Boeing F-15EX / F-15QA and related variants

[Sferrin]

The Air Force isn't buying the quad packs so it's what 8 missiles on the F-15EX vs. 6 on the F-35 Block 4 in combat trim?

It's up to 16 missiles without the amber racks.
12 missiles with underwing fuel tanks.

8 F-15Xs For USAF And 22 F-5s For Navy In 2020 Budget Request

The F-15X is officially real and the Navy and Marines are set to get a fresh influx of badly needed aggressor airframes.

www.thedrive.com

And when the Air Force ANG units actually fly regularly with that configuration let me know.

I'll bet they do that sooner than F-35s will fly with 6 AIM-120s internally.

A beer of your choice <= $50. Lot 15 arrives in CY2023...same time at F-15EX IOC.

Except technically it's already flying in that configuration in the form of the F-15SA, QA, etc. 6 AIM-120s internally on an F-35 is still a powerpoint.

 

[TomcatViP]

@marauder2048 : if I may suggest:

 

[Jeb]

Question about aggressor squadrons in the US
since the US has the money and network to acquire actual Soviet/Russian types, maybe even Chinese types
could they build an aggressor squadron using actual aggressor aircraft?

Who's to say they haven't?

 

[marauder2048]

The Air Force isn't buying the quad packs so it's what 8 missiles on the F-15EX vs. 6 on the F-35 Block 4 in combat trim?

It's up to 16 missiles without the amber racks.
12 missiles with underwing fuel tanks.

8 F-15Xs For USAF And 22 F-5s For Navy In 2020 Budget Request

The F-15X is officially real and the Navy and Marines are set to get a fresh influx of badly needed aggressor airframes.

www.thedrive.com

And when the Air Force ANG units actually fly regularly with that configuration let me know.

I'll bet they do that sooner than F-35s will fly with 6 AIM-120s internally.

A beer of your choice <= $50. Lot 15 arrives in CY2023...same time at F-15EX IOC.

Except technically it's already flying in that configuration in the form of the F-15SA, QA, etc. 6 AIM-120s internally on an F-35 is still a powerpoint.

Except the ANG doesn't have it yet so quite how they could be flying regularly with that load out is...curious.

 

[trose213]

The F-35 can't even make it to contested airspace before running out of gas

F15EX carries 23,000 lbs of fuel (including cft which have a higher drag profile as compared to bags which eat up hardpoints for A-g ordnance) and burns it through 2 engines.

F35 carries 19,000 lbs of fuel and burns it through a single more efficient engine.

I don't see how you made that comparison.

Have you looked up the combat range of a stealthily configured F-35 vs a normal F-15EX combat loadout? Hint: one is more than 50% longer than the other.

 

[TomS]

Quick question. When the procurement of F-15X for the USAF was first discussed, Boeing was offering both a single-seat CX and a two-seat EX. Do we know for sure that the plan has converged on just the two-seat EX configuration?

 

[yasotay]

Question about aggressor squadrons in the US
since the US has the money and network to acquire actual Soviet/Russian types, maybe even Chinese types
could they build an aggressor squadron using actual aggressor aircraft?

Who's to say they haven't?

Big difference in acquiring one or two aircraft to compare performance, and maintaining a units worth. Maintenance and data systems integration can be very expensive. Why not just buy some flight time on the aircraft in foreign countries then mimic performance with your own systems.

 

[GARGEAN]

That usually is strickly controlled by export contracts of said airframes. Applicable to any mil tech, not only jets.

 

[trose213]

Quick question. When the procurement of F-15X for the USAF was first discussed, Boeing was offering both a single-seat CX and a two-seat EX. Do we know for sure that the plan has converged on just the two-seat EX configuration?

Supposedly, they bought in the 2 seat configuration because it was available for production quicker.

 

[quellish]

Question about aggressor squadrons in the US
since the US has the money and network to acquire actual Soviet/Russian types, maybe even Chinese types
could they build an aggressor squadron using actual aggressor aircraft?

They did. From the 70s to the 90s (?) the US operated a dedicated aggressor / DACT squadron of Soviet / Chinese aircraft. The squadron was called the Red Eagles, based at TTR, and was secret while it was operational.

A separate unit, the Red Hats, flight tests Soviet / Chinese / Etc. aircraft. The Red Hats still operate from Groom Lake and Edwards.

 

[BDF]

Have you looked up the combat range of a stealthily configured F-35 vs a normal F-15EX combat loadout? Hint: one is more than 50% longer than the other.

That doesn't seem right. Looking at older 90s era perf data for F-15CD with -220 motors with EFTs (with AMRAAM launchers) is a drag index of 6.3. Optimum cruise shows a SR of 0.095lbs/nmi. STT + Climb + Combat + Descent and 14% reserves shows about 14.9K of fuel for ingress/egress. That's about 710nm. The F-35 combat radius is 760nm w/ 4 AAMs according LM and probably a tad less with 6 AAMs. Granted the new Eagles with GE '129 motors will be more efficient and may allow for more efficient cruise altitudes but you also have to factor in the increased DI for external stores. So I don't see any realistic way that the 'EX has 50% more range in a AA scenario than the F-35. Mind you I want to get Raptors to the fight first but they're a different kettle of fish...

 

[BDF]

Question about aggressor squadrons in the US
since the US has the money and network to acquire actual Soviet/Russian types, maybe even Chinese types
could they build an aggressor squadron using actual aggressor aircraft?

They did. From the 70s to the 90s (?) the US operated a dedicated aggressor / DACT squadron of Soviet / Chinese aircraft. The squadron was called the Red Eagles, based at TTR, and was secret while it was operational.

A separate unit, the Red Hats, flight tests Soviet / Chinese / Etc. aircraft. The Red Hats still operate from Groom Lake and Edwards.

There's some pics floating around from the early 2000s with what appears to be a Flanker series engaged in BFM over the NTTR....

 

[trose213]

Have you looked up the combat range of a stealthily configured F-35 vs a normal F-15EX combat loadout? Hint: one is more than 50% longer than the other.

That doesn't seem right. Looking at older 90s era perf data for F-15CD with -220 motors with EFTs (with AMRAAM launchers) is a drag index of 6.3. Optimum cruise shows a SR of 0.095lbs/nmi. STT + Climb + Combat + Descent and 14% reserves shows about 14.9K of fuel for ingress/egress. That's about 710nm. The F-35 combat radius is 760nm w/ 4 AAMs according LM and probably a tad less with 6 AAMs. Granted the new Eagles with GE '129 motors will be more efficient and may allow for more efficient cruise altitudes but you also have to factor in the increased DI for external stores. So I don't see any realistic way that the 'EX has 50% more range in a AA scenario than the F-35. Mind you I want to get Raptors to the fight first but they're a different kettle of fish...

It's 670nm, maybe with GO-1. Always take manufacturer's stated figures skeptically.

https://www.airforcemag.com/PDF/MagazineArchive/PublishingImages/2019/May%202019/F-15.F-35_Vertical.v30.pdf

 

[marauder2048]

Have you looked up the combat range of a stealthily configured F-35 vs a normal F-15EX combat loadout? Hint: one is more than 50% longer than the other.

That doesn't seem right. Looking at older 90s era perf data for F-15CD with -220 motors with EFTs (with AMRAAM launchers) is a drag index of 6.3. Optimum cruise shows a SR of 0.095lbs/nmi. STT + Climb + Combat + Descent and 14% reserves shows about 14.9K of fuel for ingress/egress. That's about 710nm. The F-35 combat radius is 760nm w/ 4 AAMs according LM and probably a tad less with 6 AAMs. Granted the new Eagles with GE '129 motors will be more efficient and may allow for more efficient cruise altitudes but you also have to factor in the increased DI for external stores. So I don't see any realistic way that the 'EX has 50% more range in a AA scenario than the F-35. Mind you I want to get Raptors to the fight first but they're a different kettle of fish...

It's 670nm, maybe with GO-1. Always take manufacturer's stated figures skeptically.

https://www.airforcemag.com/PDF/MagazineArchive/PublishingImages/2019/May%202019/F-15.F-35_Vertical.v30.pdf

670 nm is the demonstrated perf figure from the SAR. That's not GO-1.

 

[trose213]

Have you looked up the combat range of a stealthily configured F-35 vs a normal F-15EX combat loadout? Hint: one is more than 50% longer than the other.

That doesn't seem right. Looking at older 90s era perf data for F-15CD with -220 motors with EFTs (with AMRAAM launchers) is a drag index of 6.3. Optimum cruise shows a SR of 0.095lbs/nmi. STT + Climb + Combat + Descent and 14% reserves shows about 14.9K of fuel for ingress/egress. That's about 710nm. The F-35 combat radius is 760nm w/ 4 AAMs according LM and probably a tad less with 6 AAMs. Granted the new Eagles with GE '129 motors will be more efficient and may allow for more efficient cruise altitudes but you also have to factor in the increased DI for external stores. So I don't see any realistic way that the 'EX has 50% more range in a AA scenario than the F-35. Mind you I want to get Raptors to the fight first but they're a different kettle of fish...

It's 670nm, maybe with GO-1. Always take manufacturer's stated figures skeptically.

https://www.airforcemag.com/PDF/MagazineArchive/PublishingImages/2019/May%202019/F-15.F-35_Vertical.v30.pdf

670 nm is the demonstrated perf figure from the SAR. That's not GO-1.

You quoted a 760nm figure.

 

[marauder2048]

Have you looked up the combat range of a stealthily configured F-35 vs a normal F-15EX combat loadout? Hint: one is more than 50% longer than the other.

That doesn't seem right. Looking at older 90s era perf data for F-15CD with -220 motors with EFTs (with AMRAAM launchers) is a drag index of 6.3. Optimum cruise shows a SR of 0.095lbs/nmi. STT + Climb + Combat + Descent and 14% reserves shows about 14.9K of fuel for ingress/egress. That's about 710nm. The F-35 combat radius is 760nm w/ 4 AAMs according LM and probably a tad less with 6 AAMs. Granted the new Eagles with GE '129 motors will be more efficient and may allow for more efficient cruise altitudes but you also have to factor in the increased DI for external stores. So I don't see any realistic way that the 'EX has 50% more range in a AA scenario than the F-35. Mind you I want to get Raptors to the fight first but they're a different kettle of fish...

It's 670nm, maybe with GO-1. Always take manufacturer's stated figures skeptically.

https://www.airforcemag.com/PDF/MagazineArchive/PublishingImages/2019/May%202019/F-15.F-35_Vertical.v30.pdf

670 nm is the demonstrated perf figure from the SAR. That's not GO-1.

You quoted a 760nm figure.

I said nothing about range. The point is the 670 is without GO-1 but presumably with two 2k JDAMs and 2 AIM-120s.
If you want just 6 AIM-120s please feel free to recompute.

 

[BDF]

I said nothing about range. The point is the 670 is without GO-1 but presumably with two 2k JDAMs and 2 AIM-120s.
If you want just 6 AIM-120s please feel free to recompute.

Exactly this. The SAR range was for 2 2K JDAMs and 2 '120s as Marauder says. LM has stated the A-A only configured range with 4 '120s is 760nm. Also there's no way that the 'EX goes 1,100nm with just EFTs. A quick computation off the F-15C/D perf data would suggest that this is only possible with 3 bags and EFTs and I'm guessing 8 AAMs.

 

[marauder2048]

I said nothing about range. The point is the 670 is without GO-1 but presumably with two 2k JDAMs and 2 AIM-120s.
If you want just 6 AIM-120s please feel free to recompute.

Exactly this. The SAR range was for 2 2K JDAMs and 2 '120s as Marauder says. LM has stated the A-A only configured range with 4 '120s is 760nm. Also there's no way that the 'EX goes 1,100nm with just EFTs. A quick computation off the F-15C/D perf data would suggest that this is only possible with 3 bags and EFTs and I'm guessing 8 AAMs.

In the 36,000 lbs of fuel F-15E configuration, you'll pretty much burn most of the centerline tank between ground-ops, taxi, takeoff and climb to altitude.
Assume you drop the centerline tank thereafter.

That gives you ~ 31,000 lbs to play with. Max range fuel flow in the configuration described above is ~ 8500 pph @ 450 knots.
Once you factor in recovery (2000 lbs) and reserves (2400 lbs) that's a radius of 716 nautical miles.
And that assumes absolutely no combat maneuvering fuel flow rates.

Or for 36,000 pounds of fuel, the expeditionary planner elects to operate two F-35As.

 

[BDF]

In the 36,000 lbs of fuel F-15E configuration, you'll pretty much burn most of the centerline tank between ground-ops, taxi, takeoff and climb to altitude.
Assume you drop the centerline tank thereafter.

That gives you ~ 31,000 lbs to play with. Max range fuel flow in the configuration described above is ~ 8500 pph @ 450 knots.
Once you factor in recovery (2000 lbs) and reserves (2400 lbs) that's a radius of 716 nautical miles.
And that assumes absolutely no combat maneuvering fuel flow rates.

Or for 36,000 pounds of fuel, the expeditionary planner elects to operate two F-35As.

So I'm referencing TO 1F-15A-1 which is publicly available on the interwebs. Its for the F15A-D and the E may have some somewhat different numbers. Loading it up with 3 bags, 2 EFTs and 8 AAMs gives a total DI of 42.5. The max weight on the charts is 70K lbs and we're talking about ~72K lb F-15E(X) here but close enough. I get 1500lbs for Start, Taxi and TO with another 2,300lbs for Mil Thrust climb to optimum cruise at this weight/DI of 33,000 ft. Starting specific range is 0.07lb/nm at M 0.88 which is 505kts on a standard day; or about 7,200 pph. I took the estimated starting SR and ending SR and averaged it for a guesstimated SR for the entire cruise segment. MilSpec reserve fuel is 14% but I can't remember if that's for total or just internal. I just went with internal but counted the CFT towards that value. So I get, 3800lbs for S.T.T and Climb. Roughly 13,000lbs and 1050nm expended each way with 2000lbs of combat fuel (2 min at max AB @ 20Kft.) Descent is 300lbs and 60nm. Fuel remaining is 4,100lbs and total radius is 1,115nm.

So I'm coming up with more range but also much lower SR. Basically it's going to cost you 40% more fuel per mile in the F-15 but to be fair you can plan for shorter distances and drop the high drag CL external tank or even to w/out tanks all together. The latter config is shorter range than the F-35 when spec'd for A-A only. In any case I'm in agreement, I think the argument for 200 'EXs is weak. I'm ok with 2-3 years of production.

 

[eagle]

I got a range of 2050 nm or a radius of 1025 nm for an air to air configured F-15E, with 8 AAMs, 3 tanks and CFTs. All retained.
Sidenote: with hypothetical -3 CFTs, the range would increase to 2285 nm.
But those are my calculations from some time ago.

Anyway, here's some official numbers:
Boeing claims a 1100 nm plus radius for an unknown configuration.
The F-15C Standard Aircraft Characteristics mission table gives a radius of 770 nm with 4 AIM-7, 2 Mk 84 and CFTs, no tanks.
With a center tank, the radius is 836 nm or 891 nm with tank dropped.
Ferry range is given as 2294 nm or 2582 nm with tanks dropped. That is a 3 tanker with 1540 lbs of fuel offloaded to meet maximum gross weight limits.

So a 1000 nm plus radius seems feasible to me for an air to air F-15EX.

 

[marauder2048]

Looking at the 1991 F-15E Flight Manual again (1F-15E-1):

The F-15E with 3 x EFTs, CFTs, 2 x LAU-128/2 AIM-120s each, 4 x AIM-120s on the CFTs + Legion Pod* has a GTOW of 76,038 lbs.
That's a Drag Index of 70 and 35,500 lbs of fuel.
I still get 8500 PPH @ 450 knots as optimal range.

*Guess a DI of 7.1

 

[helmutkohl]

somewhat related
Boeing's new major upgrade with Mitsubishi for the F-15
how much of the EX tech is transferring over to this? if any?

Boeing, Mitsubishi Heavy Industries Partner on State of the Art Upgrades to Japan’s F-15J fleet

TOKYO, July 28, 2020 - Boeing and Mitsubishi Heavy Industries (MHI) recently signed a Direct Commercial Sale agreement to support upgrades to Japan’s F-15J fleet.

boeing.mediaroom.com

 

[BDF]

Looking at the 1991 F-15E Flight Manual again (1F-15E-1):

The F-15E with 3 x EFTs, CFTs, 2 x LAU-128/2 AIM-120s each, 4 x AIM-120s on the CFTs + Legion Pod* has a GTOW of 76,038 lbs.
That's a Drag Index of 70 and 35,500 lbs of fuel.
I still get 8500 PPH @ 450 knots as optimal range.

*Guess a DI of 7.1

Strange, I went back and double checked my reference and while I did note that I left off the two SUU-59 wing pylons I don't get near a DI of 70. I have the following:

• F-15D 2.3
• 2 CFT 4.0
• 4 '120 on CFT 5.2
• 2 '120 on LAU-128 4.8
• 2 '9M on LAU-128 3.0
• 2 SUU-59 pylons 6.6
• 2 610 EFT 11.0
• 1 610 CL EFT 12.2

Total DI of 49.1 Wonder if F-15E is more draggy for some odd reason? Are the AAQ-13 & 14 accounted for and that's driving up the DI? Kinda strange.

 

[marauder2048]

Looking at the 1991 F-15E Flight Manual again (1F-15E-1):

The F-15E with 3 x EFTs, CFTs, 2 x LAU-128/2 AIM-120s each, 4 x AIM-120s on the CFTs + Legion Pod* has a GTOW of 76,038 lbs.
That's a Drag Index of 70 and 35,500 lbs of fuel.
I still get 8500 PPH @ 450 knots as optimal range.

*Guess a DI of 7.1

Strange, I went back and double checked my reference and while I did note that I left off the two SUU-59 wing pylons I don't get near a DI of 70. I have the following:

• F-15D 2.3
• 2 CFT 4.0
• 4 '120 on CFT 5.2
• 2 '120 on LAU-128 4.8
• 2 '9M on LAU-128 3.0
• 2 SUU-59 pylons 6.6
• 2 610 EFT 11.0
• 1 610 CL EFT 12.2

Total DI of 49.1 Wonder if F-15E is more draggy for some odd reason? Are the AAQ-13 & 14 accounted for and that's driving up the DI? Kinda strange.

The CFTs on the F-15E alone have a DI of at least 20.5 (there's another source with 21.5)
And once you start hanging stores off of them, the DI of the EFTs on the wing stations go up.

 

[stealthflanker]

What cooling method the F-15, especially the latest one use ? I would assume liquid cooling, if it's indeed liquid then does it use fuel as the heatsink to dump the heat ? Finally regarding the CFT's does the CFT fuel can be made available for cooling purpose ?

 

[TomcatViP]

It would come as a nice surprise if Boeing put the money to do that.

 

[trose213]

Anyone find it bizarre that Boeing hasn't been aggressively bidding the F-15EX in international competitions? There have been rumors of India.

F-15EX Could Replace Strike Eagle Fleet, in Addition to Older C/D Models, USAF Says | Air & Space Forces Magazine

USAF may replace its 218 F-15Es with F-15EXs, which could expand the new program to over 400 aircraft, according to service documents.

www.airforcemag.com

 

[Archibald]

Boeing "you opened the Pandora box, buying brand new F-15s for the first time since 2001. Now, nothing will stop me".

We are lucky Lockheed has the F-35 to screw the F-16 in USAF service, otherwise you guess, they would have tried their chance... "how about buying F-16 Block 60 ?"

 

[Moose]

EX is heavily based on export Eagle variants, there aren't a ton of large fighter competitions going a this precise moment, and they've had to tread pretty carefully when selling this buy to Congress. So, no I don't find anything bizzare there.

 

[TomcatViP]

I see it as perfectly normal too. Instead of spending money tightening loose nuts you pay for an upgraded airframe.
If the world had catch-up with USAF's stealth technology, things would have been different for sure.

 

[yasotay]

I see it as perfectly normal too. Instead of spending money tightening loose nuts you pay for an upgraded airframe.
If the world had catch-up with USAF's stealth technology, things would have been different for sure.

It keeps the industrial base viable as well.

 

[trose213]

EX is heavily based on export Eagle variants, there aren't a ton of large fighter competitions going a this precise moment, and they've had to tread pretty carefully when selling this buy to Congress. So, no I don't find anything bizzare there.

I had Canada, Germany and Finland in mind specifically.

 

[TomcatViP]

Obviously, if you'r ready to buy a Rafale, you'd better go with an E[X]agle.

 

[Moose]

EX is heavily based on export Eagle variants, there aren't a ton of large fighter competitions going a this precise moment, and they've had to tread pretty carefully when selling this buy to Congress. So, no I don't find anything bizzare there.

I had Canada, Germany and Finland in mind specifically.

Canada and Finland are not looking at Eagle-sized aircraft, Boeing bid Super Hornet for both. Germany's program is.... well its complicated.

 

[Trident]

Indeed. Basically, there are 3 attributes to consider, in addition to preferably maintaining the German industrial base (which is realistically the only reason Typhoon figures in the plans):

- be a good strike platform to replace Tornado IDS, including B61 capability.
- have a strong EW/SEAD capability
- be stealthy

Typhoon doesn't really provide any of this out of the box, although industry is proposing an ECR version that would take care of the second item (but is probably too expensive as a bespoke development). F-35 does very well on #1 and 3, but doesn't have #2 and is viewed as potentially damaging to the prospects of the NGF project (I don't necessarily agree, see UK & Italy). Meanwhile the Super Hornet is the gold standard on #2 and performs very respectably on #1 (B61 integration pending).

The F-15? Well, it fulfills #1 possibly better than any other candidate, but beyond that doesn't have much going for it. With the two US alternatives each ticking two of the three boxes, it's clear why the Eagle doesn't figure prominently.

If money were no object, F-35 & Typhoon ECR would be the way to go. If politics were no object, Growler and F-35 would look attractive. Failing both, you arrive at the proposed, decidedly unsatisfactory solution of Typhoon + SH/Growler, because without significant bespoke development you only really get to pick any two of the three items.

 

[marauder2048]

"how about buying F-16 Block 60 ?"

Because new build Block 60's would make new build F-15EX look catastrophically stupid rather than
just moderately stupid.

 

[marauder2048]

I see it as perfectly normal too. Instead of spending money tightening loose nuts you pay for an upgraded airframe.
If the world had catch-up with USAF's stealth technology, things would have been different for sure.

It keeps the industrial base viable as well.

Just viable for the F-15. It's unclear that having a hot production line enables you to win future competitions:

Boeing is the only manufacturer of attack helicopters for the Army; they failed to even place in a program that will
replace half of the attack helicopters in Army service.

Note that "industrial base" is absent from any of the justifications used for "other than full and open competition."

You have to be able to prove these things above a GAO protest; the AF couldn't do this even with the non
industrial-base justification for the engines. It crumbled under a protest.

 

[trose213]

EX is heavily based on export Eagle variants, there aren't a ton of large fighter competitions going a this precise moment, and they've had to tread pretty carefully when selling this buy to Congress. So, no I don't find anything bizzare there.

I had Canada, Germany and Finland in mind specifically.

Canada and Finland are not looking at Eagle-sized aircraft, Boeing bid Super Hornet for both. Germany's program is.... well its complicated.

The Super Hornet is getting up there. The only real advantage would be re-using the Hornet infrastructure.

Indeed. Basically, there are 3 attributes to consider, in addition to preferably maintaining the German industrial base (which is realistically the only reason Typhoon figures in the plans):

- be a good strike platform to replace Tornado IDS, including B61 capability.
- have a strong EW/SEAD capability
- be stealthy

Typhoon doesn't really provide any of this out of the box, although industry is proposing an ECR version that would take care of the second item (but is probably too expensive as a bespoke development). F-35 does very well on #1 and 3, but doesn't have #2 and is viewed as potentially damaging to the prospects of the NGF project (I don't necessarily agree, see UK & Italy). Meanwhile the Super Hornet is the gold standard on #2 and performs very respectably on #1 (B61 integration pending).

The F-15? Well, it fulfills #1 possibly better than any other candidate, but beyond that doesn't have much going for it. With the two US alternatives each ticking two of the three boxes, it's clear why the Eagle doesn't figure prominently.

If money were no object, F-35 & Typhoon ECR would be the way to go. If politics were no object, Growler and F-35 would look attractive. Failing both, you arrive at the proposed, decidedly unsatisfactory solution of Typhoon + SH/Growler, because without significant bespoke development you only really get to pick any two of the three items.

The USAF is looking at the F-15EX for jamming duties, now that the F-35 isn't getting the NGJ.

 

[marauder2048]

The USAF is looking at the F-15EX for jamming duties, now that the F-35 isn't getting the NGJ.

The mid-band pod design for NGJ practically precludes its use on any aircraft other than the Growler.

The low-band pod maybe but the fact that the Navy is pursuing MALD-N and AARGM-ER is evidence
that they don't think the Growler's jamming efficacy is sufficient.

 

[Josh_TN]

What about the NGJ precludes its use on other aircraft?