Cessna 170B N4590C accident near Palmer, Alaska

Probable cause

The pilot's decision to make a low-altitude pass over a remote airstrip toward rising terrain in weather conducive to downdrafts.

NTSB analysis

The pilot stated that he was maneuvering the airplane following a creek and observed an airstrip below. He decided he would make a practice approach to the airstrip, with no intention of landing. On the second approach, upon reaching the threshold of the landing area, he initiated a climb. After flying the length of the airstrip, the airplane started to descend. The pilot opined that the airplane had entered a downdraft and in response applied full engine power. The airplane continued to descend and collided with rising terrain near the end of the airstrip. The airplane sustained structural damage to its wings and fuselage.

The airplane was equipped with a required emergency locator transmitter (ELT), however, it was an older generation ELT that transmitted only on 121.5 megahertz, not the newer, digital version that transmits on 406 megahertz. As of February 2009, the search and rescue satellites that receive ELT signals no longer had the capability to receive the older analog 121.5 megahertz ELTs. The 406 megahertz ELTs are received within seconds of activation, and rescuers are notified within minutes of the accident location. In this accident, the pilot and passenger were missing for 2 days and a search was initiated. They were able to walk to a trail, despite serious injuries, where a group of all terrain vehicle riders assisted them.

Text from the NTSB. Open the NTSB docket for ANC10LA065 for the full record.