Wet grass, no brakes bad combination

Aircraft: Piper Cherokee Six. Injuries: 1 Serious,1 Minor. Location: Elkader, Iowa. Aircraft damage: Substantial.

What reportedly happened: According to the pilot, he approached the intended destination airport and descended from 5,500 feet to 2,000 feet MSL in order to remain clear of clouds. The airplane encountered light rain and reduced forward visibilities during the approach.

The pilot lost sight of the destination airport so he performed a 180° turn in preparation of diverting to an alternate airport. During the turn he realized that the weather had closed-in behind him so diverting was not an option. He continued the turn and was able to spot the destination airport again as the clouds had moved on.

The pilot entered a left traffic pattern for runway 17, which was a grass runway measuring 1,705 feet long. The grass was wet because of the recent rain. The pilot stated he touched  down on the first third of the runway, and found the braking action was nil. He applied full power with the intent to abort the landing. The airplane lifted off.

The pilot was able to out climb trees located off the departure end of the runway, but could not stop the airplane as it settled into more trees, and then went down a 100-foot slope into a ravine.

An on-site investigation found tire marks on the grass runway consistent with the tire width of the accident airplane. The first of these tire marks was more than halfway down the 1,705-foot-long runway, about 741 feet from the departure end. These tire tracks continued past the departure threshold until a point where the terrain sloped away from the runway elevation, indicating that the airplane had not become airborne on the usable runway.

The physical evidence was consistent with the airplane running off the end of the runway before descending into treetops that were at or below the runway elevation.

Review of available performance data indicated that the expected landing distance for a wet grass runway would be in excess of 748 feet. Investigators determined the landing performance calculations in the aircraft’s POH indicated that there was sufficient runway available for a ground roll if the pilot had touched down within the first half of the runway.

Investigators also determined that based on the available weather radar data and witness observations, localized instrument flight rule conditions likely existed due to thunderstorms and heavy rain in the vicinity of the airport.

Probable cause: The pilot’s failure to attain the proper touchdown point while landing on the wet grass runway.

NTSB Identification: CEN12LA441

This July 2012 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.

 

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