Drawing numbering

General

A sensible solution is to use such a system, which is in use and suitable.

So for numbering ATA-100 system is used without modification. More on the subject, see here (43 mb). Chapters that are used are in this table.

The list of Drawings is here. It is an ODS file, which also includes aircraft mass calculations.

Principle

ATA-100 is a hierarchal numbering system, which contains an aircraft structure and also its use. At first glance, it may look that several numbers are not used, but it has its merits. Mainly all aviation professionals know it!

The hierarchical principle is the following:

Main system..................................... two numbers
-
   Sub system ................................... two numbers
-
     drawing number ........................ four numbers
-
      check number.............................one number
       content description ..................one letter
-
        Revision status ....................... one letter

Example:

27-40-00017
It is from Flight Controls (27), Horizontal Stabilizers (40), and the first drawing of that group (0001). The last 7th is the check number calculated from these, mainly for the future. It makes sure that the drawing number does not have misprints. An error of one number is always revealed. In principle, making a typo in two digits is possible to make a typo and if the second must be correct (1/10 chance to do it). As there are no letters attached, it is a normal/basic drawing. And as that is the end of numbers, it is the original issue of this drawing.

The system does not automatically tell how parts are connected to each other. E.g., drawing 27-40-00025 is not necessary a sub-component of part 27-40-00017. Which parts belong to what assembly or subassembly is listed in the drawing. So those four numbers are just numbers, without any order information. As drawings are made (numbers reserved), the custom is to reserve the assembly number first and parts for it afterward. So in many cases, a higher number is part of an assembly with a lower number, but that is not a rule.

Four first numbers tell always were in the aircraft that part is located.

Drawing may have a designator before these to more designate aircraft type — for example, P8-27-40-00017, which is a part of vertical stabilizer in aircraft type Pik28.

If part or assembly is modified (due mistake or development), and it is a variation of the last part, a revision designator letter is used. Alternatively, a whole new number for that part can be reserved.

ATA-100 System

The mostly used groups for start are:

27 Flight controls
32 Landing gear
53 Fuselage
55 Stabilizers
57 Wings

Algorithm to calculate check number:

Values of single digits are multiplied with 1 and 2, first digit with one, second digit with two, third digit with one, etc. And these are summed together. From this sum, the full tenth is subtracted. The check number is 9 minus the result from the previous calculation. For example, drawing 27-40-00017. How to get that 7? Sum is 2*1+7*2+4*1+0*2+0*1+0*2+0*1+1*2 = 13. The full ten is subtracted from this, i.e.. 13 - 10 = 3 and for the rest 9 - 3 = 7.

Content Description

Drawing numbers have a couple of extensions for some specific (different) drawings. They are used like this:

54-12-12340 is the basic drawing, either a conventional 2D drawing (which you can print on paper) or 3D surface or volume model file of the part/assembly.
54-12-12340S (specification) is a detailed verbal receipt of what the part is like mixing rations for composite lamination. For buying parts, it is the definition of it, alternatives, where this is available, etc.
54-12-12340P (plug, pattern, model) plug used for making mould for composite part.
54-12-12340M (mould, tool) is the tool (mould) for composite part
54-12-12340W (work instruction) is work instructions for a part, like laminating instructions for a composite part, a sequence of work to be done, temperatures, times, tools needed, document.
54-12-12340D (dxf file) is the specific 2D DXF file needed for water jet (or laser) cutting. Eg, frames need this kind of file.
54-12-12340R (recognition) is drawing to recognize a part. For a bought in part (like a model, a mould) normal 3-view drawing including if needed, cut planes, weights, the definition of important surfaces, main dimension so that you can positively identify the part. And they were used for quality control. R-document is not for manufacturing.
54-12-12340-A (hyphen plus a letter) if the drawing has none of the above extensions and a modification is made to the drawing, a hyphen is used. (an example is mod status A for this normal drawing) if the drawing has any of the above extensions, no hyphen is used before modification status (like A in the modification status for a reorganization drawing)
54-12-12340RA if the drawing has any of the above extensions, no hyphen is used before modification status (like A in the modification status for a reorganization drawing)

Revision status

The revision status of the document is done using a letter of the alphabet. English (ACSII) alphabets and order are used. There are 26 alphabets. The original document has no revision status indicator. If more than 26 revision status indicator is needed, a revision to this rule must be done, to define what comes after Z.

so like this (for work instruction):

54-12-12340W is the original drawing
54-12-12340W-A is revision 1
54-12-12340W-B is revision 2 etc.

for basic drawing:

54-12-12340 is the original drawing
54-12-12340-A is first change
54-12-12340-B is second change etc.

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