IFF Question

[kitnut617]

I think you're missing something, during WWII, to get the 'shot', you had to see what you were shooting at, physically no matter what, because usually you had to get within 300-500 yards to do it.  There was none of this 'beyond visual range' stuff then, even the nightfighter pilots had to identify what they were about to shoot at before they shot.

If I recall, there was a case where a C-54 got shot down because it resembled a Fw Condor/Kurier.  If I recall the attack was carried out because of a lack of functioning IFF gear...

Do you recall who was doing the shooting and what date was that

[KJ_Lesnick]

Spring 1944

[Hobbes]

IFF doesn't "identify bad guys": it tells that the bogey is one of your own.
With large bombers coming in toward the UK it would have been a fair bet that they're not our own - and thus legitimate targets.
In Vietnam the requirement was for a positive identification - a fighter-sized aircraft could have been a US one lost or on some mission that the relevant fighter wasn't aware of/ privy to.

Edit for expansion: a POSITIVE response from an IFF says "I'm on your side".
No response says "I'm not on your side" OR "I am on your side but my IFF isn't working".
So far as I'm aware that's the only possible signals you get: no one transmits "I'm not on your side I'm a bad guy".

Not entirely. The IFF transmitter sends a code, "I'm aircraft 35tghtt5b4b46ji8" (or something in that vein). The receiver compares this to a list of known codes.
Now this code would have been something complex as shown above. Sending "I'm Tornado ZJ123 of XY Sqn" would be a security risk, because it gives away information to the enemy. If they can decode the IFF signal, they know exactly who's coming. So the IFF codes are long strings of garbage that are replaced regularly. 

If you receive an unknown code, there are several possibilities:

• possible bogey
• wrong setting on the transmitter
• garbled transmission (miss one character due to static or radio jamming...)
• a not-up-to-date list

At some point, it was found that UK (or US? I don't remember the story exactly) aircraft could receive Soviet IFF codes, the systems were similar enough. So the British interceptor would interrogate the IFF of an unknown inbound aircraft, and get a readable response. But that didn't help much: it would move the aircraft from 'completely unknown' to 'transmitting an unknown IFF code'. You'd still have to make certain it was a Soviet aircraft by other means before taking a shot.

[tahsin]

Source for this "rebellion" please?

I imagine the F-105 crews wanted sidewinders to deal with MiG's, not friendly Phantoms...

Also not sure of the time frame of your Sparrow cite.  There were some 50+ Sparrow kills in the conflict.  Yes numerous misses due to duds, firing outside the envelope etc. and by all accounts had a dissapointing % rate with over 600 fired.  Not sure what you mean by "final tally"?  

I won't bite on the rest of your post.    

The time in question must be just before the Ault Report. Top Gun by -I believe- Tony Holmes should be source of the 45 shootings, but I don't think I will be able to locate my copy. What's not in Tony Holmes book and I think in any book that a least a couple of those shootings were across the Vietnamese-Chinese border. Creating even more problems as "the F-105 drivers on tables shouting for 'Winders" is from a guy who used to know people to trade insults. The people in question had driven things in Takhli and were not exactly fans of the "command" in 65-66. Broughton, I believe. Explicitly for a reason about why Takhli always seemed to get the worst in EW pods.

For the rest of the post? This is not the real deal... More properly attuned guys would be alot more along the line of what follows. A Jordanian F-16 is down in Syria. Just days after the THK commander was on TV flying backseat to the guy who flies the Soloturk. Proves the Turkish Air Force is a mighty weapon of war? Possibly, considering the amount of cowards in Turkey who just froze when the Syrians got that F-4. The cowards are just re-freezing! The question that would be how the Iranians managed to "splash" that thing, into some lake so that the only trophy ISIL gets is a couple of speedbrakes. Left or port, I can't tell. So what's the extent of the IFF library that got compromised? The answer would be only as much as the SA-8 that got provided to ISIL -and not by Turks...

Or an even better one. Now that the Russians are once again threatening to use nukes, possibly inspired by a thing that happened twice, both in the middle of the month... And one of more properly attuned types would certainly be implying the Russian belief that NASA's Curiosity mission provides a convenient cover is a thing that's entirely wrong and there will be but a slap on the wrist.

This is not the real deal, just an over curious poster.

[overscan]

IFF doesn't "identify bad guys": it tells that the bogey is one of your own.
With large bombers coming in toward the UK it would have been a fair bet that they're not our own - and thus legitimate targets.
In Vietnam the requirement was for a positive identification - a fighter-sized aircraft could have been a US one lost or on some mission that the relevant fighter wasn't aware of/ privy to.

Edit for expansion: a POSITIVE response from an IFF says "I'm on your side".
No response says "I'm not on your side" OR "I am on your side but my IFF isn't working".
So far as I'm aware that's the only possible signals you get: no one transmits "I'm not on your side I'm a bad guy".

Not entirely. The IFF transmitter sends a code, "I'm aircraft 35tghtt5b4b46ji8" (or something in that vein). The receiver compares this to a list of known codes.
Now this code would have been something complex as shown above. Sending "I'm Tornado ZJ123 of XY Sqn" would be a security risk, because it gives away information to the enemy. If they can decode the IFF signal, they know exactly who's coming. So the IFF codes are long strings of garbage that are replaced regularly. 

If you receive an unknown code, there are several possibilities:

• possible bogey
• wrong setting on the transmitter
• garbled transmission (miss one character due to static or radio jamming...)
• a not-up-to-date list

At some point, it was found that UK (or US? I don't remember the story exactly) aircraft could receive Soviet IFF codes, the systems were similar enough. So the British interceptor would interrogate the IFF of an unknown inbound aircraft, and get a readable response. But that didn't help much: it would move the aircraft from 'completely unknown' to 'transmitting an unknown IFF code'. You'd still have to make certain it was a Soviet aircraft by other means before taking a shot.

This is not quite correct.

IFF is a system to identify whether a target is friendly. This is done by an interrogator on the ground or in a plane sending out a coded signal, which a friendly aircraft receives, processes, and sends a reply to.

Lack of a response to an IFF system doesn't indicate a hostile target. The  target's IFF could be broken, turned off. Therefore lack of a friendly IFF response is not a confirmation a target is hostile. By design, an IFF system should not answer except to friendly requests.

However, the antennas used for IFF replies are not very directional and the transmissions are quite long range. This has the major consequence of potential of the reply getting snooped by someone. You don't need to be able to decode it to determine whch direction it came from, and if the contents and frequency match a known IFF system, you can easily get a direction and an probable ID.

This is what was exploited by COMBAT TREE and similar US systems, developed after Soviet IFF systems were recovered and compromised. COMBAT TREE was able to receive an IFF reply from a MIG, triggered e.g. by a SAM site, and process it to reveal the direction (and later, a rough distance) to the aircraft, often at greater distances than the radar could detect the aircraft. It would also be guaranteed to be hostile as the signal was distinct from a US IFF response. This was the passive mode.

They also had an even better capability. As the US had broken the Soviet IFF system, the COMBAT TREE equipment was able to send an interrogation signal to the MiG, whose transponder would see it as a genuine request, and ,reply with an "I'm aircraft 21" reply. The reply included details such as the current altitude of the MiG - useful to the MiG's GCI controller, but also to the US Phantom pilot.

North Vietnamese pilots eventually realised what was happening and often kept their IFF turned off except at defined points in the intercept or when in SAM range.

The Soviets were able to upgrade their IFF systems to prevent the original active exploit, and the passive one became less useful when radar range increased and other techniques for target ID were developed. None are foolproof however. It is possible that later systems such as PAROL were broken, but also the later systems also had to remain backward compatible to some extent so that old equipment could get an ID.

Typically, an F-15 pilot would use onboard IFF, onboard radar NCTR, and AWACS ID (probably a combination of IFF and NCTR). If they all agree its hostile, the chances are it is hostile, even if no one system is infallible.

[tahsin]

Just out of curiosity, what's current declared "effect" of Combat Tree, twice the range of the radar set on an average F-4D or three times?

[Go4fun]

It always breaks down to the good old Mark I Mod 0 eyeball. The Redeye system pictured above was called "The Revenger" by the troops because you had to aim at the hot exhaust of the plane meaning he had already made his run at you.

[tahsin]

America in Vietnam, fully confident that its high tech will prevail. Problems, problems and many Sparrow shoots, nothing works. Finally a perfect day, cleared on the IFF as well and two kills... Turns out out to be 2 F-105s with the IFF issues. F-105 pilots start a rebellion to demand Sidewinders to fire on the Phantoms and the final tally of the time: 45 Sparrows fired, 2 own goals, 43 misses. America is well served by those tiny minority who must be obsessed about things.

Source for this "rebellion" please?

I imagine the F-105 crews wanted sidewinders to deal with MiG's, not friendly Phantoms.  Although most of the F-105 MiG kills over Vietnam were with cannon, here is just one source indicating that F-105 pilots believed more kills could have been made had they been equipped with sidewinders earlier and more often.  Page 14

https://books.google.com/books?id=2jJfBAAAQBAJ&pg=PA62&lpg=PA62&dq=f-105+sidewinder+vietnam&source=bl&ots=JR6h08NLOA&sig=ZyXy3pImF4OrzMRycG7H7e0oeok&hl=en&sa=X&ei=ZlShVIrTHsGaNtKrgaAE&ved=0CDkQ6AEwBg#v=onepage&q=f-105%20sidewinder%20vietnam&f=false

Also not sure of the time frame of your Sparrow cite.  There were some 50+ Sparrow kills in the conflict.  Yes numerous misses due to duds, firing outside the envelope etc. and by all accounts had a dissapointing % rate with over 600 fired.  Not sure what you mean by "final tally"? 

...

It's still within 5 years of the last post! Give or take a day or two...

"On the morning of May 7, 1968, five F-4s from the carrier Enterprise engaged two MiG-21s from North Vietnam. According to documents, the F-4s were only able to shoot two Sparrows at the MiGs, neither of which hit its target. One of the Phantoms, crewed by VF-92 members, W. M. Christensen and W. A. Kramer, was shot down by the outnumbered MiGs (though Christensen and Kramer ejected and were recovered).

The engagement occurred at the start of what was to become known as the "America Debacle," a series of dogfights in spring-summer involving F-4s. Two Phantoms would be shot down and over thirty Sparrows fired with only a single MiG kill. Information about the engagements is sparse, but the following can be pieced together.

On May 9, 1968, two days after the VF-92 encounter, two more Enterprise Fhantoms engaged three MiG-21s. Altogether they fired four Sparrows at them, and claimed one "probable" and one "possible" kill, neither kill was officially counted.

A little over a month later, on June 14, 1968, two America F-4s,call-sign "Root Beer," shot four Sparrows at two MiG-17s without a hit. Fifty hours later, two America F-4s ran into two more MiG-21s, and shot four Sparrows, again without a hit. Again, one of the Phantoms was shot down. CMDR W. E. Wilber and his RIO LTJG B. F. Rupinski, both of VF-102, ejected. Wilber became a POW and Rupinski was listed at "KIA" (killed in action).

In all, fourteen Sparrows had been fired at a cost of over $150,000 apiece in a little over one month. In addition, two $4 million Navy airplanes had been destroyed, not to mention the loss of the aircrew. Yet the Navy had not a single kill to show for it.

Three more times that month, F-4s from America and Enterprise ran into MiGs; they shot a total of thirteen more Sparrows and didn't get a hit.

While the F-8s continued to do reasonably well in battle, primarily with the tail-shot Sidewinder, it wasn't until July 10, 1968, that Roy Cash, Jr., and Joseph Edward Kain, Jr., VF-33 crewmembers from America, finally got a MiG in an F-4. They got it with a Sidewinder. The kill only upped the Phantom kill ratio to ten MiGs for five U. S. Navy planes, an overall F-4 kill ratio of a flat 2 to 1. Clearly, the Navy's frontline air combat weapon—plane, crew, and missile—was in trouble. In previous wars, the Navy's kill ratio had been five to eight times higher.

The low point came on August 17, 1968. In a dogfight with two MiG-21s, an F-4 from the Constellation mistakenly hit its own wingman with a Sidewinder, causing a fire. Its crew had to eject, and they became POWs.

In the words of LCDR Jeffrey P. Simpson, writing about the engagements in the winter 1983 edition of The Hook, a magazine devoted to carrier aviation, "It was apparent that something was desperately wrong.""

Thus starts Chapter 11 of "Scream of Eagles - The Creation of Top Gun and the U.S. Air Victory in Vietnam", a 1990 book.

People would be able to see how it could have climbed to 40 plus with two own goals. Though it's hard to see how it should have become a debacle of USS America alone. Unless its fighter units were designated for cross border operations into China. About 10 Sparrows fired at Chinese fighters after they were tracked by the Air Defence cruiser in the area and more destroyers, from the airbases they took off. And it matches Constellation becoming the "fighter carrier" for 1972 with VF-96 "Fighting" Falcons firing all available Sidewinders in training exercises, causing a little crisis of sorts in the West Coast squadrons which had none to fire for the rest of the year? 

This leaves the F-105 incidents to happen at about April/May 1967.