Forum: General

Has anyone ever seen an ISA driven flight control surface move slower than the opposite side? Have a problem with Stab surface not moving assymetrically, there seems to be a .5 to 1 second delay between the left and right surfaces. Aircraft passes self-test and Hydraulic malfunction checks.

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Did you put cross over cables on it? It could be some of the ISA's solenoids...maybe

Crossover cables will isolate the ISA. Digital or Analog FLCS?

Back in the day.....

It would "cost" the B-shopper (me) a case of beer to the Hydraulics guys that changed an ISA if that didn't fix the problem.

Smitty

we put cross over cables on, and determined the ISA needed to be changed. Yet the ISA still passes the self test. There is no reference to this type of problem in the FI. Up till now it just depends on experience to make the call if it is good or bad.

I think you should start working on a AFTO form 22 and get yourself some money... maybe.
Contact your QA or AFETS, they can help you

If it passes the Self test and works ok. Let it ride till the next phase. ISA,s always seem to have a mind of there own.

We had one surface that worked fine. But on start would flutter for about 10 to 15 seconds. Everytime. Only the one surface.

MakoWes wrote:

If it passes the Self test and works ok. Let it ride till the next phase. ISA,s always seem to have a mind of there own.

We had one surface that worked fine. But on start would flutter for about 10 to 15 seconds. Everytime. Only the one surface.

Too be honest with you … that’s the sillyest thing I’ve ever read when it comes to F-16 maintenance?

Phuck phase, fix you’r own sh*t when you know its bad. Doh

Seems when an ISA starts to lag behind the other one, it is a tell tale sign it is about to hard fail. I'm changing it ASAP. Just wish I could convince LM that there needs to be a fault code put into the 27FI. I'm still working that issue and will continue to do so.

Expat58 wrote:

we put cross over cables on, and determined the ISA needed to be changed. Yet the ISA still passes the self test. There is no reference to this type of problem in the FI. Up till now it just depends on experience to make the call if it is good or bad.

There are 3 servo valves in each ISA. SV1 and 2 act as primaries and 3 as a back up. FLCS will still pass with 1 or even 2 servo valves bad since you still have the third to take over. Put the EDNA on it and do a monitor bit. It'll show you the bad servo valves. We had this problem on a jet at Luke. I would bet a lot of money it's a bad ISA.

Just wondering how this got noticed? Was it by chance that someone noticed it during FLCS test or did some flyboy complain about a rolling motion every time pitch was applied?

Expat58 wrote:

Seems when an ISA starts to lag behind the other one, it is a tell tale sign it is about to hard fail. I'm changing it ASAP. Just wish I could convince LM that there needs to be a fault code put into the 27FI. I'm still working that issue and will continue to do so.

Not completely true. Even if LM agrees with you, CTOCU might shoot you down. This is a rare problem, and you managed to troubleshoot it despite the fact that there is not a current fault code. Many times the cost of incorporating a change such as this in the 27FI (or any TO) doesn't justify making the change. If every one-of-a-kind failure such as this was added to the 27FI, how thick would it be then? Even if it's not one-of-a-kind, it certainly is rare. You just can't justify the cost of making the change.

Best Regards,

Crew Cheif saw it on launch, and started complaining it wasn't equal with the left stab. We did use the EDNA, performed a self test, and a manual control check out, all passed with flying colors, yet you could notice the right stab falling behind. Customer started complaining LM wasn't fixing the jets and they weren't safe to fly. Lost a "little face", sucking it up, and moving on. Either they'll get over it or they won't. They don't realize there trying to fly block 10 & 15's like they are new. How many 30 year old cars you see driving back and forth to work at 100mph everyday with out breaking down Nuff said !!

Too be honest with you … that’s the sillyest thing I’ve ever read when it comes to F-16 maintenance?

Phuck phase, fix you’r own sh*t when you know its bad. :doh:[/quote]

So, You want to break a jet when its not broke. Eveything works fine. And on the schedule. With a part that is hard to get?

No thats silly.

In the Reserve we work the Line and Phase. We will fix our own sh*t. But we do it smart. When the plane is already down. And the panels are off.

In the Reserve we dont have the luxury of breaking good jets. We leave that to the Active Duty guys.

Expat58
So did you change the ISA? If the customer is paying. And he is also complaining. Just go ahead. Crew Chiefs can always use some more training.

Forum: General

Flight Control Problems?