MD11 CF6 N2 Vibs limits check list

[Carbon Fibre]

MD11 CF6 N2 Vibs limits check list
Hi everyone, I am an engineer (actually a tech services guy unfamiliar with this type).

Just wondering if someone could provide me with the N2 Vibration limits for the CF6 powerplant for the MD11 by way of the checklist (and attach a copy if possible) neccesary for an exceedance or approaching exceedance levels. Also to my engineering colleagues a copy of the vibration limits in the maintenance manual ( and attach a copy if possible).

Please be garaunteed that no one is going to get into trouble I am just having issues with the engine shop!

BRGDS

Carbon Fibre

[Carbon Fibre]

I thought we would have few guys licenced to fly and fix the MD11? any help would be appreciated

[Tinwacker]

Please be garaunteed that no one is going to get into trouble I am just having issues with the engine shop!

So what issues have you got with the engine shop that you require PPRUNE to solve ????

If this engine had passed the exceedance level then I assume the Line engineers had to remove the engine for the engine shop to do an internal strip and detailed investigation.

actually a tech services guy unfamiliar with this type

So the engine shop has told you something that you are choosing not to accept perhaps ??

I am sure the engine shop has suitable type manuals for you to get any detailed information. To then discuss and demonstrate with you what is done for the engine vibration values given.

I of course assume that the aircraft wiring was found satisfactory and that the defect discussed is within the engine ??

Or is that the problem. The engine shop have found nothing wrong....

TW

[mono]

These figs are for the 767 CF6 80C. Sorry I don't have access to the MD-11 AMM.

Note the statement at the top. There are no in flight limits according to the AMM (FOR THE 767) I assume this is because there would most likely be other engine parameters that would require pilot attention/action at the same time as a high vibration event.

C_A_U_T_I_O_N_: THESE GUIDELINES APPLY ONLY TO GROUND TEST OF ENGINES
DURING MAINTENANCE AND DO NOT APPLY TO FLIGHT OPERATIONS.
(1) The maximum permitted vibration for continuous operation is as
follows:
FAN - 4.0 units (8.0 mil double amplitude)
LPT - 4.0 units (8.0 mil double amplitude)
N2 - 4.0 units (2.0 inches/second (peak))
BB - 4.0 units (1.68 inches/second (RMS))
(a) If the vibration is more than the specified limit, correct the
high vibration.
S 862-108-H00
(2) Sudden shifts of 1.0 unit on scale should be investigated.

I would expect an engine relaesed from the shop to have MUCH lower values than these.

Cheers.

Hope this helps.

[Orangputi]

Hi Carbon Fibre

I am also familiar with the 767 just not too sure of the MD11 engine airframe interface. However, a mate who works on the freighters indicated that it is 2.5 units for the mm and you get an amber caution in the cockpit at 4.0 units (N2 )vibs.