Bangladesh has decided to establish an ADIZ over the entire country, including a massive chunk of airspace off their south coastline that actually extends over much of the adjoining Indian VECF/Kolkata FIR.
Aircraft intending to fly into, through, or within this new Bangladesh ADIZ must now obtain an ADC (Air Defence Clearance) number beforehand. Just file your flight plan, and they will send this to you by AFTN. Make sure you write it down – as they will ask you for it on HF before you enter their airspace.
If you don’t have AFTN access, you can get the number by calling +880-2890-1081 or emailing email@example.com
The authorities in Bangladesh have released a scary sounding AIC on all this, which you can read in full here. What they fail to mention there, but have published by Notam, is that there are actually a bunch of airways over the ocean (P646, N895, M770, L524 and W112) where you won’t have to get this ADC number, unless you deviate towards the landmass of Bangladesh.
As the Notam clarifies:
A0032/18 NOTAMN Q) VGFR/QXXXX/IV/BO/AE/000/999/ A) VGFR B) 1802010001 C) PERM E) THE FLW AMDT/UPDATES ARE BROUGHT TO THE AIP-SUPP 01/2018: 1. ACFT INTENDING TO OPR INTO, THROUGH OR WI BANGLADESH ADIZ SHALL OBTAIN ADC NR FM THE FLW CONTACT DETAILS. TELEPHE: +880 2 8901081 FAX : +880 2 8901081 E- MAIL: ADNC AT THE RATE OF BAF.MIL.BD AFTN : VGHSZQZX 2. FLT OPR ON ATS RTE P646, N895, M770, L524 AND W112 SHALL NOT REQUIRED TO OBTAIN ADC NR UNLESS DEVIATED TOWARDS THE LAND MASS OF BANGLADESH. 3. GUARD FREQ. 121.50 MHZ SHALL NOT BE USED TO CTC THE AIR DEFENCE UNIT. 4. ARTICLE 'L' IN THE PROCEDURES FOR AIR DEFENCE CLEARANCE IN THE AIP-SUPP SHALL BE TREATED AS CNLD. 5. FOR THE TIME BEING DOMESTIC FLT AND FLT OF STATE ACFT AND GENERAL AVIATION ACFT OF BANGLADESH SHALL NOT BE REQUIRED TO OBTAIN ADC NUMBER.
So you won’t need an ADC number on those airways, but for everywhere else in that big red ice-pick-shaped chunk of airspace, you’ll need to get authorisation. As the Bangladesh AIS office politely warn in their AIC: “Aircraft flying without a valid ADC number or failing to comply with any restriction or deviating from flight plan will be liable to interception by Bangladesh Air Force Interceptor aircraft according to ICAO Standard Interception Procedure.”