Incident Overview
On July 27, 2010, at approximately 1215 central daylight time, a Piper PA-32R-301 (registration N8159B) and a Piper PA-11 (registration N78659) collided while both airplanes were maneuvering over Ripon, Wisconsin. Both aircraft were inbound to Oshkosh (KOSH) to attend the 2010 AirVenture and were flying the FISK visual flight rules (VFR) arrival. Visual meteorological conditions prevailed at the time of the accident. Neither the commercial pilot of N8159B nor the commercial pilot and passenger of N78659 were injured.
Pilot Reports
The pilot of N8159B stated he was monitoring the FISK Approach frequency and heard controllers advise aircraft to “keep their speed up.” He had joined the arrival route west of Ripon at 1,800 feet mean sea level (msl). After hearing the advisory, he increased his airspeed to between 95 and 100 knots. He observed a Cessna one mile ahead and followed it. Approximately two miles east of Ripon, he heard a soft “thud” and then another airplane transmit that an airplane had hit them. He responded that he had hit the other airplane. N8159B continued to KOSH and landed on runway 18 right. During the landing roll, the pilot lost directional control and departed the runway to the left.
In a written statement, the pilot elaborated that before arriving at Ripon, he performed S-turns to scan for traffic and then observed the Cessna. He did not perform S-turns after Ripon because the NOTAM prohibited such action. He stated his altitude was constant at 1,800 feet msl and he was neither climbing nor descending prior to or at the time of impact. He never observed N78659 before the collision. Regarding the controller’s statement to “keep their speed up,” he said it was a general statement repeated several times during the 15 minutes he had been monitoring the frequency.
The pilot of N78659 reported that he was just east of FISK when an airplane struck his airplane from above. The other airplane continued past him to the east, and he reported the collision on the FISK frequency. He noted a vibration in the engine but was able to reduce power and continue to KOSH, performing a straight-in landing to runway 09 without further incident. His written statement added that before flying the required procedure, he performed a 360-degree turn to clear for traffic.
Aircraft Examination
An examination of N8159B revealed damage to the left main landing gear tire and wheel. No further impact damage or anomalies were found in the remaining systems. An examination of N78659 revealed damage to one propeller blade, with no other impact damage or anomalies.
Procedures and NOTAM
Both aircraft were following the FISK VFR arrival procedures for Oshkosh, as communicated through a Federal Aviation Administration Notice to Airmen (NOTAM) effective July 23 through August 2, 2010. The procedures required aircraft at 1,800 feet msl to maintain 90 knots or maximum cruise speed (if slower than 90 knots). After Ripon, aircraft were to follow railroad tracks to FISK and then follow ATC instructions. The NOTAM specifically required a minimum of ½ mile in-trail spacing and prohibited S-turns. Both pilots confirmed they had the NOTAM. According to an Air Traffic Control Manager, when pilots receive an instruction to increase speed, they are not expected to climb to a higher altitude.