Hi,

Does anyone know how to interprete the last three characters of an aircraft model ?

Eg: Boeing 747-412 What is '412' ?
I know what a 747-400 is, but is the last two some airline specific codes ?

You're on the right track they are known as "Customer Codes" and represent the build configuaration of that airline's fleet.

412 is a -400 series of SQ, Singapore Ailines.

http://www.airlinecodes.co.uk/boeing.asp

Phreegreens hit it dead on.

This system (which is unique to Boeing) only identifies the initial purchaser; aircraft retain the code throughout their life. Therefore airlines with secondhand Boeings in their fleet can have a range of suffix codes although the aircraft may be identically fitted out.

Conversely the system does not handle major differences an airline may have. British Airways has two major groups of 777s, with engines by different manufacturers, different maximum weights, seating configurations, etc, but they are all 777-236s. All BA Boeings have model numbers ending in -36.

The system started in 1958 with the first 707s. Pan Am were the first orderer and got assigned 707-121. Boeing then numbered the sufixes from 21 upwards as new customers came along, and so the progression of the system really represents the sequence in which airlines ordered jets from them over 40 years ago. BA (actually their BOAC predecessor) were thus the 16th airline to order Boeing jets. They got up to 99 by the end of the 1960s, then used 01 to 19, then moved on to one letter-one number combinations. Singapore Airlines was founded in 1971 when the old Malaysia-Singapore Airlines (MSA) was broken up, and 12 was the next suffix available when they placed their first order.

The model number thing got me thinking...... since I fly Spirit a lot, I seem to be on the MD-80,81,82 often-too often. Anybody have any guesses on how old these birds are? So glad they have the the new Airbus 321.......Its hard to read the data plate on the front door opening, kinda small, and don't want them wondering what I'm looking at, but I swear I thought I saw "83" on my last trip.

No need to guess. Just do this:-

• [*]
• [*]
• [*]

This will return all the active aircraft MD-80 series aircraft that fly or have flown with Spirit. You'll also get a potted history of each aircraft, most of them having their first delivery date when new. (Obviously, ignore the ones that are now flying for other airlines.)

Use this link:

Spirit Airlines Fleet

If you want to see the history of an aircraft, click on the number in the "cn" (constructiuon number) of the aircraft in question. This gives you delivery date, previous owners and previous registrations.

Such as:

N800NK

One aircraft that has been around the block a few times....

Thank you both very much. Thoroughly enjoyed those sites and will be looking at the next tail number I fly!