Forum: F-16 Armament & Stores

Active Member Joined: Nov 29, 2004 - 01:40 PM Posts: 146

A question was asked in another thread about why the F-16 isn't allowed to fire its gun.

First, I want to say that you can get all of the performance info you need about it from the M61A1 info section of this website.

Roscoe and others correctly pointed out that the F-16 does fire its gun, just not on a regular basis.

Look at it this way, how much maintenance do you perform on your 9mm personal handgun or hunting rifle after each time you take it out and actually shoot it? Now lets multiply it by one thousand (I am quite serious here).

If the gun only fires a few rounds (less than half), no major maintenance is needed, just a visual check to ensure everything is still where it should be.

Every one thousand rounds fired requires a barrel erosion check, to see how far down the rifling has worn in each barrel. There is a nifty little projectile shaped guage that tells us if all is well or not. This check must also be performed if an entire load of ammo is fired off in 30 seconds or less. I don't know why they chose 30 seconds, but thats why those guys are the engineers and not me Whistle

Every 15k rounds, a complete tear down is required. Same at 30k. I think there are interim checks as well, but its been over a year since I last worked in an Armament Flight.

Anyhow, a complete teardown is a very involved process. It involves the NDI (Non-Destructive Inspection) section from Fabrication Flight to do some x-rays on certain pieces, and a good scrubbing of all the parts.

The good news, is that most arm shops have a parts washer that will do this for you, but if you have to do it by hand, its simple-green a wire brush, your own two hands and some rags, which takes forever.

After the cleaning, the gun, and its ammunition handling set are put back together, and ops checked. During all of this, inspections of each part are being performed, to make sure they are good to go, and replaced as needed. Some parts are required to be replaced at each overhaul, and some will last the lifetime of the gun. I should also mention, that the ops check only checks the mechanical assembly, and does not actually fire any rounds.

Then its time for our good friends QA to come on down and fail us because we are not worthy. Slap

(Just kidding) (Off Topic) Actually the QA guys are usually really cool, and are there to help you do your job better. It just seems like they are the enemy when I am at the Group Commander's monthly QA review meeting, and my flight is getting beat up for QA violations. (Back on topic)

I should also mention that this must be accomplished within 72 hours from receiving the gun from the flight line. This usually means that it will take all 72 hours to accomplish, and that the guys working on it will be working on it for their full shift, and that will be two, and sometimes three crews working to make it all work out just right.

The typical gun system overhaul is an expensive thing. I would have to go look it up in fed-log if I could remember all the parts, but as I recall, the cost was over $5000, and thats if nothing major broke.

Something else to keep in mind is that the gun is scheduled to be serviced once every 18 months. This will happen regardless of if the gun has fired or not. However, if the gun does fire enough rounds to require an overhaul, then its 18 months starts over again when the inspection is completed. The other bit of all of this is that the jet cannot fly without the gun installed.

To answer the other question about the depot, no there is nothing that they can do to fix this. There were about 10 TCTO (Time Change/Compliance Technical Orders) that came out in the year that I was in the Armament Back Shop. These were various little upgrades, or retrofits to the gun system, and I promise you many more have since come out. There is nothing that a depot could possibly do to upgrade the M61A1 to be able to fire on a more regular basis without significant maintenance.

This gun system has been around since 1947. Granted, that was a very basic version, but the overall system remains unchanged. Every US fighter since the last of the .50-caliber guns went away has had an M-61 in it.

Armament troops, please feel free to jump in here, and fill in any holes or down right inaccuracies here. Thanks!

Now its time for Guiness

, at least as soon as I get home tonight from my shift.

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Well done! Salute

AmmoCapt,

Thanks for all the great info Smile

! I never knew that much work had to be done Shocked

!!!

I just have one question - why can't the jet fly without the gun installed? I know the T-Birds yank the guns in their jets to make room for the smoke system. Is it due to weight and balance concerns or is it just a good idea to make sure the jet can deal with an airborne threat (terrorists) if the need arises in its area of operations?

Thanks again and have fun!

It is a weight and balance concern. The T-Birds fly with an oil drum in place of the gun to simulate the weight. As a crew chief, we have to make sure that the gun is installed before letting the jet go back on status.

Thanks for the confirmation Vipercr8z Smile

! I kinda figured it was something like that.

Parrothead, it was the same deal with Recon Rhinos. If a bird was going to fly without cameras, then they had to put ballast in the camera bay to compensate.

Beers and MiGs were made to be pounded!

Contrary to popular belief, you can fly an F-16 without the gun system. Don't believe me? Check out four jets in the 46th Test Wing at Eglin; 90-0949/0950/0951, and 92-0405. They're all block 15's (49/50/51 are B's, 405 is an A) and all have the guns removed. As of the summer of 2004, none had anything installed in their place. 405 was especially enjoyed by the pilots, but all four were enjoyed for their BFM/ACM prowess-thanks to their CG being more aft than usual, the only thing on base that could turn with them was the test wings UH-1.

Now, why were the guns removed? Those four jets spent 10 years at AMARC before they were genned back up and given to us; the story we heard was the AF needed guns, so they were pulled, and an engineers disposition was given to fly the jets without the gun system and without any sort of ballast in their place. I would say it was a test thing too, but when I left Eglin those four jets had a minimum of test equipment installed (I think only one or two of the B models had anything at all).

Contrary to popular belief, you can fly an F-16 without the gun system. Don't believe me? Check out four jets in the 46th Test Wing at Eglin; 90-0949/0950/0951, and 92-0405. They're all block 15's (49/50/51 are B's, 405 is an A) and all have the guns removed. As of the summer of 2004, none had anything installed in their place. 405 was especially enjoyed by the pilots, but all four were enjoyed for their BFM/ACM prowess-thanks to their CG being more aft than usual, the only thing on base that could turn with them was the test wings UH-1.

Now, why were the guns removed? Those four jets spent 10 years at AMARC before they were genned back up and given to us; the story we heard was the AF needed guns, so they were pulled, and an engineers disposition was given to fly the jets without the gun system and without any sort of ballast in their place. I would say it was a test thing too, but when I left Eglin those four jets had a minimum of test equipment installed (I think only one or two of the B models had anything at all).

VPRGUY,

Good Info but you lost me when you listed the tail numbers. Wouldn't 90-0949/0950/0951, and 92-0405 make these jets at least Block 50's and not Block 15's as you stated? I thought that the last Block 15's had tail numbers that started with 82- and 83-

Those birds were some of the group of As and Bs that were destined for the Pakistani AF, but were embargoed. They are indeed Blk. 15s. They were being produced at the same time Blk. 40s were rolling off of the line.

Beers and MiGs were made to be pounded!

Good catch B25CC, you are right with the normal tail number sequencing. TC, however, is right in this one: The jets were set to go to the Pakistani AF, and were manufactured in the early 90's. I believe there were 20-30 jets total in that package. For whatever reason the US government decided to keep the airplanes, so they were sent to AMARC. When the aircraft were regenerated, most went to the Navy to augment their aggressor squadrons (so yes, we've got Navy boys flying F-16's!) We got four of them at the test wing, to augment our photo ship fleet- that is why three of them are busses. The single seat A model (405, my second airplane) was designated as the 46TW Flagship, since the Wing CC (Nolan at the time) liked the older airplanes.

All four were decked out with some updated avionics, and possibly most importantly, PW 220 engines instead of the regular 200's. That is what made them such favorites with the pilots: block 15 simplicity and weight, with updated gizmos and block 40 power, combined with that aft CG from the gun removal. That made for great acceleration and power, with an astounding pitch rate- perfect for WVR ACM. Maybe they were being nice and trying to butter up the poor crew chief (me), but most pilots claimed 405 was the best (and most fun) dogfighting jet we had because of all that.

That makes sense. I didn't know what tail numbers the imbargoed Pakistani jets were. I do remember that most of them ended up going to the navy for aggressor training (DACT). You are correct that the 220E is a nice engine (ok all you GE guys can throw stones now). When I first came into the AF, I worked the Block 25's just as they were being delivered to USAFE with the PW-200. What a POS motor. My jet spent more time on the trim pad hooked up to AGETS getting adjusted than it did in the air. At least once a week, BANG.....AB Blow out. That 220E motor is sweet compared to what I came off of.

There were 28 embargoed Block 15 OCU's destined for Pakistan that ended up getting split evenly between the Navy and Air Force. The Navy has all 14 at Fallon. An interesting note about their gun is that it is installed but they NEVER fire it.

Pete

Most likely because of all those TCTO's that would have to be done! Why bother, when an A/A aggressor isn't going to use the gun at all anyway?

Yeah - you're just going to say, "Guns, guns, guns" and then look at the HUD tapes in debrief. BTW - other reasons not to fire the gun regularly is that the gas causes corrosion and it makes the jet look crappy from all the smoke that builds up aft of the gun port. (Also it disturbs the birds who have built nests in there)

Forum: F-16 Armament & Stores

F-16 and the M61A1