AAIB investigation to HPH Glasflugel 304 eS, G-GSGS

Front Electric Sustainer (FES) battery fire during landing, Parham Airfield, West Sussex, 10 August 2017.


During a normal touchdown following an uneventful flight, the glider’s forward FES lithium polymer battery ignited due to an electrical arcing event. The pilot was unaware that the glider was on fire and the battery continued to burn, generating smoke and fumes which entered the cockpit during the latter stages of the landing roll. The pilot was not injured and the fire was extinguished using foam retardant, although the glider’s fuselage battery box and surrounding structure were extensively damaged by the fire.

A comprehensive investigation of the failed battery did not identify the cause of the electrical arcing event. The AAIB published a Special Bulletin, S3/2017, in September 2017 that contained three Safety Recommendations relating to the provision of fire warning systems in FES-equipped sailplanes.

As a result of this investigation the sailplane manufacturer and FES system manufacturer have implemented a number of safety actions intended to prevent recurrence, or to mitigate the effects of a battery fire.

Download report:

HPH Glasflugel 304 eS, G-GSGS 09-18

Download glossary of abbreviations:

Glossary of abbreviations

Download Safety Recommendation document:

Safety Recommendation Document: HPH Glasflugel 304 eS, G-GSGS

Published 13 September 2018