First time poster so go easy on me !! I've been reading the forums for a good while now and like what I've seen so here I am !
Anyway.. being a big fan of anything selcal-related I have been trying to find out for a longggggg time now why BMA/BMIBaby's 737 rego G-ODSK is fitted with a strange out-of-sequence selcal code that actually works!?
The code is JR-ER. This goes against the ARINC 'law' that dictates selcal letters can only be used once. I understand that this is because when the letters are converted into RF 'tones' and sent out by the ground station the selcal receiver on the aircraft would not be able to successfully receive the selcal because each 'tone' (JR and ER) would be too 'close' for the receiver to distinguish. However, on the few times I have heard this aircraft ask Stockholm Radio LDOC for a selcal check the crew have always confirmed a successful check.
Can anyone tell me why ARINC issued this out-of-sequence code and/or maybe tell me why more haven't been issued given the success of this example above and also considering the number of available selcal codes is nearly at crisis point already ?
Thanks & cheers,