WWII instrument landing with glide slope indicator?

[Jenisch]

Hello,

I know that by the 1930s at least the German Lorenz Beam system was already used by civil aviation and provided aircraft with the capability of conduct an instrument landing with lateral guidance by a radio aid. However I was wondering if during WWII military aircraft operated a system capable of providing vertical and lateral orientation to an aircraft landing. If not for ordinary single-engine fighters, at least for the bombers and other large aircraft.

Thanks since now for the attention,

Marcelo Jenisch.

 

[FLYBOYJ]

there was an LF system that only told you if you were right or left of the "beam," basically a aural localizer. History of Aircraft Landing Aids

 

[Jenisch]

Hello Flyboy,

Thanks for the link. ^^

Your link says:

"The instrument landing system (ILS) incorporated the best features of both approach lighting and radio beacons with higher frequency transmissions. The ILS painted an electronic picture of the glideslope onto a pilot's cockpit instruments. Tests of the system began in 1929, and the Civil Aeronautics Administration (CAA) authorized installation of the system in 1941 at six locations. The first landing of a scheduled U.S. passenger airliner using ILS was on January 26, 1938, as a Pennsylvania-Central Airlines Boeing 247-D flew from Washington, D.C., to Pittsburgh and landed in a snowstorm using only the ILS system.


More than one type of ILS system was tried. The system eventually adopted consisted of a course indicator (called a localizer) that showed whether the plane was to the left or right of the runway centerline, a glide path or landing beam to show if the plane was above or below the glide slope, and two marker beacons for showing the progress of approach to the landing field. Equipment in the airplane allowed the pilot to receive the information that was sent so he could keep the craft on a perfect flight path to visual contact with the runway. Approach lighting and other visibility equipment are part of the ILS and also aid the pilot in landing. In 2001, the ILS remains basically unchanged.


By 1945, nine CAA systems were operating and 10 additional locations were under construction. Another 50 were being installed for the army. On January 15, 1945, the U.S. Army introduced an ILS with a higher frequency transmitter to reduce static and create straighter courses, called the Army Air Forces Instrument Approach System Signal Set 51. In 1949, the International Civil Aviation Organization (ICAO) adopted this army standard for all member countries. In the 1960s, the first ILS equipment for fully blind landings became possible."

Interesting information. For logistic reasons, I guess that if the ILS was just being introduced on US soil for military operations by 1945, I suppose it was not widely employed outside the country. However I deduce that specially by the last months of the Pacific War it may have started to be implemented with significance

 

[Jenisch]

According to this Wikipedia article:

Instrument landing system - Wikipedia, the free encyclopedia

This:

Is a Luftwaffe AFN 2 indicator, built 1943. It appears to have a glide slope indicator. Anyone knows how the Germans used radio aids for landing operations?

 

[nuuumannn]

This

Radio navigation aids also assisted in landing. One type, introduced in 1929, was the four-course radio range, where the pilot was guided by the strength of Morse code signals. Another type that was tried experimentally was the low-frequency radio beam. These radio beams flared outward from the landing point like a "v," so at the point farthest from the runway, the beams were widely separated and it was easy for the pilot to fly between them. But near the landing point, the space between the beams was extremely narrow, and it was often easy for the pilot to miss the exact centerpoint that he had to hit for landing. Another new method had a pilot tune into a certain frequency at a checkpoint far from the airport, then use a stopwatch to descend at a precise rate to the touchdown area of the runway. This method also proved difficult.



The instrument landing system (ILS) incorporated the best features of both approach lighting and radio beacons with higher frequency transmissions. The ILS painted an electronic picture of the glideslope onto a pilot's cockpit instruments. Tests of the system began in 1929, and the Civil Aeronautics Administration (CAA) authorized installation of the system in 1941 at six locations. The first landing of a scheduled U.S. passenger airliner using ILS was on January 26, 1938, as a Pennsylvania-Central Airlines Boeing 247-D flew from Washington, D.C., to Pittsburgh and landed in a snowstorm using only the ILS system.



More than one type of ILS system was tried. The system eventually adopted consisted of a course indicator (called a localizer) that showed whether the plane was to the left or right of the runway centerline, a glide path or landing beam to show if the plane was above or below the glide slope, and two marker beacons for showing the progress of approach to the landing field. Equipment in the airplane allowed the pilot to receive the information that was sent so he could keep the craft on a perfect flight path to visual contact with the runway. Approach lighting and other visibility equipment are part of the ILS and also aid the pilot in landing. In 2001, the ILS remains basically unchanged.

From here: History of Aircraft Landing Aids

Anyone knows how the Germans used radio aids for landing operations?

Basic information on Lorenz:

Lorenz beam - Wikipedia, the free encyclopedia

The British used this:

Blind approach beacon system - Wikipedia, the free encyclopedia

 

[bobbysocks]

If allied planes had the ability to fly by instruments right down to the ground to their bases....the germans could figure out a way to exploit that. using instruments themselves, when the weather was horrible, they could follow allied the formations home. the weather would prevent them from being distinguished as allied or not. they could bomb the bomb the base and head back to germany where the weather my be a lot clearer. AA isn't going to see them and you are not going to launch fighters in that kind of pea soup. if you bomb a field when everything is landing you could do a massive amount of harm. this may only work once but would force a change in tactics or deployment..

 

[BiffF15]

Bobbysocks,

I'm pretty sure the Allied aircraft used an IFF (Identification Friend or Foe), which helped prevent events like what you described.

Cheers,
Biff

 

[nuuumannn]

If allied planes had the ability to fly by instruments right down to the ground to their bases....the germans could figure out a way to exploit that. using instruments themselves, when the weather was horrible, they could follow allied the formations home. the weather would prevent them from being distinguished as allied or not.

In theory, almost anything is possible, really. Firstly, the British bombers didn't fly in formation home, normally they made their own way back, rather than waste time forming up in groups over enemy territory. The practicalities of such a thing might go against it. Following another aircraft in bad weather, even fitted with a tracking device is not made easy because of the weather; the pilot is concentrating on his instruments; the strain of doing so for long periods of time following an aircraft that is a wavy line on a radar screen would be an extremely taxing thing. And if you can see the enemy bomber ahead, chances are he can see you. Remember that British bombers frequently got lost in bad weather themselves returning from target areas, so how might a German shadower determine he was going to end up over a suitable target area? Also, the chances of the German shadower getting lost itself using the radar equipment of the day to track aircraft would be quite high. Even then, in bad weather, at night, what could an interdictor hope to achieve over a target area, such as an airfield, with buildings spread out all over the place? If visibility is so poor the British couldn't see their attacker, chances are the attacker can't see the ground all to well either.

A better alternative might be to make deliberate attacks on British bomber bases as targets, rather than a risky option of tailing bombers home. I can vaguely remember something about a German fighter following a British bomber home and causing a bit of damage, but a bit of a risk hedging your bets on a campaign of doing so. The German JaBo sorties caused quite a bit of alarm when Fw 190s were sent at high speed and low level over the Channel; this seems to be a more legitimate means of achieving the same aim.

 

[bobbysocks]

all true. like you I do remember a bomber or fighter being followed home but cannot recall all the circumstances.

 

[Airframes]

Luftwaffe night intruders did fly over the UK, in the areas of, or approaches to, known RAF and USAAF airfields.
Quite a number of bombers were lost just as they thought they were safely home, with a notable loss to USAAF night operations in late 1944 - can't remember the date offhand.
The German aircraft did not 'follow the beam' of allied ILS systems of the period, but 'loitered' until a radar 'fix', or visual, was obtained.
However, quite a number of Luftwaffe night losses over the UK were also incurred, both to allied night fighters, and flak.

 

[FLYBOYJ]

According to this Wikipedia article:

Instrument landing system - Wikipedia, the free encyclopedia

This:

Is a Luftwaffe AFN 2 indicator, built 1943. It appears to have a glide slope indicator. Anyone knows how the Germans used radio aids for landing operations?

"FuBL 2 Used the Knickebein beam navigation and bombing system. Consisted of the EBL 3 and EBL 2 receivers with display device ANF 2. The EBL 3 operated between 30 and 33 Mhz and received 34 channels, The EBL 2 operated at 38 Mhz and was unchanged from the FuBL 1 system. The AFN 2 provided the pilot with a left/right display and a signal strength. The unit was available in two versions FuBL 2 H for a unit operated by the radio operator and the FuBL 2 F for remote operation by the pilot in a single seat aircraft.`The primary difference between the EBL 1 and the EBL 3 was sensitivity to allow ,what was basically a ILS system, to be used for bombing."

 

[nuuumannn]

.`The primary difference between the EBL 1 and the EBL 3 was sensitivity to allow ,what was basically a ILS system, to be used for bombing."

Yep, Knickebein was based on Lorenz, the audible dots and dashes working in the same principle over the target area. This is how the British were able to foil its use, by providing a false series of dots and dashes, which led to the Germans thinking they were not over the target area, when in actual fact they were.

Battle of the Beams - Wikipedia, the free encyclopedia

 

[FLYBOYJ]

So with that said, even though that instrument looks like an ILS head, and somewhat operates in a similar manner, it is no where close to an real ILS. A modern ILS is probably 100 times more accurate and what's missing is a published "procedure' on how to use it.

 

[bobbysocks]

Bobbysocks,

I'm pretty sure the Allied aircraft used an IFF (Identification Friend or Foe), which helped prevent events like what you described.

Cheers,
Biff

ya know biff, I am not too sure they did. I don't remember my father alluding to something like that in any of his stories. bill marshall and some of the others would probably be way more knowledgeable on that subject than I. just because he didn't mention it doesn't mean it wasn't in place. but with the sheer number of aircraft in the airspace and the lack of devices like transponders it would be mind boggling. there were 1000+ bomber/600+ fighter raids all coming back over the channel and north sea...that is a lot to track.

I also remember a story about the LWs version of Wrong Way Corrigan who landed his 190 (?) at an allied base thinking he had crossed the channel....but maybe that is more fiction than fact.

 

[Airframes]

Arnim Faber landed his FW190 in England, thinking he had crossed the Channel.
He had - the Bristol Channel !
The RAF were then presented with a brand new, fully functioning 'Wurger' to inspect at leisure.
And yes, in general, all allied aircraft operating over Europe carried IFF, from 1940 onwards.

 

[stona]

I read a late war Bomber Command account in which, due to bad weather, the aircraft of the returning bomber stream were ordered to turn on their navigation lights. The sudden revelation of the close vicinity of so many aircraft scared the teller more than the German flak had done.
He had flown many times in exactly the same situation, but the darkness had kept him in blissful ignorance.

Cheers

Steve

 

[pbehn]

Luftwaffe night intruders did fly over the UK, in the areas of, or approaches to, known RAF and USAAF airfields.
Quite a number of bombers were lost just as they thought they were safely home, with a notable loss to USAAF night operations in late 1944 - can't remember the date offhand.
The German aircraft did not 'follow the beam' of allied ILS systems of the period, but 'loitered' until a radar 'fix', or visual, was obtained.
However, quite a number of Luftwaffe night losses over the UK were also incurred, both to allied night fighters, and flak.

The LW certainly infiltrated the bomber streams returning to Yorkshire, there is a memorial to it at Elvington. From memory a ju88 was shot down and it destroyed a cottage when it crashed. edit...I found this

RAF Elvington - A Brief History - Yorkshire Air Museum

On the night of 3rd March 1945, German night-fighters launched Operation Gisela against the 450 heavy bombers of 4, 5 & 6 Groups RAF Bomber Command returning from a raid on the synthetic oil plants at Kamen, in the Ruhr and the Dortmund Canal. At around midnight 100 Junkers 88's crossed the English coast from the Thames to Yorkshire and infiltrated the returning bomber streams. Two hours later at least 24 bombers had been shot down and a further 20 damaged.
Having shot down two Halifax bombers of 158 Squadron returning to RAF Lissett near Bridlington, Hauptman Johann Dreher of 13 Nachtjagdeschwader Gruppen (Night fighter destroyer group), in his Junkers 88G turned to attack the French Air Force Halifax's landing at Elvington. The runway lights were switched off and all aircraft ordered (in French) to divert to other airfields. It was 1:50am and as the alarms sounded, Capitaine Notelle's Halifax pulled sharply up and, narrowly escaping, headed north towards RAF Croft. He was stalked by another German night fighter and was hit 3 times before crash landing near Darlington. All the crew survived. Meanwhile, Dreher's Junkers 88 continued to attack RAF Elvington, strafing the road and a passing taxi. Circling round for another attack, it clipped a tree and crashed into Dunnington Lodge farmhouse, killing all 5 crew; the farmer, Richard Moll; his wife and mother. A black cross can be seen by the roadside in front of the farmhouse near the Museum on the road back to York. The war ended just 9 weeks later and this is probably the scene of the very last Luftwaffe aircraft crash on British soil.

 

[bobbysocks]

Arnim Faber landed his FW190 in England, thinking he had crossed the Channel.
He had - the Bristol Channel !
The RAF were then presented with a brand new, fully functioning 'Wurger' to inspect at leisure.
And yes, in general, all allied aircraft operating over Europe carried IFF, from 1940 onwards.

yes that is the fellow....thanks.

Do you have any more info on the IFF system or protocols they used???

 

[Jenisch]

I'm bringing this back to life because I found an interesting link with a text about radar approach in WWII by some of the folks involved with the subject: http://www.rquirk.com/cdnradar/cor/chapter21.pdf

For those who read the text: is that system essentially the same as the precision approach radar (PAR) still used today?

 

[davparlr]

I'm a bit confused. Radio direction finders were certainly in use very early and could have provided lateral approach data to a two man crew to non-precision minimums, although the two man system using a manual direction finder might prove interesting. however, automatic direction finding (ADF) would simplify non-precision approached considerably. I could not find when the first ADF was utilized. It is, however, probably still used somewhere today. It certainly was in the early 70's (I can't believe that was 40+ years ago) in Ethiopia and Iran (which had a interesting four ADF approach, luckily our plane had four ADF heads so I just switched between heads on fly-over). I never flew one to non-precision altitudes as Addis Abba was VFR and Tehran was to an ILS final. As an interesting side note, I did fly an A-N range in Canada once but it was just for fun in that we had VOR. Back to the original question, I don't know when standard use of glide slope was used, nor when precision ground controlled radar was used but it was certainly used during the Berlin airlift.