Maule MX7 collides with icy depression during takeoff near Clariden-Hüfifirn

Casualties unknown • Clariden-Hüfifirn, UR, CH

A training flight involving a Maule MX7 ended in an aircraft accident after the plane struck an icy depression during its takeoff roll.

What happened

On November 24, 2015, a Maule MX7, registration HB-KFC, was conducting a training flight near the Clariden-Hüfifirn area. The flight was an introductory session where the instructor maintained full control of the aircraft. After performing several landings at the Hüfifirn-Ost site, the crew scouted a new landing area located slightly to the north. Following several reconnaissance passes, the crew attempted a landing at this new location, which was completed without incident. However, during the subsequent takeoff attempt, the aircraft experienced a significantly slower acceleration than expected. This resulted in an extended takeoff roll, during which the aircraft collided with an icy depression on the terrain. The impact caused the landing gear to collapse and resulted in damage to the wing strut and the propeller. The two crew members sustained light injuries.

The investigation

Investigators examined the circumstances surrounding the takeoff at the newly identified landing site. The inquiry focused on the flight dynamics during the takeoff roll and the environmental conditions of the terrain. The investigation confirmed that the aircraft was operating under VFR rules and that the flight was a training mission. The physical damage to the Maule MX07—specifically the bent propeller, broken wing strut, and collapsed gear—was consistent with the impact with the uneven, icy surface.

Probable cause

The aircraft struck an icy depression during an extended takeoff roll caused by insufficient acceleration.

Frequently asked questions

What happened in the 2015-11-24 MAULE AIRCRAFT CORPORATION MX-7-235 accident near Clariden-Hüfifirn, UR, CH?

A training flight involving a Maule MX7 ended in an aircraft accident after the plane struck an icy depression during its takeoff roll.

What aircraft was involved and where did it happen?

The accident on 2015-11-24 involved a MAULE AIRCRAFT CORPORATION MX-7-235, registration HB-KFC, at Clariden-Hüfifirn, UR, CH.

What was the probable cause of the accident?

The aircraft struck an icy depression during an extended takeoff roll caused by insufficient acceleration.

Investigation report by the Swiss Transportation Safety Investigation Board (STSB / SUST). Original record: https://www.sust.admin.ch/inhalte/AV-berichte/HB-KFC.pdf. This page is a structured re-presentation; facts and quotes are in the Swiss Transportation Safety Investigation Board (STSB), Switzerland.

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