CAT2 minima (RVR)

[CW247]

In EASA land..

CAT2 lowest DH is 100ft and lowest RVR is 350m. However, according to EASA Ops, "an RVR of 300 may be used for a category D aircraft conducting an auto-land".

To me that sounds like two conditions that need to be met if an RVR of 300m exists at the time of approach. You must be a category D (that's actually not that many aircraft!) AND on the day, be capable of an auto-land.
However, my last 2 interviewers were perplexed by this relatively complex answer and were simply expecting to hear 100ft/300m as the answer to the question "what is the lowest minima for a CAT2 approach. Interestingly, one airline had a mixed fleet of mixed ages, the other 100% A320 CEOs. They should be exposed to this complication.

It's left me questioning myself, but I'm gonna go out on a limb and say I'm correct and that most pilots are unaware of the qualifying criteria behind the 300m RVR. What's your experience?

Second question, I've seen people use ranges instead of the "less than" language mentioned in EASA OPS like the example below. Is that valid? If no, then trainers everywhere need to address this incorrect thinking. If yes, the language used by EASA is pathetically bad.


https://cimg3.ibsrv.net/gimg/pprune.org-vbulletin/598x395/capture_518f1616c8f9a11d11b578644c86b391d7cfebcc.jpg
https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/233x218/2_f050ec796b3ec012e2916a0785eb52f54d57d712.jpg

[deltahotel]

No idea of the regs on this but a very quick scan through the charts at airfields in various EU countries show minima of 300R for Cat C and D ac.

[FlightDetent]

CAT II required RVR is 300 m.

If you would need to do MANUAL landing for CAT II on a D category aircraft, it is increased to 350 m.

For category C there is no such additive.

A32x pilots are usually not trained to CAT II manual landing ops, hence it should not be available to them anyways. Always check LIM for autoland, some machines only have 2500 pressure altitude.

https://store.icao.int/en/manual-of-all-weather-operations-doc-9365 this one is quite useful for thorough understanding.

BTW: DH needs to be derived from the aircraft geometry based on the required visual segment. Further reading from G2G CATII/III.


https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/841x817/snippet_8dfa1f5180a8af3aae830cae8b3c372f43d78e4e.png

[CW247]

FD, your numbers are the other way around. Please check.

[Jonty]

The numbers I have for Cat 2 approaches are for Cat A/B/C aircraft DH 100ft and RVR 300m. For Cat D aircraft it’s DH 100ft and RVR 350m. For Cat D aircraft the RVR may be reduced to 300m if they conduct an auto land.

For the A321 that’s a Cat D aircraft, planed Cat2 manual landings are not authorised, so the 300m would apply in this case.

[FlightDetent]

FD, your numbers are the other way around. Please check.Alternatively your understanding is the other way around. 👀

[safetypee]

FD, Cat II minima :ok:
As per ICAO doc 9365 Manual of all weather operations.
EASA - ongoing review of AWO ?

Re #3, is the interpretation of the diagram as showing an RVR of 217m equating to a SVR of 250m. If so minor confusion as RVR only given in 10s
Although geometrically accurate, it only applies at a single instant; DH=100ft. Operationally the pilot needs to see the required visual segment above DH with sufficient time to make a decision (2 sec ~ +20 ft at 10ft/sec), which would imply a higher RVR, hence 300m minima.

Also, note that many fogs, particularly in Cat II, do not have a linear relationship between SVR and RVR, e.g after acquiring the required vis segment it ‘opens’ rapidly with decreasing altitude, like exiting very low cloud - tight decision, easy landing.
Alternatively a ‘closing’ segment where the vis segment reduces with decreasing altitude like entering thicker ground fog - easier decision, but could be difficult for manual landing, yet for the same reported RVR.

ICAO doc 9365 e reader @ https://elibrary.icao.int/reader/229745/&returnUrl%3DaHR0cHM6Ly9lbGlicmFyeS5pY2FvLmludC9leHBsb3JlO3Nl YXJjaFRleHQ9ZG9jJTIwOTM2NSUyMCVFMiU4MCU5NCUyMG1hbnVhbCUyMG9m JTIwYWxsLXdlYXRoZXIlMjBvcGVyYXRpb25zO3BocmFzZU1hdGNoPTAvcHJv ZHVjdC1kZXRhaWxzLzIyOTc0NQ%3D%3D?productType=ebook

[CW247]

FD, may be I'm being thick (it's possible), but please spell it out for me. The below from Skybrary clearly shows that the default lowest RVR for a CAT 2 approach is 350m. Then there's a note to say that 300m is achievable for CAT D a/c performing autoland. You have stated the opposite.
https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/781x334/fa_e69c84a387bc63b797d9582a1791c0ef204b4dc1.jpg


My second question (open to anyone) is, why does AMC5 SPA.LVO.100 (the official EASA reference) state that the lowest DH for CAT 3A is "Less than 100"...
https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/959x1083/whatsapp_image_2022_03_24_at_10_43_58_85ae0a8e1b7747f3a11cdd 974afae41b62f69781.jpeg
But virtually every airline training department teaches that it's 50ft? The below is from my company's training document (they're not the only ones). And before you say it, this is not about company minima. They are claiming it's regulation. My question, which is it? Less than 100ft (implying all the way from 100-0ft) or only down to 50ft?

https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/961x134/fa_6533faa9c2c61ce90e8863ee4c221fed8ca5e918.jpg

[FlightDetent]

There are four people referencing 6 sources saying it's 300, it's an honour you chose me to search the regs for you.

EASA AirOPS
-ANNEX V Specific Approvals [Part-SPA]
--SUBPART E Low Visibility Operations (LVO)
---SPA.LVO.100 Low visibility operations (c) Standard Category II /CAT II/ Operation

is further explained in AMC4 SPA.LVO.100 Low visibility operations

CAT II AND OTS CAT II OPERATIONS
(a) For CAT II and other than Standard Category II (OTS CAT II) operations the following provisions should apply:
-(4) The lowest RVR minima to be used are specified:
--(i) for CAT II operations in Table 3

Let's have a look:


https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/783x438/snippetcatii_9d0fde60ac526006b3682d69bbd7ce6871db4a65.png

I find it observation worthy you quoted AMC5 about CAT III yet managed to miss the table above located on the same page.

https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/617x852/fullpage_053f4832c20d340763a176a4e088be64b9772cff.jpg

[FlightDetent]

As your screenshot shows Appendix to JAR-OPS 1.430 (BTW not say if 'old' or 'new' which was kind of important then), to avoid confusion one more snippet for convenience:


https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/723x451/1430_e9a3ef9f4ce33aea39c10562711bbc904d833298.png
Ref: JAR-OPS 1 Subpart E JAR–OPS 1.430 Aerodrome Operating Minima – General
from Amendment 3 to the regulation dated 01 DEC 2001 // means it's the 'old' version //

[dixi188]

As to the original question, "What is the lowest minima for a Cat II approach?, the answer is 100ft/300m.
For an interview I was told to always keep the answer as simple as possible and not to dig a hole. If the panel want more they will ask for it.

[CW247]

FD, thanks for the patience. I don't know where it all went wrong with my observation! Maybe it's all that hay I was busy collecting whilst not flying for 2 years. :{
Any clues regarding the second question? :E

[safetypee]

247, Q2, great confusion in AWO operations.

The original ICAO defined operational categories using DH and RVR have been eroded. First by the auto system integrity required by certification (CS-AWO; also CS 25); this is the aircraft - system capability which generally specifies min DH, sometimes rollout. More recently alternative equipments other than autopilots are used, also claiming credit for pilot manual control and training (OPS requirements); then depending on ground facilities, navigation source amongst other things, ….

Generally if ‘it’ can be proven to be safe then it can be used (can a human ever be sufficiently safe ?).

Thus less than 100ft DH has to encompass many systems and capabilities; however there is a step change in CS-AWO, 50ft, primarily integrity, combined with visual requirements - pilot cannot see enough to continue with a manual landing. Note; there are exceptions (beware exceptions) in RVR, e.g. 50 ft DH 150m RVR with ‘super’ fail passive autoland (as defined in the small print), allows manual reversion to land after AP failure in RVR above 200, but with RVR less than 200, a GA must be flown (e.g. AVRO RJ by modification and national approval).

[CW247]

Wonderful.

Thanks for this. What a sorry state of affairs this become.