London Fire Brigade<\/figcaption><\/figure>\nIAG said the outage had an \u201cadverse impact\u201d, causing a circa 1% hit to its expected earnings in the first three months of the year.\u00a0<\/p>\n\n
\u201cThe impact of the closure of London Heathrow Airport on 21 March increased non-fuel unit costs by approximately one percentage point,\u201d said IAG.\u00a0\u00a0<\/p>\n
On May 8, 2025, National Energy System Operator (NESO) published an interim finding from the review into the North Hyde Substation outage.\u00a0<\/p>\n
The report said that the \u201croot cause\u201d of the fire remains unknown, with London Fire Brigade and National Grid Electricity Transmission continuing to conduct forensic investigations.\u00a0\u00a0<\/p>\n\n
The Metropolitan Police Service has previously confirmed that it had \u201cfound no evidence to suggest that the incident was suspicious in nature\u201d.\u00a0<\/p>\n
\nThe report stated that on March 21, 2025, around 12 hours after the fire broke out, power had been restored to all of Heathrow Airport\u2019s terminals and re-energization of the wider Heathrow network was completed by 14:23.\u00a0\u00a0<\/p>\n
\u201cOnce power had been restored, there was a period of safety checking to allow all parties operating the airport to access their systems and to ensure safety critical systems were fully operational prior to passengers arriving at the airport,\u201d said NESO.\u00a0<\/p>\n\n
A small number of flights began operating from the airport again during the early evening of March 21, 2025.\u00a0<\/p>\n
![\"Heathrow](\"https:\/\/www.aerotime.aero\/images\/2025\/03\/Heathrow-Aiport-fire-closure-1200x800.jpg\" "\\"Heathrow")