747 flight controls

[450knotOffice]

I can understand that for sure. We're constantly being reminded by our chief pilot to be concise with our write-ups.

I happen to be one of those individuals who has been on both sides of the fence - A&P first, pilot later. I certainly have a great deal of respect for our mechanics.

[Zef]

Could not duplicate." How many times have I seen that in 15 years as an airline pilot.

Yea...but an aicraft in flight is a lot different than on the ground...there are problems you can not duplicate on ground...and to repair\troubleshoot it...you have to get the fault...mechanics are not GOD like pilots are...!

[Burnin' oil]

Originally posted by motion
Those sure are purty clouds.

I'm glad I'm not the only one in the room.

[swa911]

Originally posted by zefsuper911
Could not duplicate." How many times have I seen that in 15 years as an airline pilot.

Yea...but an aircraft in flight is a lot different than on the ground...there are problems you can not duplicate on ground...and to repair\troubleshoot it...you have to get the fault...mechanics are not GOD like pilots are...!

Thanks for the support.

Believe me. We only write "could not duplicate" as a last resort. How much money do you want to spend "shot-gunning" parts for some crazy write up like " at FL 370 aircraft seemed to pitch up when the f/o keyed his mic"?

Most pilots are very knowledgeable about the aircraft and the workings of it's systems but there are a few who seem to live to take a/c out of service for some of the most ridiculous reasons. Those are the guys I'm talking about.

Rant over. I'm out.
Merry Christmas.

[Aerkuld]

Couldn't you have stuck your head out of the window to see what the rudder was doing?

[supdaf]

As a matter of fact I was working a similiar problem on a 757 last night. Most likely one would expect the drivers to write up an excessive trim (aileron), with ,maybe, a spoiler warning light. When trouble shooting that problem, spoiler float is looked at early. Now I do not know exactly how a 747-400 works but if it is the same as 757,767 a spoiler actuator replacement should fix the problem.

The spoiler actuator has a position transmitter inside that Boeing calls a LVDT (linear variable differential transformer). When you replace an actuator it is necessary to "null" this transmitter. You have to give the controller a signal that represents effectivly zero. It is possible that this actuator needs re nulled but the adjustment does not normally move on its own so more than likely an actuator should be replaced.

It is normally an easy job, two hours or so. This is what I did last night.

[nostatic]

the flayrob's gone out of skewel on trittle

[450knotOffice]

swa911, I believe that you started the little pissing contest with your swipe toward fingpilot for disagreeing with your diagnosis. How dare he (fing pilot). And zefsuper911, your comment about pilots being GODS was also direct and to the point in your disdain toward us.

So here's my response:

My comment about "could not duplicate" stands. I'll give an example. Since December 12th, one of our airplanes has had it's TCAS written up FIVE times by five different pilots, including me. Every single time the mechanics found nothing wrong with the TCAS and returned it to service. Finally, my first officer noted during his preflight inspection that the TCAS antenna was completely chopped in half but was being held together by the protective leading edge tape. He called me down to look at it and sure enough, the only thing holding the lower portion of the TCAS antenna was indeed the tape. Hmm. It didn't take a genius to guess what was causing the TCAS faults, so I called Maintenance over to take a look at the antenna and casually mentioned that this airplane had had it's TCAS system written up five times in the past six days and that this might have been causing the problem. They agreed and pulled the aircraft from service while awaiting a new antenna. So why didn't maintenance catch this obvious break of the antenna during their previous five diagnosis of the system?

The point of this is that many times maintenance seems to want to take the easy way out and do a quick, simple diagnosis and if they don't find the problem quickly they just return the aircraft to service when all they would need to do is perform a THOROUGH diagnosis (like checking the antenna on a system that requires one to work properly and keeps failing over and over again). Yes, many pilots need to be more concise with their write-ups but, c'mon man, if pilots ding something over and over again while the aircraft is in flight but you can't duplicate it on the ground (yes, we know that many problems can not be duplicated on the ground, zefsuper), then either do a more thorough diagnosis, or yes, start replacing parts, starting with the most likely first. Don't just do nothing over and over again just because you couldn't figure out was was wrong and therefore the pilots must have been dreaming about the failure. Either that, or take it out on a test flight and see for yourself if the fault can't be duplicated on the ground.

[supdaf]

I think that all questions are easy if you already know the answers. Troubleshooting most anything, cars, airplanes or even tricycles is the same way. I would like to think that I and my fellow aircraft maintenance professionals would easily find a broken antenna especially if it is located on the bottom of the fuselage, however I work with some of these guys and in any endevor? abilities go from the best to the worst. All in all the guys I work with are pretty sharp and it suprises me that someone would not inspect the antenna at some point after a repetitive write up.

In all honesty I think we all try to find ways to make our daily chores easier and faster. You can call it laziness or you can spin it to something like productivity. At my company, in our business we are charged with doing more and more with less and less. It is easy to hit the test switch and when you hear the voice say "TCAS system OK" call it good and drive on to the many other things that have to be done before the night is over. How much time did the mechanic have to work on the problem? Was there an antenna fault message present? call them excuses but realize there is another side.

When was the last time you flew multiple legs without the autopilot, autothrottle, or flight management computer? Last night I had to spend time repairing the captains cup holder. No other writeups on the aircraft so if that is all he could find well I guess we are doing a pretty good job down here on the wrench end.

I am not about to knock pilots because we need each other. If it aint fixed you can't fly it and if you don't fly the thing it won't break and I have to fix something else for a living. Kind of like my 911. If it sits in the garage it aint no fun at all.

[swa911]

Hey 450k, I'm not sure what airline you work for but anyone who would not look at the antennas in your example is a dumbass. TCAS antennas are notorious pieces of crap that typically short internally taking the TCAS processor with it. Most TCAS write-ups are fixed by the r&r of the antenna. The damaged antenna should have least been seen on any decent service check walk-around by mx. For that matter why didn't an FO see it sooner?

No one is perfect, not even a pilot.

I made my diagnosis of the 747 problem by going off a picture. Fingpilot immediately wrote it off as if I had no idea what I was talking about. That is what irked me. But seems the consensus from most here who are in the know is that it is definately a floating spoiler caused by a bad actuator. I'm not a 747 guy so I don't know for sure what the aileron is doing. Whether its counteracting through manual trim or A/P input is beyond me.

It is nice to see the true colors of you boys in the front though. I always thought the "we sure appreciate all you do" smiling & handshakes was bull&*%#. Now I know how you really feel.

Merry Christmas.

[Zef]

No one is perfect, not even a pilot.

Yea...but they don't know yet...

[fingpilot]

Frankly, I did'nt want to start a pissing match with anyone. A question was asked about what would cause the condition in the picture. An anaylsis of the picture (including a description from the eyewitness of the stuff not pictured) and the system that controls those surfaces makes that conclusion obvious. In spite of all of this evidence, there were some here have taken exception to the obvious.

Like all professions, there are good mechs out there that will gladly dive into fixing a problem, and there are ones that will try to explain away a writeup rather than do their job. Sadly, there are more of the latter lately, and they are usually the ones squeaking the loudest.

Now that that has been said, I didn't defame anyone here. Unlike some of the comments above.

Merry Christmas to you too.

[fingpilot]

Originally posted by swa911
Sure, but speaking for those of us on the ground with the wrenches in our hands it's just another know-it-all button pusher telling us how to do our jobs.

Herein lies the piss.

[KevinP73]

Another OT thread goes tragically astray

[450knotOffice]

Yup. It was good discussion until swa took offense and threw the little grenade at fing. Was that really necessary? The discussion went downhill from there, of course.

And, yes most every pilot I know respects and appreciates the excellent work that mechanics do to keep the airplanes in the air. It is NOT a bul**** handshake. We really do mean it. Without you guys we would not be working (and like I've said, I was a mechanic before I was a pilot so I do feel like one of you guys {one of our mechs is a Type rated G4 pilot, btw, so it swings both ways})

[swa911]

It's all good my friends.

I will man up and say I'm sorry to any and all I have offended. This is not the place I want to piss anyone off since I have made some very good friends on Pelican. I took offense to an innocent comment and it just went crazy from there for no real apparent reason. So, to 450K, fingpilot, and any other pilots who may have read this please accept my apology.
I am not the jerk my posts on this thread made me out to be. As I read back through them it was pretty embarassing the things I typed.

Truce?

[KevinP73]

With the number of airline disasters lately, the FAA sends an inspector to the North Pole to check out Santa Claus' sleigh before allowing him to fly on Christmas eve.
The inspector arrives and checks the reindeer and they look good.

He checks the harness and it looks okay.

He checks the sleigh and it is also okay.

Then he says, "Santa, lets take it up for a check ride and if everything looks good I'll certify you to fly."

Santa hitches the reindeer up and taxis onto the runway and, just as he's starting his takeoff slide, he looks over and notices the inspector has a pump shotgun on his lap. "Hey! What's the shotgun for!?" Santa yells.

The FAA inspector says, "Well, Santa, I'm really not supposed to tell you this, but there is going to be a simulated engine failure on takeoff."

[84porsche]

Kevin,

That's awesome.

[450knotOffice]

Kevin, that was funny!! I laughed out loud for that one.

swa...truce, my friend.

[Tom Z.]

This is almost certainly a floating flight spoiler. Flight spoilers typically are operated by only one hydraulic system, as opposed to two for the ground spoilers. The float occurs when the actuator bypasses internally, allowing the low pressure to lift the panel. The amount of panel lift is in direct proportion to the lift created by the wing (and thus low pressure) and is not really related to airspeed. On a Boeing there is no mechanical device to hold flight spoilers stowed without hydraulic pressure, unlike DC-9's & MD-80's. Since the spoiler panel is raised, a loss of lift occurs, which requires a counter input to keep the wing level.

The amount of aileron deflection appears to be a lot, but remember that it's an inboard aileron without much roll-inducing horsepower. The opposite inboard aileron wouldn't show nearly this much deflection due to the assymetrical travel of ailerons... the downward aileron always travels further than the upward aileron. Chances are that the upward-travelling aileron still appeared faired. This plane is going to burn a lot of extra fuel in this condition, especially on a long flight!

This is almost certainly NOT an example of a misrigged flight control because of the onerous double and triple-checking and inspecting that accompanies rigging procedures. Even more attention to rigging is paid these days due to fuel costs. On top of that, an error in rigging of this magnitude is pretty obvious!

My $.02 worth from an Boeing-qualified airline maintenance instructor, although not a 747 instructor.