I had one of the foggiest landing experiences recently and I'm interested if any of you could guess what type of ILS could it be like CAT I,II,IIIA or IIIB?

So the METAR issued 9 minutes before my flights touchdown stated RVR as 100 meters and the METAR issued 21 minutes after the landing stated RVR 750 meters.

The aircraft type is A321NX IndiGo Airlines and Airport VILK the RWY is 27.

Here are the METAR and TAF reports ..it could be wrong but I have just tried to gather them with the information I had so I'd love If someone could decipher it for me please !


(After Landing and Deboarding) SA 02/02/2021 03 : 30 METAR VILK 020330Z 00000KT 0100 R27/0750 FG NSC 11/08 Q1020 BECMG 0150 FG=

(During Approach and Landing) [Touchdown at 03:09] SA 02/02/2021 03 : 00 METAR VILK 020300Z 00000KT 0000 R27/0100 FG VV/// 08/07 Q1019 NOSIG=

(During Holding Pattern) SA 02/02/2021 02 : 30 METAR VILK 020230Z 00000KT 0000 R27/0075 FG VV/// 08/06 Q1019 NOSIG=

Below are the TAF reports for the flight -:

TAF VILK 020200Z 0203/0212 VRB02KT 0050 FG VV/// BECMG 0204/0206 0800 MIFG FG NSC BECMG 0207/0209 32004KT 2000 HZ=

TAF VILK 012300Z 0200/0209 00000KT 0200 FG VV/// BECMG 0204/0206 0800 MIFG FG NSC BECMG 0207/0209 32004KT 2000 HZ=

  • 1
    $\begingroup$ Welcome to aviation.SE! FYI, posting and self-deleting questions with no reason will risk triggering the automated anti-abuse scripts. The best course of action for the future is to edit your posts if you feel that you need to improve them. $\endgroup$
    – Federico
    Mar 4, 2021 at 12:57
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    $\begingroup$ The aircraft type is A321NX IndiGo Airlines and Airport VILK the RWY is 27...I don't know how to properly read METAR and TAF as I'm a beginner and I have learnt how to read a little from websites and but I'd be grateful if I could be helped with this query $\endgroup$
    – Avgeeker
    Mar 4, 2021 at 13:13

1 Answer 1


The 3 METARs all indicate extremely poor visibility. The first one (02:30Z) said:

0000 R27/0075 FG VV///

which means visibility less than 50m (0000), Rwy 27 RVR 75m (R27/0075), fog (FG) and vertical visibility not measured (VV///).

The second METAR (03:00Z) still reports visibility less than 50m, but RVR has improved to 100m. The Airbus A321 is certified for CatIIIB down to RVR of 75m (Airbus getting to grips with CAT II / CAT III operations), so technically an approach would have been allowed before, but note that the METAR is only updated every 30 minutes. The pilots were probably informed by the tower or approach controller about the actual current RVR value.

After landing, the third METAR (03:30Z) already shows improved visibility of 100m and an RVR of 750m, indicating that the fog has started to clear.

Here are the minima for the Cat II/III ILS Rwy 27 approach at VILK (Lucknow):

VILK Rwy 27 ILS Minima

The Cat II is out of the question with a required RVR of 300m (or 350m without autoland in Cat D aircraft). The Cat IIIA would have required at least 175m RVR.

Since the RVR was reported as 100m before landing, the pilots must have prepared for a Cat IIIB ILS approach with autoland. Once the pilots verified that the requirements for a Cat IIIB approach are fulfilled, it does not really matter if the RVR gets a bit better by the time they land, so even if it was 200m at the time of landing, the approach would have been performed with Cat IIIB.

Landings with Cat IIIB seem to be quite common in India according to bangaloreaviation.com:

On the domestic side, only the A320 operators Air India (NACIL-I), GoAir, IndiGo, and Kingfisher have most of their pilots Cat-IIIB certified. Boeing 737 operators Jet Airways, JetLite, and SpiceJet have their pilots certified to the lower Cat-IIIA standard (175 metres runway visibility).

[...] not surprising since the Airbus A320/A319/A321 comes with Cat-IIIB capability built-in, [...]

  • $\begingroup$ I have found the METARs and TAF also of that day..I would love to understand it better from you..should I post it here ? $\endgroup$
    – Avgeeker
    Mar 4, 2021 at 13:31
  • $\begingroup$ Yes, you can edit your question to include them. $\endgroup$
    – Bianfable
    Mar 4, 2021 at 13:31
  • $\begingroup$ Ok thank you sir..can I direct message you here...because I'm new on this website So I don't know much ..I hope you understand..plz forgive if I make any mistakes. $\endgroup$
    – Avgeeker
    Mar 4, 2021 at 13:33
  • $\begingroup$ No, everything is public here so others can learn from it as well. You can have a look at the tour to see how the site works. $\endgroup$
    – Bianfable
    Mar 4, 2021 at 13:34
  • $\begingroup$ I have edited and added the metars of before landing and after landing and also TAF as I was able to gather from a website !..thanks very much for your help ! $\endgroup$
    – Avgeeker
    Mar 4, 2021 at 13:36

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