This artical was in the Observer Newspaper the following Sunday.
At 6.30 a.m. on 15 November 1986 the London Air Traffic Control Centre (LATCC) at West Drayton suffered a total loss of mains power as the morning rush of flights began. A standby generator also failed. Radar screens covering Wales and England south of Newcastle went blank. The IBM 9020 computer shut down, halting updating of flight progress strips. Controllers had to revert to writing strips manually.
Radio contact with aircraft was precariously maintained by a battery supply with a life of 30 minutes. Pilots continued to fly in the busy airspace without radar by scrupulously maintaining their separation from other planes. But without radar monitoring by controllers on the ground little could have been done if a jet had strayed.
Power was restored five minutes before the batteries gave out. The fault was blamed on a freak sequence of events started by the failure of a small capacitor.
Managers were eager to clear the backlog of flights but the computer would not function normally. It displayed some radar returns but not others.
A LATCC controller said: 'We were pushed to handle more aircraft but refused because the computer could have gone down at any time. We were lucky. If the same sequence of events occurs in the summer, the effect does not bear thinking about.'