Monocleman
Topic Author
Posts: 133
Joined: Fri Apr 27, 2001 10:21 am

Most Stressed Part

Fri Aug 10, 2001 12:32 pm

In the opinion of the engineers and mechs and all others in the forum, what do you think is the single part of an a/c that is stressed the most? To me it seems to be the landing gear, because of all the restrictions put on them and the many subleties of them. But I may be proven wrong by all of you - lets see.

-Will
 
DE727UPS
Posts: 810
Joined: Wed Nov 22, 2000 10:55 am

RE: Most Stressed Part

Fri Aug 10, 2001 1:21 pm

Without a doubt....the most stressed part in an aircraft is the pilot....

We have to put up with long duty periods, working at night, short rest times, schedules that are created by computers with no thought to quality of life, and maids in hotels that ignore the do not disturb sign. These stress factors...acting together....have caused more aircraft accidents than airframe parts ever will.

Now...I dare you to ask about aircraft fatigue....
 
aaron atp
Posts: 517
Joined: Sun Mar 19, 2000 1:17 pm

Flaps

Fri Aug 10, 2001 1:44 pm

I would have to say that the items most likely to meet their designed stress level most often would be flaps and their tracks/operating mechanisms.

It's hard to compare absolute stress levels, but by the method
((actual stress encountered) / (design stress)) * 100% = relative stress

I would say that flaps are most likely to reach 100% of rated stress for two reasons.

1. It is easier to (e.g. pilots are more likely to) exceed the design flap speed than to make a hard landing that meets the gears design strength

which leads to

2. Gear are designed with a relatively higher margin between design stress and absolute stress than the flaps.


From a statics standpoint, just think about the enormous moments produced by multi-slotted flowler flaps at full extension, not to mention the drag component causing those moments.


aaron



 
Twotterwrench
Posts: 1087
Joined: Tue Jan 16, 2001 5:57 pm

RE: Most Stressed Part

Fri Aug 10, 2001 2:26 pm

OMG!! Pilot's stressed???? I... must.. bite.. my .... tongue... must... not ....succomb... to... flame....bait....work....12...days...a....month....and....call.....it....stress....bite...tongue....bite...tongue.....bite...tongue....ok..I am alright now..
 
L-188
Posts: 29881
Joined: Wed Jul 07, 1999 11:27 am

RE: Most Stressed Part

Fri Aug 10, 2001 6:21 pm

Trotterwrench....I think you need to put your signature on something........ Laugh out loud

I the connecting rods on a piston engine.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
 
JT-8D
Posts: 423
Joined: Sun Dec 31, 2000 11:34 pm

RE: Most Stressed Part

Fri Aug 10, 2001 6:48 pm

Yea that 2 weeks a month work schedule must really be a bitch. Ive got it easy. I work nights, get 5-6 hours of sleep a day, and have a paycheck smaller then yours. I bit my tongue too. But my god, whining that loud has to be commented on..JT
 
Monocleman
Topic Author
Posts: 133
Joined: Fri Apr 27, 2001 10:21 am

RE: Most Stressed Part

Sat Aug 11, 2001 6:23 am

LOL Twotterwrench... but really, what do you think is the most physically stressed part?
 
Twotterwrench
Posts: 1087
Joined: Tue Jan 16, 2001 5:57 pm

RE: Most Stressed Part

Sat Aug 11, 2001 6:55 am

As far as piston engines go, I would agree with L-188. The rods take a whoppin. I also think horizontal stabilizer attach points are a big area of stress. Lots of aging aircraft inspections focus on this area. Engine bearings in the hot section are subject to a lot of abuse. Thrust reversers. Brakes. Point is, all of these areas are stressed, but designed to withstand 150% of their normal loading in most cases.
 
242
Posts: 495
Joined: Tue Oct 24, 2000 1:10 pm

RE: Most Stressed Part

Sat Aug 11, 2001 12:39 pm

>>>maids in hotels that ignore the do not disturb sign. <<<

You should consider yourself lucky to get a hotel room. Many times I've been sent out to an outstation late at night to fix an aircraft only to have the company expect me to sleep on the plane.

It's guys like you, DE727UPS, that make me smile when I put an autopilot on MEL.
 
flightsimfreak
Posts: 698
Joined: Sun Oct 29, 2000 9:36 am

RE: Most Stressed Part

Sat Aug 11, 2001 2:42 pm

obviously the most stressed part of the airplane is my instructor (just kidding) I'de agree with you that the landing gear are probably the most stressed part of the plane... especially with my landings (Again just kidding)
 
FDXmech
Posts: 3219
Joined: Sun Mar 19, 2000 9:48 pm

RE: Most Stressed Part

Sat Aug 11, 2001 6:17 pm

The engine high pressure turbine blades during take off.
Interesting fact is approx 85% of engine failures occur during maximum power take offs.
You're only as good as your last departure.
 
metroman
Posts: 32
Joined: Wed Apr 18, 2007 9:32 pm

RE: Most Stressed Part

Mon Aug 13, 2001 3:01 am

The arm rests on the crew seats. You would think that they were the most intrical part of the A/C the way the Flight Crews act when they break.

Seriously, my opinion? No other part is subjected to more NDT than the main wheels, nor does any other part have such a high rejection rate.
 
Twotterwrench
Posts: 1087
Joined: Tue Jan 16, 2001 5:57 pm

RE: Most Stressed Part

Mon Aug 13, 2001 4:10 am

Don't forget cupholders, metroman! God forbid they should have to fly without one of these. I have actually had a pilot refuse to take an aircraft because there were no cup holders in the cockpit. Maybe he could get the maid to bring him some coffee, but only AFTER he takes down the do not disturb sign...
 
metroman
Posts: 32
Joined: Wed Apr 18, 2007 9:32 pm

RE: Most Stressed Part

Mon Aug 13, 2001 10:45 am

Twotterwrench, that's true! I used to remove the cupholders from the cockpit when I wanted punish a particular "Bed Wetter", I mean pilot. That usually got their attention. Reinstallation fee was an apology and a six-pack of Moosehead.
 
delta-flyer
Posts: 2631
Joined: Mon Jul 30, 2001 9:47 am

RE: Most Stressed Part

Mon Aug 13, 2001 10:55 am

Don't forget the skin! Inflates and deflates like a balloon once per cylce?
"In God we trust, everyone else bring data"
 
242
Posts: 495
Joined: Tue Oct 24, 2000 1:10 pm

RE: Most Stressed Part

Mon Aug 13, 2001 11:23 am

Cupholders? Why that's what the center control stand is for! It's not unusual to find a corrective action for an autopilot gripe that reads: "Found spilled coffee in autopilot control panel, none in stock, move to MEL log #xyxx, cat c, exp xx/xx/xx."
 
metroman
Posts: 32
Joined: Wed Apr 18, 2007 9:32 pm

RE: Most Stressed Part

Mon Aug 13, 2001 11:49 am

242,

So now you have doubled the workload of the 1st "Bed Wetter", I mean Officer. Now he has to hold two cups of coffee.

Shame on you, it is the duty of all A&P's to exhaust all possible means of corrective action to relieve the "Bed Wetters", I mean Flight Crews, of unnecessary work loads.
 
Twotterwrench
Posts: 1087
Joined: Tue Jan 16, 2001 5:57 pm

RE: Most Stressed Part

Mon Aug 13, 2001 12:15 pm

One time I got to work a gripe where the pilot claimed he couldn't slide his seat back. First I pulled out the apple core that looked about 6 weeks old. Then I removed what was left of the wadded up Playboy he left wedged behind his seat. Several soda cans, 2 coffee cups and a chew can came next. Then, I got to stick my fingers straight into his cup of chew spit he had neglected to throw away when he went home that day. Soooooo... I took the whole mess and dumped it out in his flight bag. And you fly boys wonder why we don't like you.. is it that hard to figure out????

By the way, after I got done playing maid for this trailer park slob, the seat worked just fine...
 
Guest

RE: Most Stressed Part

Mon Aug 13, 2001 12:16 pm

Why can't pilots and mechanics just get along?
 
Twotterwrench
Posts: 1087
Joined: Tue Jan 16, 2001 5:57 pm

RE: Most Stressed Part

Mon Aug 13, 2001 12:34 pm

Rodney, why don't you take your crack pipe and shove it up your.....
 
metroman
Posts: 32
Joined: Wed Apr 18, 2007 9:32 pm

RE: Most Stressed Part

Mon Aug 13, 2001 12:50 pm

I can remember that there was a time when there was some mutual respect between MX and Pilots. Hate to admit it, but I've been in the industry awhile!!

We all used to work together to get the mission done. When an A/C was down for extened MX the Pilots and Flight Attendants use to come in and detail their A/C. Scrubbing headliners, shampooing uphostery and carpets, pulling acoustical windows out to clean inside and out. They had pride, it was their office. In turn, MX would would gather every gripe they had and correct them, along with what ever task that prevoked the A/C to be down in the first place.

Now-a-days you get what Twotterwrench has eluded too. Recently I was called out to an A/C because both engines wouldn't start. Upon gaining access to the cockpit I observed that both power levers were still in the fuel cut off position. I moved them to the start position, and guess what, normal start, thanks for the "Op's Check" Bed Wetter! No wonder you Bed Wetters are so stressed, you embarass your self so many times in front of the paying customers and blame MX for it!!

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