ICAO – N-Number Converter

Script converting ICAO addresses to N-Numbers (Tail Numbers) and reciprocally. Only works for United States aircraft registrations.

Using the converter

Requirements

• Python 3.x
• Nothing else =)

Install

Using pip install

pip install icao_nnumber_converter_us

Usage of the n_to_icao and icao_to_n functions. Note that both functions return None on invalid input.

python3
>>> from icao_nnumber_converter_us import n_to_icao, icao_to_n
>>> n_to_icao("N12345")
'a061d9'
>>> icao_to_n("abcdef")
'N86QU'

Or simply clone the repo, and start converting.

git clone https://github.com/guillaumemichel/icao-nnumber_converter.git
cd icao-nnumber_converter

Convert N-Number to ICAO address

> python3 convert.py N12345
a061d9

Convert ICAO address to N-Number

> python3 convert.py abcdef
N86QU

Format & Mapping

ICAO addresses are hexadecimal values of length 6. US registered ICAO addresses start with 'a'. N-Numbers, or Tail Numbers, are alphanumerical strings at most 6 characters long. US registered Tail Numbers start with 'N' (that's why they are called N-Number, yes!). Their format is as defined below.

There is a direct sequential mapping from US ICAO addresses to N-Number, from a00001 for N1 to adf7c7 for N99999. The mapping is somewhat intuitive, but not convenient to implement.

The mapping goes like this:

ICAO address	N-Number
a00001	N1
a00002	N1A
a00003	N1AA
a00004	N1AB
a00005	N1AC
...	...
a0001a	N1AZ
a0001b	N1B
a0001c	N1BA
a0001d	N1BB
...	...
a00259	N1ZZ
a0025a	N10
a0025b	N10A
a0025c	N10AA
a0025d	N10AB
...	...
a004b2	N10ZZ
a004b3	N100
a004b4	N100A
a004b5	N100AA
a004b6	N100AB
...	...
a0070b	N100ZZ
a0070c	N1000
a0070d	N1000A
a0070e	N1000B
...	...
a00724	N1000Z
a00725	N10000
a00726	N10001
a00727	N10002
...	...
a0072e	N10009
a0072f	N1001
a00730	N1001A
a00731	N1001B
...	...
a00751	N10019
a00752	N1002
...	...
a00869	N10099
a0086a	N101
a0086b	N101A
a0086c	N101AA
...	...
a00c20	N10199
a00c21	N102
a00c22	N102A
...	...
a029d8	N10999
a029d9	N11
a029da	N11A
a029db	N11AA
...	...
a05157	N11999
a05158	N12
...	...
a18d4f	N19999
a18d50	N2
a18d51	N2A
a18d52	N2AA
...	...
a31a9e	N29999
a31a9f	N3
...	...
ac6a79	N9
ac6a7a	N9A
...	...
adf7c7	N99999

Useful links:

• This forum post.
• FAA N-Number Inquiry