V2500 N1 Vibration Overlimit at Takeoff
 

Query specially directed to Pilots of A320 family with V2500 engines.

There was an inflight shutdown & diversion on an A320 aircraft operated by Airblue in Pakistan about a week earlier. One Fan blade was fractured, ingested into the core destroyed complete engine. Apparently there was high N1 vibration approx 5.2 aircraft units at the time of takeoff run at about 40 knots. This was ignored though the max allowable limit is 5 units. Incident happens at FL30 thirty minutes into the flight.
What is the normal procedure if such an advisory appears during takeoff? ABTO or continue flight as carred out in this incident?

N1 or N2 >= 5 is not a limit, it an an advisory.

One would consult the QRH 2.24 & FCOM 3 3.02.70.

Are vib readouts in the MEL? :confused:

High vibration on takeoff at 40 kts for me would be a stopper. 40 kts is a good time, if any, to get a problem. If I can stop for a simple master caution upto 100 kts then I surely will stop for something as potentially threatening as a high engine vibration. (As long as it is felt as well as indicated on the Vib display)

Wow....ignoring high vibration indication at only 40 knots. But was the 5.2 index seen and commented upon, or only learned of afterwards? If seen at the time then the PIC should be politely forced to attend the 90-day engine MSV to witness first-hand what core engine damage really means.

Don't ask us; ask the ones who are paying the cost. Let's say $5 million, or thereabouts, for a new engine.
How much would a rejected takeoff cost?

Rejected T/O,S in the low and high speed regime are specifically spelt out in my companys FOM.....low speed below 80kts,...high speed above 80kts.....VIB above 5.0 is certainly cause for concern on T/O ,s v,s VIB on engine start for which we have procedures.....

I posed this question to our Chief Check Airmen..... his answer ,the same as mine....totally justified in a rejected T/O......Pull of the Rwy,call MTX,have then download the data......sounds easy I reckon:ouch:

Baret1.....VIB parameters are in "our" MEL

Ok...You return to the gate , the ground engineer look the engine and say everything is fine....
Then you go and have an engine failure...

The end..

Speaking ,as a ground engineer, I would have to do alittle more than look at the fan. Take it out for a power run and justify the return to gate and a reason to furthur inspect the fan or entire engine.

Exactly Firebird..........

Just got to look at the BMid Kegworth incident to see what can happen with engine vibration, complete disintegration of the hot section in that case........

A return to stand would at the least require a run and if vibration confirmed ( ie not an indication problem) then boroscope etc

Definitely a rejected take IF, and that's a big IF, spotted by the crew.

a-3twenty...your a Bus Captain and thats your attitude...WOW!!!:ooh: :(

Are vibration advisories inhibited during takeoff run?

No idea where this is coming from or how it relates to the subject thread:confused:

Kegworth did not start with vibration indications to the crew, it started with no symptoms other than a big bang, followed of course by vibration. As it turned out the bang was from the cold section and not the hot section.

The recommedations regarding vibration response to the crew are to take the time to make your judgements for reaction based on other engine instruments since engine vibration displays by themselves are inherently advisory in nature. As for trobleshooting on the ground the mechanics need to follow recommended procedures based on exoerience.

Check your FCOM vol 1, end of the engines section. THere's a big table that tells you in what flight phases the various messages are inhibited. You may find that it depends on which FWC version you've got.
Although IIRC the flight phase doesn't change until 80 kt...