Boeing Material Specification BMS 4-20

[CandidateDE]

Gentlemen,

In one of our aircraft modification certification projects we are using some honeycomb sandwich panels that meet boeing material spec BMS 4-20. I have been searching up and down the internet and on Boeings website but I haven't been able to find a copy of this spec or a place where one could buy it. Neither was the composite innovation centre here able to help me. This may be a boeing proprietary spec but it appears to be standard practice for sandwich panel manufacturers to qualify their panels to this and similar boeing specs. Can anyone tell me where to get the spec? I need a referencable copy to substantiate minimum design properties. The other option would be for us to do strength tests but this holds some difficulties since we have no control over the manufacturing of the raw stock panels.

Any help is appreciated.

M.-A.
Aerospace Engineer
Winnipeg

 

[debodine]

I am not Boeing and I have no authority to send you a Boeing document but our organization is an authorized user of some Boeing data. We have a copy of BMS4-20 (at revision L dated 23-OCT-2007) that we obtained from Boeing in the past. The title is "Unidirectional and Woven Graphite and Glass Cloth Faced Aramid Honeycomb Core Floor Panel Stock" so unless it has been superseded or cancelled, I would think Boeing would still have it available to authorized users.

I just searched Product Standards on the MyBoeingFleet website and found it immediately as a still valid specification. When you searched, did you search for BMS 4-20 or BMS4-20? The reason I ask is that the second format (no space between the BMS and the 4) is how Boeing archives their BMS documents and how I found it.

 

[CandidateDE]

hi debodine
thanks for your answer.
I don't have access to that myfleet website you are mentioning. We are a smaller airline and do not operate any boeing aircraft. The project i am working on just uses sandwich panels that happen to be qualified to the boeing standard. The reason we would like to use the standard is so quality control can be handled by the supplyer of the panel and we don't have to do strength tests on every batch. The FARs, in my understanding, really don't have any provisions for using composites that are not either meeting a spec or are individually tested.
Now Transport Canada used to allow the use of manufacturers data sheets for substantiation but in this case the information is ambiguous and i do not feel comfortable using it. Do you know what department at boeing might be in charge of selling such standards?

regards

M.A.

 

[debodine]

I wish I could help but I have never been involved in any actual purchase from Boeing. The specifications we need are provided to us by some process of which I am ignorant and our library department does not really want to give engineering that knowledge. I think they fear I might try to obtain specifications outside their control.