident History A review of previous accidents at Hesperia was conducted by searching the National Transportation Safety Board database. There were a total of seven accidents that occurred at the airport where the pilot impacted an object or misjudged the flare while attempting to land on runway 21. ADDITIONAL INFORMATION The Federal Aviation Administration's (FAA) Airman Information Manual (AIM) addresses illusions encountered on approaches to landing in chapter 8-1-5. It states that a "narrower-than-usual runway can create the illusion that the aircraft is at a higher altitude than it actually is." It further states that a pilot who fails to recognize this illusion will "fly a lower approach, with the risk of striking objects along the approach path or landing short." The AIM chapter additionally addresses runway and terrain slopes illusions, stating that an, "upsloping runway, upsloping terrain, or both, can create the illusion that the aircraft is at a higher altitude than it actually is." Again, it warns that pilots who fail to recognize this illusion will fly a lower approach.
The pilot's failure to maintain the proper glide path on final approach as a result of the visual illusions created by a narrow, upsloping runway.
Source: NTSB Aviation Accident Database
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