NTSB Factual Report

On November 30, 2001, at 1546 Pacific standard time, an Air Tractor AT-401B, N9186J, landed on top of an Air Tractor AT-402A, N139LA, on runway 19R at the McCarren International Airport, Las Vegas, Nevada. The AT-402A sustained substantial damage to the rudder, while the AT-401B sustained minor damage. Neither the commercial pilot onboard the AT-401B, or the airline transport pilot onboard the AT-402A were injured. The AT-401B was registered to Southeastern Aerial Corp Service Inc., Fort Pierce, Florida, and the AT-402A was registered to Air Tractor Inc., Olney, Texas. Air Tractor operated both airplanes under the provisions of 14 CFR Part 91. The two airplanes were part of a flight of three airplanes that departed the Olney Municipal Airport, Olney, approximately 0845 en route to Las Vegas, where the airplanes were to be displayed at the National Agricultural Aviation Association's annual convention. Visual meteorological conditions prevailed at the time of the accident, and a flight plan had not been filed for the cross-country flight.

For purposes of this report, the three airplanes will be referred to as the AT-401, AT-402, and AT-502.

According to the AT-401 pilot, the AT-401 was equipped with a "ferry radio package that contained a single com[munication] radio and transponder with encoder." The pilot tested the radio with a radio check over the unicom frequency located at the departure airport. The AT-401 pilot indicated the response to his radio check was, "loud and clear."

The AT-401 pilot experienced a gradual loss of radio communication capability when the flight neared Albuquerque, New Mexico (ABQ). The ABQ approach controller indicated the airplane's communications were, "weak, but readable." The AT-401 pilot could hear the communications from the AT-502 pilot; however, he could not hear any communications from AT-402 pilot. The AT-401 pilot indicated that communications were possible (on a limited basis) when the airplanes were aligned adjacent to each other; however, no communications were possible if the airplanes were in trail.

As the flight of three neared its destination, with the AT-401 in lead, the AT-402 next, and the AT-502 in the trailing position, plans were made to enter Las Vegas' class C airspace. It was determined that if the AT-401 could not establish communications with Las Vegas air traffic control, the AT-502 would take the lead, establish communications for the three airplanes, and take the flight to the runway.

The AT-401 could not establish communications with Las Vegas approach control and the lead was transferred to the AT-502. The AT-401 then took up the number 2 position echelon off the AT-502 right wing. The AT-401 pilot changed radio frequencies, along with the AT-502. The AT-502 pilot relayed to the other pilots the headings assigned by air traffic control.

The AT-401 pilot indicated that as they approached the airport, the sun was low on the horizon and "now a factor in visibility." Approach control had cleared the flight of three to make a left base approach to runway 19R. The AT-401 pilot made visual contact with the number 3 airplane (AT-402), and determined he was "roughly in trail with the lead aircraft, several hundred yards behind."

As as the AT-401 turned from base leg to final, the AT-401's heading passed through the glare of the setting sun. The AT-401 pilot maintained his position relative to the lead aircraft (AT-502). He indicated he followed the lead aircraft onto final, landed behind it, and taxied off the active runway.

According to the AT-402 pilot, he was originally in the number 2 position behind the AT-401; however, when the AT-401 experienced radio communication problems, a plan was made to deal with the situation. The AT-402 pilot indicated that plan "A" would be: if the AT-401 pilot obtained airspace clearance, then the landing order would be the AT-401, followed by the AT-402, and then the AT-502. However, as the radio communications degraded on the AT-401, the plan was changed to plan "B," which had the AT-502 obtain the clearance and land, followed again by the AT-402, then the AT-401. The AT-402 remained in the number 2 position in both plans.

The AT-402 pilot indicated he landed number 2 behind the AT-502, and was rolling out with all wheels firmly on the ground, when he felt the aircraft shudder. He observed both main wheels of the AT-401 "come past the cockpit, flying exactly over the top of me." The AT-401 was flying straight and level and landed ahead of the AT-402. The AT-402 pilot scanned his instrument panel, powered up, taxied clear of the runway, and parked the airplane.

The pilot of the AT-401 reported he had 2 years (and approximately 200 hours) of formation flying experience in T-6 trainers with the Confederate Air Force.

In the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), under the section titled "Recommendation (How Could This Accident Have Been Prevented," the AT-401 pilot listed "formal formation training and qualification check for all pilots in group. Proper installation of ferry radio equipment."

NTSB Probable Cause

the failure of the AT-401 pilot to maintain clearance with the AT-402 airplane during landing. Contributing factors were the unreliable communication radio in the AT-401, the AT-401 pilot's continued flight with known communication radio problems, and the glare of the sun.