TSO (Technical Standard Order) and PMA (Parts Manufacturer Approval) - Differences

[AlessandoP]

Good afternoon!
I'm not from USA but my company is under one project to elabarate a new passenger a/c but we are going to apply for FAA TC. I have some questions regarding equipment approval process and I express thanks for any help in advance!
I suggest reviewing on the example:
-There is a a/c manufacturer (Boeing) and he is under a new a/c project ( let's name such a/c as B111 for my case) and would like to get to know much more about certification of an equipment which is intended to be installed on such type desing of a/c. There is a OEM company that has an equipment has been approved acc. to TSO approval process. For example, he is a manufacturer of TCAS II system (TSO C-119). Boeing wants to install such system on its new B111 a/c (not type certified yet) and does not intend to make any changes (functional, design) into such already TSO approved system. Then OEM organization supply TCAS II accompanying with TSO Authorization Letter, DDP , maintenance and compliance doc's. My first question is : Will such volume of doc's enough for FAA (to permit to install TCAS on board for ground/flight a/c tests) ?

The second question) please forgive me for my insolence! - Now look at such project from the OEM side. I'm OEM (manufacturer of TCAS II). As no needs to make any changes to TCAS system approved design (case #1 ) I just compile necessary documentation in acc. with TSO and sends it to Boeing?! Am I right?

The third question is: when shall I as OEM company use PMA process or TSO process within my example with new B111 a/c.

Thank you for your help!

 

[andygr]

Re: Difference between TSO and PMA

My first question is : Will such volume of doc's enough for FAA (to permit to install TCAS on board for ground/flight a/c tests) ?

For the aircraft certification process the TCAS should be covered under a conformity project covering any differances between a TSO conforming part and one that has been altered to cover tesing and monitoring. If the configuration is fully compliant with the TSO data that you could just use the 8130-3 tag issued for the part under the TSO.

TSO's approval's can be given before AC type certification.

For the PMA if you as TSO holder wanted to allow component part suppliers to be able to send parts into the aftermarket you could suport their application for PMA against your design data. DO NOT ever send a part marked PMA to Boeing they will be quick to tell you this is not allowed.

 

[AlessandoP]

Re: TSO (Technical Standard Order) and PMA (Parts Manufacturer Approval) - Difference

Andygr! Thank you for the help!
As I knew, if your TSO approved configuration (including functional features) in acc. with TSO C-199a and the manufacturer doesnt add any additional requirements to TCASII then that equipment is issued with Airwothiness tag 8130 and will take a part within a/c to perform a/c ground and flight tests?!
But if a/c manufacturer want a TCAS with different form-factor, for instance 4 MCU instead of 6 MCU then TCAS manufacturer will apply for a new TSO authorisation with the diffrence form-factor, because I think the changing a form-factor is a major change.
Is it a rught?

 

[andygr]

Re: TSO (Technical Standard Order) and PMA (Parts Manufacturer Approval) - Difference

But if a/c manufacturer want a TCAS with different form-factor, for instance 4 MCU instead of 6 MCU then TCAS manufacturer will apply for a new TSO authorisation with the diffrence form-factor, because I think the changing a form-factor is a major change.
Is it a rught?

As you suspect any changes made to the originaly approved type design will require approval by the FAA.

 

[AlessandoP]

Re: TSO (Technical Standard Order) and PMA (Parts Manufacturer Approval) - Difference

And what about FAA PMA)
In what cases does TCAS manufacturer have to use PMA approval process?! Could you give me an example of such case

Best regards!

 

[rdh63]

Re: TSO (Technical Standard Order) and PMA (Parts Manufacturer Approval) - Difference

And what about FAA PMA)
In what cases does TCAS manufacturer have to use PMA approval process?! Could you give me an example of such case

Best regards!

A PMA is usually only used by part manufacturers when the part is not designed to a TSO.

14 CFR 21.305 states that parts may be approved (a) under a PMA, (b) under a TSO, or (c) in conjunction with type certification procedures for a product.

An example is a replacement seat rail. There is no TSO for the part, so the manufacturer would need a PMA to sell the rail.

In your case, electronic equipment is almost always produced to a TSO.

A TSO approval is given only after the part is tested and meets the TSO requirements. I have seen a few elctrical components that state they are manufactured to TSO-xxx, but are not actually TSO approved by the FAA.