Difficulties of navigation at night

A key part of accurate bombing was accurate navigation. Forced to fly at night to avoid German fighters and flak, RAF aircrews had to find their way across Europe to their targets in darkness and through frequent cloud and bad weather.

During the early part of the war, the navigator on board each bomber had few aids to help him work out his aircraft’s position. He could only map read if he could see the ground, or use his sextant to navigate if it was clear enough to see the stars. But it was risky to fly straight and level on a clear night for several minutes whilst taking careful measurements from the stars as it made the aircraft an easier target for German night-fighters.

The primary method of navigation at this time was ‘dead reckoning’. The navigator kept a log of the pilot’s instruments indicating their aircraft’s direction and airspeed. Using forecast wind speeds (issued by meteorologists before take-off) in his calculations, he could then work out their position. But often the weather forecasts were incorrect. Unexpected winds could send an aircraft miles off-course and affect its speed over the ground. In order to check where they actually were, the aircrew had to spot a landmark (e.g. a coastal, river or road feature) to accurately fix their position. Then the navigator could calculate the actual wind speed and start the dead reckoning process again.

Navigators were later helped by Air Position Indicators which simplified the calculation of the aircraft’s position based on direction and speed, but the lack of technology to accurately forecast wind remained a problem.

If a bomber was able to reach the target area, the crew then had to identify their specific target (e.g. a factory, railway yards or docks). Often cloud, mist, fog, haze, smoke or industrial pollution made the job almost impossible.

Only if they were lucky enough to get back over Britain could the bombers use visual and radio beacons on the ground to be guided to their airfields – but poor weather, technical breakdown and frequent battle damage to their aircraft often made even this task very difficult.

A lost bomber

On one occasion in May 1940 a disorientated RAF crew flying in poor weather at night bombed what they took to be an enemy airfield in Holland. They later realised to their horror they had actually bombed an RAF fighter base in Cambridgeshire. Fortunately no-one on the ground was hurt and the bomber got home safely. In the typical humour of the time, two Spitfires from the fighter base flew over the errant bomber’s home airfield the next day and dropped mock German Iron Cross medals.

However comic, this incident represented a very serious problem. Unpredictable weather, fog, heavy cloud and lack of navigation equipment meant aircraft were missing their targets and often getting hopelessly lost trying to reach home, with tragic consequences. Bad weather and navigational errors caused many airmen to be killed and many aircraft destroyed.

Fatal training

Training exercises involving inexperienced young aircrews flying older, poorly-equipped aircraft at night was another cause of frequent fatal accidents.

	Night flying
	"You are in a completely strange and alien environment, doing everything entirely by instruments."
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	A tough training
	"The trainee pilot of the crashed Wellington caused the aircraft to swerve….it hit another aircraft and burst into flames."
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The reality of an impossible task

A secret British government survey in the summer of 1941 reported that only 30% of bomber crews were getting their bombs to within 5 miles of the target. A shocked Air Ministry radically reduced bombing operations over the winter to conserve forces. A reassessment of Bomber Command’s operations in the autumn of 1941 would lead the Air Ministry to order the bombers to target industrial areas of German cities rather than try to hit (and probably miss) one specific factory. This tactic was known as ‘area bombing’.

New hope

Scientists had been working tirelessly to develop new compasses and navigation systems but it was not until the spring of the following year (1942) that new technological breakthroughs, together with new aircraft and a new commander-in-chief were to transform Bomber Command’s fortunes.