A fire at a power substation that led to the cancellation of more than 1,300 flights at the UK’s Heathrow Airport was caused by a preventable technical fault identified almost seven years earlier, according to a report released on Wednesday.
The report by the National Energy System Operator stated that an "elevated moisture reading" had been detected in oil samples at the substation in west London in July 2018. However, no action was taken to replace the electrical insulators, commonly referred to as bushings.
