Engine numbers

[lucavettu]

Since the thread I've started about the same question in the italian forum got locked with no explanation, I'll post my doubt here hoping it's not against any Non-Disclosure Agreement or any FBI secret :confused:.

I know that usually aircraft engines are numbered with 1, 2, 3, 4... starting from the outer left one. My question was: are there manufacturers, airlines, countries, god knows what, that name it in a different way? Maybe swapped, or with any different criteria.

I'm asking because I've always read about this numbering with the word "generally" being written next to it, and I wanted to make it more "sure" in my mind :) Also, I've never read anything about this topic on the doc4444 & co.

[ab33t]

Not that Im aware of

[blueloo]

The 767 the engines are referred to as Left and Right. Not 1 and 2 like a 737.
:}

[dixi188]

The general convention in engineering for numbering is "Left to Right", "Front to back", "Top to Bottom".
I think this is pretty universal, but I expect there are exceptions.

(At least it was this way when I started my apprenticeship in 1969)

The Britten Norman Trislander used to cause some confusion since the middle engine was Number 2, but also got refered to as the "Third Engine", as it was additional to the two in the Islander.

Hope this helps.

[hvogt]

lucavettu,

I have thought about your question a number of times before, and still I cannot answer it either.

Maybe note 3 before 5.1.1 of ICAO Annex 2 Appendix 1 will give you an idea for further research:
Note 3.— The aircraft engines are numbered, for the signalman facing the aircraft, from right to left (i.e. No. 1 engine being the port outer engine).

[lucavettu]

Thanks everybody!

@hvogt: thanks for the annex 2 quote!

[TURIN]

I think on the Trident 3B they were numbered according to the amount of noise they made!:E