AIRLINE pilots are calling for tests to be carried out to discover what would happen if a drone hit a passenger jet, amid a recent spate of near misses.

The British Airline Pilots Association (Balpa) wants the Department for Transport and the Civil Aviation Authority (CAA) to back research into the possible consequences of such a collision.

It comes after a drone came within two wing lengths of a BE200 aircraft as it was coming in to land at Southampton Airport last July.

Investigators found that ''chance had played a major part'' in a collision being avoided. Most planes landing at Southampton fly across parts of the Winchester districts including villages such as Twyford and Colden Common.

Former RAF and British Airways pilot Steve Landells today warned that a drone hitting an airliner could result in an uncontrolled engine failure or a smashed cockpit windscreen.

Some 23 near misses between aircraft and drones were investigated by the UK Airprox Board (UKAB) in just six months according to its latest reports, including 12 given an A rating - meaning there was ''a serious risk of collision''.

Mr Landells, Balpa's flight safety specialist, said there is a large amount of data on the effects of bird strikes on planes, but he insisted that this is not a true representation of what would happen with a drone because ''birds don't have a big lump of lithium battery in them''.

He told the Press Association it is ''very likely'' that the battery of a standard quadcopter drone entering the core of a jet engine would cause an uncontained engine failure, as happened to a BA plane which became engulfed in flames and smoke as it was taking off in Las Vegas in September.

''You end up with very high velocity bits of metal going anywhere they like. That could be through fuel tanks, through hydraulic lines and even into the cabin,'' he said.

''Losing the engine is not going to cause an aircraft to crash because they are designed to fly with one engine down.

''But an uncontained engine failure is going to be different every time. That could be very serious indeed.''

Mr Landells explained that he wants testing with drones to be carried out because it appears none has been done before.

''The first thing we want to do is get a drone or at least the critical parts of a drone flying at a windscreen of an aircraft,'' he said.

''The indications so far with computer modelling are that you'll end up with penetration of a windscreen.

''One possibility is that the battery smashes the windscreen and the inside layer of the windscreen shatters and you end up with a lot of glass in the cockpit, probably moving at quite high speed. As a pilot, I don't want to be sitting there when that's going on.''

He added: ''There's also a possibility that it might just bounce off. We don't know at the moment.''

Mr Landells said the initial tests could cost around £250,000.

Philippa Oldham, head of transport and manufacturing at the Institution of Mechanical Engineers, described the consequences of a drone hitting an airliner as ''such an unknown thing'' that would depend on a number of factors such as the size and speed of the drone and the location of the collision.

''There's a lot of scenario planning going on around that at the moment,'' she said.

''The impact potentially could be anything from nothing to a destruction of an engine.''

People who fly drones close to planes could be convicted of endangering the safety of an aircraft which has a maximum prison sentence of five years, the CAA said.

A spokesman for the regulator urged drone users to understand that the UK has ''one of the busiest areas of airspace in the world'', featuring passengers jets, military planes, helicopters and gliders.

He added: ''They must be aware of the rules and regulations for flying drones that are designed to keep all air users safe.''