temps

lo flyer · Post by **lo flyer** » Sat Jan 08, 2005 9:03 am

What are the consequences of over-temping a turbine?

TOGA Descent · Post by **TOGA Descent** » Sat Jan 08, 2005 9:13 am

In the worst of scenarios, it's much like putting a Blow Torch to a Beer Tin!

Seriously though. If you did, was it a company limit? Or the manufactures limit? Either way, the most important question - Did you "snag" the aircraft afterwards. You wouldn't want the guy before you to do it, and not tell YOU.

The only thing you can do, is report it to your maintenance department. In most cases, if the over-temp was momentary, the engine will be fine. But, your maintenance folks are the only people who can make this conclusion.

Flying Low · Post by **Flying Low** » Sat Jan 08, 2005 9:13 am

Long term payroll deductions?

Cat Driver · Post by **Cat Driver** » Sat Jan 08, 2005 9:14 am

Did you?

lo flyer · Post by **lo flyer** » Sat Jan 08, 2005 9:17 am

No, I didn't over-temp but I have heard stories recently of people who did. You know, the whole friend of a friend thing.[/list]

TOGA Descent · Post by **TOGA Descent** » Sat Jan 08, 2005 9:21 am

lo flyer wrote:No, I didn't over-temp but I have heard stories recently of people who did. You know, the whole friend of a friend thing.[/list]

Friends, don't let friends, fly compromised aircraft!

lo flyer · Post by **lo flyer** » Sat Jan 08, 2005 9:28 am

TOGA, you are completely right. I wouldn't (or I would at least try not to) let that happen. I am still just a piston guy so I dont really have the knowledge of turbines down yet. Just curious though, what does it actually do to the turbine......Is it similar to over-boosting?

TOGA Descent · Post by **TOGA Descent** » Sat Jan 08, 2005 9:36 am

Like I mentioned earlier, in the WORST case, imagine putting a welding torch to a beer tin, and you have the general picture.

greenwich · Post by **greenwich** » Sat Jan 08, 2005 10:31 am

'lo flyer':

Toga's right...its got to be reported. I know people who have over-torqued and over-temped engines and they didn't automatically lose their jobs.

Most Turbines come with some sort of a scale based on time...that the longer (in seconds) that you are over the manufacturers limits (temp or torque) the more serious it is, and thus the greater inspection maintenance needs to do!

Worst case scenario it that maintenance will have to remove the engine and send it away to be checked or overhauled. This can run into the US$ six-figure range quickly!!

Bottom line: As scared as one is to report it, it has to be reported! You could kill a friend who takes the plane up the next day!

G

Mitch Cronin · Post by **Mitch Cronin** » Sat Jan 08, 2005 10:35 am

TOGA is quite right... worst case scenario is the turbine blades can be melted down to little wee stubs. - or it could lead to a failure of a sudden and rather ugly nature.

In a lesser severity, it shortens the life expectancy of the engine. Rotational speeds at temperature stress the components... add too much temp and the effect of the rotational speeds is likewise greater.

Most (if not all?) turbine engine manufacturers will have time limits for overtemping and the cumulative time at a given overtemp must be recorded and monitored... (beyond certain limits the engine should be removed) with special inspections at various levels... It is very important that the max temp, and the time at that temp is recorded for maintenance purposes.

A small degree of overtemp for short time periods can usually be handled just fine, but the cumulative effect will still likely have an impact on the turbine's life limit.

Surely all recent large "NG" aircraft will do their own recording of such events, but older and smaller turbine powered birds -and their occupants! -are dependant on honest reporting from those who operate them.... If you give a damn at all about the next guys to fly the machine, just as if you'd oversped the airframe, you need to report it.

Edit: Sorry Greenwich, you obviously type faster than I do.

greenwich · Post by **greenwich** » Sat Jan 08, 2005 11:31 am

'griffon':

No problemo...good points!

G

Vickers vanguard · Post by **Vickers vanguard** » Sat Jan 08, 2005 2:15 pm

saw that once......1999, B747-400 Atlas Air operating for China Airlines. RB211-535, flight crew didn't have to tell anybody.......the EGT indication on EICAS goes and stay RED when you overtemp the engines..even if you remove electrical power(non volatile memory).
Now with the autostart on airbus and boeing....the protection is always there unless there's a fault in the FADEC logic.

twinpratts · Post by **twinpratts** » Sat Jan 08, 2005 2:47 pm

I heard the (turbine) blade tips can rub on the outer casing of the Turbine...causing scoring along the inside of the engine

RJ · Post by RJ » Sat Jan 08, 2005 6:28 pm

Had an engine failure last year...P&W says it was due to overtemping...this was of course over a long period of time but it goes to show if you abuse it you lose it.