An RAF fighter pilot left "little margin for error" after a near-miss with a microlight that was coming in to land, according to an air safety report.
The Tornado was flying at low level at about 483mph on the Nottinghamshire and Lincolnshire border near Headon airfield when it passed 300ft beneath the "startled" microlight pilot.
In a report by Airprox, which looks into all such incidents, investigators also heard that military maps were also being redrawn after it emerged the site of the civilian airfield in Nottinghamshire was marked in the wrong spot - by half a mile.
While the warplane's male pilot was "entitled to fly where he had", the board of inquiry concluded a wiser course of action would have left more room for manoeuvre.
It also emerged that the pilot of the multimillion-pound Tornado, packed with state-of-the-art navigation kit, failed to spot the smaller aircraft as he passed 500ft above the ground.
The near-miss only emerged after the microlight pilot flagged the incident to the authorities, once safely back on the ground.
Airprox concluded the incident on October 2, last year, was a "Category A", meaning "a serious risk of collision has existed".
The report stated: "The Tornado pilot would probably have been better placed to have remained at height until further north due to the myriad of small airfields and avoidances in that particular area.
"Essentially, the Tornado pilot was threading the gap very finely between these airfields and, although his planned routing would have taken him clear of Headon airfield had it been marked on the charts correctly, he had left very little margin for error and would have been wiser to have allowed himself much more room to manoeuvre."
The investigating board said they were "heartened" to hear "military charts were being amended to place Headon in the correct position, and a full quality assurance review of all other entries were being undertaken".
It also recommended the use of transponders - which can communicate with other aircraft - to light aircraft pilots, after it emerged the microlight was not equipped with such a device.
Airprox said: "The board quickly agreed that it was a non-sighting by the Tornado pilot and effectively a non-sighting by the microlight pilot that had led to the incident.
"Given the likely high closure rate, and the fact that the microlight pilot assessed that the Tornado flew just 300ft or so beneath him, when assessing the risk the board thought that chance had played a major part and that this was a Category A event."