Fuelling the 135.
SB EC135-28-005
All models S/N 0005 up to and including 0400.
During an inspection on a helicopter it was found that the hook and pile tape (Velcro) for tank attachment to the floor had become partly detached. As a consequence this can lead to a reduction in the effective usable tank volume or to a longer refuelling time (read blowback) being necessary for the filling of the tank to its full capacity.
Procedure: Defuel and remove equipment plates and inspect ceiling of the tank. If the velcro has become detached badly, you have to remove the tank, replace the existing Velcro and fit additional as per SB.
Compliance: If it is not possible to fill the normal fuel quantity stated in Section 2 of the RFM, or it takes longer than it used to, to completely fill to the full quantity in the tank, the attachments of the tank lower shell are to be inspected at the next removal of the equipment plates.
Manpower: Fitting of each hook and pile tape 0.5 man hours. (There are 25 of them - 12.5 hours) Strangely no mention of the man hours required to remove each tank so you can change them and subsequent leak check. This requires removal of the floor sections! At a guess this would be a 3-4 dayer.
I think a lawyer must write these SB's. Too bad if you if you have time against you and need all the fuel available.
The blowback is the air pockets formed around where the tank has become detached.
More info: One of the reasons for this and other mods subsequent to SN 249 were issues between pre-Production and Production aircraft. Some fuel capacity was lost due to a few subtleties and certain customers made a point of it!
Last edited by RVDT; 28th Aug 2008 at 17:33.
Reason: More info