Champion 7-GCB Capsizes During Glacier Landing at Clariden Pass

Casualties unknown • Claridenpass, GL, CH

A Champion 7-GCB aircraft experienced a hard landing and subsequent capsize on the Hüfifirn glacier due to poor visibility of ground altitude.

What happened

On May 9, 1963, a Champion 7-GCB aircraft, operated by the Fluggruppe Mollis, departed from Kloten at 10:20 MEZ. The pilot intended to perform a glacier landing on the Hüfifirn/Planura area near the Clariden Pass. During the approach, the pilot encountered extremely diffuse lighting caused by heavy, layered cloud cover. This lack of visual contrast made it difficult to accurately judge the aircraft's height above the surface. Consequently, the pilot flew through the landing flare at too high an altitude, causing the aircraft to drop sharply. The aircraft struck the firm snow surface with significant force and subsequently overturned.

The investigation

The investigation examined the environmental conditions and the flight profile leading to the accident. At the time of the incident, a cold front was positioned north of the Alps, resulting in high cirrus clouds and diffuse lighting. The investigation also reviewed the aircraft's configuration, noting it was equipped with metal skis (model FLY-LITE) for takeoff and landing operations. The site of the accident was identified as a relatively flat, snow-covered glacier surface at an elevation of approximately 2,950 meters.

Findings

  • The primary cause of the accident was the pilot's misjudgment of altitude during the landing approach.
  • The presence of heavy cloud cover created diffuse lighting conditions, which prevented an accurate assessment of the height above the glacier.
  • The pilot's familiarity with the area may have led to the decision to attempt a landing despite the unfavorable lighting.
  • The impact resulted in no fatalities or injuries to the two occupants, though the aircraft sustained extensive structural damage to the fuselage and wings, estimated at 70% of its value.

Probable cause

The pilot misjudged the aircraft's height above the ground during a glacier landing approach because the diffuse lighting caused by heavy cloud cover obscured the perception of altitude.

Frequently asked questions

What happened in the 1963-05-09 CHAMPION AIRCRAFT CORPORATION 7GCB accident near Claridenpass, GL, CH?

A Champion 7-GCB aircraft experienced a hard landing and subsequent capsize on the Hüfifirn glacier due to poor visibility of ground altitude.

What aircraft was involved and where did it happen?

The accident on 1963-05-09 involved a CHAMPION AIRCRAFT CORPORATION 7GCB, registration HB-UAM, at Claridenpass, GL, CH.

What was the probable cause of the accident?

The pilot misjudged the aircraft's height above the ground during a glacier landing approach because the diffuse lighting caused by heavy cloud cover obscured the perception of altitude.

Investigation report by the Swiss Transportation Safety Investigation Board (STSB / SUST). Original record: https://www.sust.admin.ch/inhalte/AV-berichte/106.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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