BOEING FLYING FORTRESS I-101C PILOT LOCALISER / GLIDE PATH INDICATOR

As if running the gauntlet Luftwaffe fighters hell bent on blasting you out of the air; layers of deadly enemy flak rising up to greet you and the ever present danger of midair collision with other aircraft in your tightly grouped bomber box wasn't enough, many bombers (often damaged) were returning to their home airfields shrouded in thick fog or deluged in blinding rain.

In fact, landing crashes due to adverse weather was a constant issue for both the RAF and USAAF operating from the muddy runways of England.

Known as the ‘Blind Approach’ or ‘Instrument Landing’ pilots of modern day aircraft are assisted by an overwhelming array of computerised/radar assisted instrumentation and automated landing systems. In fact, most modern civilian commercial airliners can be landed from the airfield tower by remote. 

Unfortunately this was not the case for WWII bomber pilots, often wrestling with damaged aircraft and disabled crew, returning to their fields in darkness, thick fog or driving rain had to face.  

RAF losses to fog and other adverse weather conditions would often outstrip any losses due to enemy action. This was never more disastrously demonstrated than on the night of 16th - 17th December 1943 - the RAF’s infamous, ’Black Thursday’.

Returning from a night time raid on Berlin, Bomber Commands original force of 483 Lancasters and 15 Mosquitoes had suffered some significant losses from anti aircraft fire and Luftwaffe night fighters which had downed 25 of the Lancaster fleet near or over the target area. Unfortunately, these losses were nothing to what awaited the surviving aircraft upon their return.

What had been a light mist over much of southern England on takeoff, had turned into a thick blanket of fog by the time of their return. With visibility dropping by the minute, command centres were pushed to their limit as they tried to divert the returning fleet to alternative airfields.

Technical aids for landing assistance were still in their infancy with only three basic systems available to the pilots. One, GEE was a radio navigational aid which transmitted a homing signal to the aircraft’s Marconi R1155 Radio Receiver’s directional finding antenna which would then display a visual aid to the pilot via the Left/Right Beam Approach Indicator.  

The two floating cross-hair needles of the L/R Indicator provided the pilot with a visual indicator of the aircraft’s position in relation to the airfields radio transmission, directing him to turn either left or right to stay on course.

Unfortunately, GEE could only guide the aircraft back to the airfield. It could do nothing to assist with landing safely in the dead of night, on a runway shrouded in fog. From that point the pilot relied on his Standard Beam Approach Indicator which emitted a combination of flashing lights and audio buzzes to help him align with the runway.

The USAAF and US Navy used a similar system in their bombers known as the Modified A-1 Runway Localiser System which was used in conjunction with the aircraft's radio bearing Indicator and guided the pilot along the correct course and glide path for landing in conditions of poor visibility.

As the aircraft approached, a series of runway-based transmitters broadcasted narrow beam signals which were interpreted by the onboard A-1 Runway Localiser System and displayed on the Pilot Localiser / Glide Path Indicator mounted on the aircraft’s main flying panel.

If the aircraft was approaching along the centreline of the runway, the vertical needle would appear centred on the indicator’s vertical centreline. If the aircraft was right of the runway, the vertical needle would appear to the left of the centreline, and vice versa.

If the aircraft was approaching the runway on the correct glide path, the horizontal needle would align with the indicator’s horizontal centreline. If the aircraft was angled above the correct glide path (in which case the aircraft would overshoot the runway), the right end of the horizontal needle would angle downward, directing the pilot to increase the angle of descent.

If the aircraft was angled below the correct glide path (which would cause the aircraft to land short of the runway), the right end of the horizontal needle would angle upwards, directing the pilot to decrease the angle of descent. (Thanks to Aeroantique.com for the Localiser operational description).

The Westinghouse 1-101C Pilot Localiser/Glide Path Indicator was installed at the top left fo the B-17 Main Flying Panel. This example was installed in early 1943 and bears a re-service date of October 1944 on the rear of its casing. 

For a WWII B-17 cockpit instrument, now well over 75 years old, this instrument is in remarkable condition with a relatively unmarked casing and glass face. 

The Pilot Localiser Unit’s service tags and labels show it as an operational instrument that has been removed from an operational aircraft and would make a fantastic and totally unique and treasured, original aircraft collectable gift from a bygone era of one of the world’s most iconic USAAF bombers.

This B-17 Flying Fortress Instrument comes complete with detailed Scale Model, Mango Wood Stand & Plaque plus Printed Fact Sheet featuring photo of instrument in aircraft cockpit.

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