This is a really interesting question that we are asked a lot, but there isn’t a straight yes or no answer.
For some organisations the cost (time and financial) of maintaining 2 ISO standards and paying the cost of 2 different certifications can be a big concern.
AS9100:2016 Rev D includes the entire ISO 9001:2015, but adds specific Aerospace/Defence clauses/requirements. It does not remove any of the ISO 9001 clauses, plus they are really nice to you and highlight all additional clauses in bold text so it’s easy to see.
An example of this is clause 7.3 Awareness. In ISO 9001:2015 there are 3 sub clauses a – d, AS9100D:2016 takes these and then adds a further 4 sub clauses e – h.
Based on this, in theory why would you need separate certification for ISO 9001 when it is included in AS9100?
People who don’t work in the ISO world day-in-day out won’t realise this, therefore when they ask you if you have ISO 9001, you would have to explain “don’t worry we have AS9100 so it’s included…….”, but they may not understand, potentially leading to lost work as you don’t meet their supplier requirements (I have personally seen this many times over the years).
(In the UK) There is something that you can do about this. If you achieve certification to AS9100D:2016, most certifications bodies will allow you to pay a nominal fee and issue you with a certificate for ISO 9001:2015 as well. After all their AS9100 audit covered all of the clauses of ISO 9001. If your certification body will not issue the certificate, please remember that certification bodies are just a supplier (great article here), and it is a very competitive market!