Two military planes came within 30ft of a head-on collision over the North in an incident that has re-ignited fears over the safety of RAF low flying.
A trainee air force pilot turned while on manoeuvres north of Alnwick, in Northumberland, only for an RAF Tornado to pass directly beneath him at a height of just 250 feet.
An investigation into the incident revealed that the two air force planes - which were on separate operations - had no idea about each other's presence.
The inquiry rated it as the most serious type of near miss - a class A Airprox where there was a real risk of collision.
As the two planes headed towards each other at a combined speed of 875mph (760 knots), the collision avoidance system fitted to one of the aircraft failed to work.
The official report into what happened says simply: "In this case, luck prevailed".
The incident is the latest in a long line of crashes and near-misses over the North-East involving RAF planes.
Last night Berwick MP Alan Beith, in whose constituency the incident occurred, said: "This type of incident should not happen. It clearly suggests yet again failings in the management of the low flying programme.
"It is very fortunate that this was not fatal for all the air crew involved."
The RAF uses the airspace over the North-East countryside for a lot of its training because of its sparse population and the presence of a number of military bases it can use as targets for pilots in training.
But the growth of passenger aircraft from the region's airports has led to worries about conflict with civilian planes.
In uncontrolled airspace - zones where air traffic controllers do not track aircraft - pilots avoid collisions simply by looking out for each other in what is called the "see and avoid" principle.
Some planes also have collision avoidance systems fitted, but the equipment on the Tucano plane being used by the trainee pilot did not work in this case, probably because of the terrain in the area.
The report by the UK Airprox Board - which investigates reports of near misses in British airspace - has just been released into the incident in November.
It says: "Patently `see and avoid' had not worked during this encounter at low level where the closing speed of about 760 knots clearly gave the crews little opportunity to spot each other's aircraft in time to take appropriate action.
"Both crews were to varying extents somewhat distracted at the critical moment, it would appear."
A Ministry of Defence spokesman said last night: "We are very aware of the risks associated with flying and flight safety remains a high priority. We study the lessons learned from the Airprox reports and, where appropriate, take action to minimise the risk."