Aviation Accident Summaries

Aviation Accident Summary CHI03LA280

Wichita, KS, USA

Aircraft #1

N55326

Cessna 172P

Analysis

The airplane was substantially damaged during an encounter with jet blast while taxing to the ramp after landing. The student pilot reported that she had landed and was instructed by the tower controller to exit at a specific taxiway and taxi to parking. The pilot stated there was a Challenger jet aircraft parked on an intersecting taxiway which the assigned taxi route required her to pass behind. The pilot reported that as she taxied behind the Challenger, her aircraft "started vibrating beyond control, moved around on the taxi way and [she] was unable to continue taxiing." The pilot stated that in the process, the right wing and propeller hit the pavement. Radio conversations between the control tower and the aircraft revealed that the Challenger requested a taxi clearance to perform "maintenance runs." The Challenger crew consisted of mechanics who were conducting a run-up to verify proper engine operation. They reported they were positioned on a crossing taxiway, 40 - 60 feet from the intersection at which the accident occurred. After the accident, the Challenger crew stated that they were operating above idle. The tower reportedly did not question them about their proximity to the crossing taxiway. At the time of the accident, an airport operating instruction concerning aircraft engine testing and run-up was in effect. It stated that aircraft "shall be positioned so as to provide the least amount of interference with other taxiing aircraft, and where jet or propeller blast will not affect parked or taxiing aircraft." The Challenger aircraft operating manual specifies hazard areas regarding engine exhaust. At idle thrust, the exhaust stream hazard area extends to approximately 85 feet behind the engine. At a distance of 40 feet, the exhaust stream speed is 34 miles per hour. At maximum thrust, the hazard area exceeds 170 feet. Exhaust stream velocity is 272 miles per hour approximately 38 feet behind the engine and is 136 miles per hour at a distance of approximately 58 feet. An individual of the maintenance facility stated that the company did not have a formal training procedure for mechanics regarding aircraft ground operations and jet blast hazards.

Factual Information

On August 23, 2003, at 1100 central daylight time, a Cessna 172P, N55326, operated by the Cessna Employee's Flying Club and piloted by a student pilot, was substantially damaged during an encounter with jet blast while taxing to the ramp after landing at the Wichita Mid-Continent Airport (ICT), Wichita, Kansas. The solo instructional flight was conducted under the provisions of 14 CFR Part 91 without a flight plan. Visual meteorological conditions prevailed at the time of the accident. The pilot reported no injuries. The flight reportedly departed the Wellington Municipal Airport at 1040. According to the pilot's written statement, she had landed on runway 19L and was instructed by the ICT tower controller to exit on taxiway A7 and taxi to parking. The pilot stated there was a Challenger jet airplane, N653CW, on taxiway AA, just south of A7. The pilot reported that as she taxied behind the Challenger, her aircraft "started vibrating beyond control, moved around on the taxi way and [she] was unable to continue taxiing." The pilot stated that in the process, the right wing and propeller hit the pavement. Radio conversations between the ICT air traffic control tower and the aircraft involved were reviewed. They revealed that the Challenger requested a taxi clearance to taxiway AA in order to perform "maintenance runs." The ICT ground controller cleared them to taxi as requested. The accident aircraft was subsequently cleared to exit the runway at taxiway A7 and taxi to parking as noted in the pilot's statement. After the accident, the Challenger crew was asked by the ground controller if they were performing above idle engine run-ups. The mechanics stated that they were and the controller requested they stop. The Challenger was relocated to the next taxiway intersection to continue the maintenance runs. The Challenger crew consisted of mechanics from Wichita Executive Aircraft located at ICT. The aircraft was reportedly undergoing maintenance by Wichita Executive Aircraft at the time of the accident. According to the mechanics' statement, they were conducting a run-up to verify proper engine operation. They reported they were positioned on taxiway AA, 40 - 60 feet south of taxiway A7. The ICT tower reportedly did not question them about their proximity to taxiway A7. They had been at that location about 15 minutes when they were instructed to move further south on the taxiway. They reported they had no knowledge of the accident until airport safety personnel informed them when they exited the aircraft to make engine adjustments. Wichita Mid-Continent Airport Operating Instruction #14, concerning aircraft engine testing and run-up, stated that aircraft "shall be positioned so as to provide the least amount of interference with other taxiing aircraft, and where jet or propeller blast will not affect parked or taxiing aircraft." In addition, the instruction stated that the "aircraft owner, operator, or airport tenant having responsibility for the aircraft shall be responsible to the Wichita Airport Authority (WAA) for compliance under this Operating Instruction." The Operating Instruction stated that small aircraft may conduct engine run-ups on Taxiway AA. However, it required large aircraft to conduct daytime run-ups on Taxiway D, between Taxiways C and CC. The instruction did allow the ICT control tower to direct aircraft to other areas for engine run-ups based on operational requirements and traffic demand at the time. Federal Aviation Administration (FAA) records listed N653CW as a Canadair Ltd. [Bombardier] CL-600-2B16 [Challenger] aircraft (serial no. 5053). The aircraft was owned by Flight Options LLC of Richmond Heights, Ohio. According to the FAA Type Certificate Data Sheet, the aircraft was powered by two General Electric CF-34 series turbofan engines. Each engine was capable of producing 8,650 lbs. static thrust at takeoff. The aircraft's maximum certificated takeoff weight was listed as 43,100 lbs. The Challenger Operating Manual specifies hazard areas regarding engine exhaust. At idle thrust, the exhaust stream hazard area extends to approximately 85 feet behind the engine. At a distance of 40 feet, the exhaust stream speed is 34 miles per hour. At maximum thrust, the hazard area exceeds 170 feet. Exhaust stream velocity is 272 miles per hour approximately 38 feet behind the engine, and is 136 miles per hour at a distance of approximately 58 feet. FAA Advisory Circular 65-9A, Airframe and Powerplant Mechanics General Handbook, provides general guidance for mechanics during ground operations. Figure 11-1, engine intake and exhaust hazard areas, notes that typical turbojet engine exhaust hazard areas extend up to 100 feet behind the engine at idle, and up to 200 feet at takeoff thrust. According to 14 CFR Part 1, the FAA has defined a "large aircraft" as an "aircraft of more than 12,500 pounds, maximum certificated takeoff weight." A representative of Wichita Executive Aircraft stated that the facility had no formal procedure for training mechanics for aircraft ground operations at the time of the accident. He noted that mechanics are briefed by pilots rated on the aircraft or other mechanics who have previously been checked out on that particular aircraft. This procedure was not specifically documented, according to the individual. He added that since the accident, procedures regarding aircraft operations by company mechanics have not changed.

Probable Cause and Findings

Failure of the maintenance crew to provide adequate clearance to an active taxiway during the engine run-up. Contributing factors were the failure of the control tower to provide a wake turbulence advisory to the accident aircraft when assigning a taxi route crossing immediately behind the maintenance aircraft, and the failure of the maintenance facility to have a formalized training procedure regarding aircraft ground operations and jet blast hazards for company mechanics.

 

Source: NTSB Aviation Accident Database

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