What's going on with the F-15?

reply to post by JimmyCarterIsSmarter


You just very much answered your own question An F-15 airframe will have more stress applied to it than a 747 airframe for instance.

Subsequently operational use was more severely stressful than the original design specification. With an average usage of 270 aircraft flight hours per year, by the early 1990s the F-15C fleet was approaching its service-design-life limit of 4,000 flight hours. Following successful airframe structural testing, the F-15C was extended to an 8,000-hour service life limit……..The F-15E structure is rated at 16,000 flight hours, double the lifetime of earlier F-15s.

The entire article can be found here.

Well we have an update on the F-15 status.

US Air Force Boeing F-15E Strike Eagles have been cleared to return to flight. All F-15s had been grounded since the US Air National Guard F-15C crash in Missouri on 2 November caused by suspected structural failure......

The F-15A-Ds are expected to remain grounded until after the accident investigation board submits its report, which is due within 30 days of the crash, says the USAF.
The investigation is focusing on the area aft of the cockpit, where the accident F-15 is reported to have separated in flight during one-versus-one air combat training.

Well personally I think grounding the F-15E/I/S where just out of caution and not surprised at all that they are back up in the air but the C/D issue will be highlight next week (?) when the report is out. At this point they aren't narrowing down at least publicly if it is really a airframe issue though that is most likely. The interesting part will be what reccomendation will be made after this crash.

www.flightglobal.com...

Considering that it broke in half just behind the cockpit, I'd have to say that we're definitely looking at an airframe issue. The interesting thing is that it appears to have fallen straight down in level flight once it broke in two.

reply to post by Zaphod58


I was wondering if it had actually broken apart in flight. That may explain why the Air Force set up a 7 mile perimeter around the crash site for the investigation.

That's why they grounded them. They've had problems with parts of the airframe failing in high stress flight conditions, but this is the first time the entire airframe broke apart. If you look at the pictures of the wreckage, it HAD to have broken apart in flight. You can see from the intakes back, but nothing of the nose or cockpit area. You can even still recognize it as an F-15 from what's left of the wreckage.

A few years ago they discovered that the leading edge of the vertical fin would fail when they lost an aircraft and pilot during a Mach 1.97 dive over the Gulf of Mexico.

[edit on 11/15/2007 by Zaphod58]

Just an FYI, the F-15 was supposed to fly flight demos at the Nellis AFB show, but did not

As an Iowan, I could probably see this from a different angle (by the way, I'm also a former Crew Chief on F-15C's and D's at Langley AFB, VA in the late 80's/early 90's.)

Anyway, those damn Missourians are hard on stuff! I deal with their truck drivers every day at my job. Has anyone looked at the farm-boys flying these planes? While the accidents are "structural failure", I'd be willing to bet that they are flying these 20 year old planes harder than they should. Probably barnstorming underneath that St. Louis archway thing!

I can recall an incident at Langley AFB when I was stationed there of an F-15C coming back with its vertical stabilizers canted "inward" and the outer parts of the horizontal tailerons broken off because the pilot "Over-G'd" the aircraft. The plane was scrapped, and I think the pilot was spanked pretty severely. These aircraft are still from a generation of technology where the "pilot" was truly the master of his aircraft, and not just along for the ride!

[edit on 19-11-2007 by CreeWolf]

Well a large number of the planes are up again and have went through through airframe checks and exams but I havent heard anymore about the invesigation on the F-15C crash. They are saying only this from the small flight global article.

Gen. John D W Corley, commander, Air Combat Command, says: "As of today (21 November), 219 of the 224 E-models and 294 of the 442 A-D models in the inventory have been inspected and cleared for flight."
He says that "the circumstances of the mishap indicated catastrophic structural failure", and that the "cause of the mishap remains under investigation".

www.flightglobal.com...

No way a catastrophic failure tell us somethign we don't know. I'm still interested Zaph in if you have a link to the photos of the crash site and the airframe. The USAF really is trying to keep the media off this and I can't blame em but its time ot get a bit more info then that.

Ask and ye shall receive.

www.katu.com...

This is the only known picture of the latest crash.

I just found these two videos over at patricksaviation.com. Sorry if they've been posted before.

MOANG F-15C breakup animation

MOANG F-15C HUD/audio