View Full Version : Air Directive Information sought

07-31-2009, 07:16 AM
Hi all.

I am looking for information on what exactly ADs (Air Directives), SBs (Service Bullitins), SIL (Service Information Letters) and EO (Engineering Orders) are and how they affect aircraft maintenance.

This is to help me with my Job and isn't cockpit related, but I thought there may be some engineers amongst us that could describe these to me in a Civil Aviation context.

I have to go to an airline next week and learn as much about their line and base maintenance planning as possible so I can design software for it, my boss would also like AD,SB,SIL and EO info to be collected as no one in our company knows much about it. Anything you can give me will be very useful as Google has nothing!

Thanks, Tom.

08-05-2009, 12:45 PM

Did you try the CAA?

I recall a while ago trawling through loads of interesting stuff at www.caa.co.uk

Geremy Britton
08-05-2009, 01:34 PM
As far as my knowledge goes:

An Air Directive is an order. Generally issued by the CAA, NTSB, and other commercial aviation safety teams to make a compulsory change to their aircraft. This is generally for safety reasons, as a result of an accident, experiement or imminent problem. The air directive, if i remember rightly, means all aircraft in the company fleet can if the reason warrants have the change/inspection carried out. This can generally cost the airline a lot of time, and money.

There is also such thing as an 'airworthyness directive' which instructs the owner to undergo a procedure to check the plane is acceptable to fly under standard law.

Sorry, i can't help you out with the others. And you're right.. Google hasn't yeilded any results for me for the other's either.

Hope that helps very slightly.

08-05-2009, 02:15 PM

Here's a link to the US FAA Regulatory and Guidance Library which may be of some use to you.


08-05-2009, 04:57 PM

Google is your friend


For examples of each see below. Unfortunately it is very difficult to obtain SBs, SILs or EO's for commercial aircraft types, unless you have a subscription to the manufacturers technical publication service.

EASA AD's http://ad.easa.europa.eu/

Service Bulletins (Teledyne Continental as an example) http://tcmlink.com/servicebulletins.cfm

Service Information Letters (Avionics as an example) http://www.sandel.com/SN3500_EHSI_sup_sb.php

Engineering Orders (Diamond Aircraft as an example) http://www.diamond-air.at/stc.html

Hope this is of some help.

08-06-2009, 01:35 AM
Hi all.

I am currently at an airline and we went through AD and SB evaluation yesterday.

ADs are Sooo complicated, and can take litteraly days to go through (some are 80Mb in size!) and calculate what you need to do for your aircraft.

Your links and documents have been useful so thankyou all very much! : )