View Full Version : FMC coding of Q Type approach // AINC 424 stuff

14th Jul 2015, 19:34
Unfortunately the Bluecoat-mailinglist is deceased so I try this with you experts out there.

Following my complaint over coding of some procedures I became privy to mails between coding vendor and Honeywell in which the term "Q Type approaches" was used.

Now, what is a Q Type approach ?

17th Jul 2015, 11:43
Now, what is a Q Type approach ?

NDB with DME. 'N' is NDB. This is not Honeywell (or Smiths) but an ARINC standard.

18th Jul 2015, 21:16
Hmmmm.. the term popped up in connection with a whole lotta approaches - mostly RNAV.

20th Jul 2015, 02:49
Interesting. Could it be you are looking at a conversation/list involving the incoming new order?

I know in the states, there are hundreds of airports, some quite large, that are on the FAA's ground-based NAVAID chopping block. They are VOR, VOR/DME, NDB, and NDB/DME (NPA) approach types and are (or will be) approved for RNAV procedures (PA).

I understand there are a higher percentage of airports served in European airspace by NDB's compared to the US. The retention of older ground-based NAVAIDs being driven by mainly political reasons - the mistrust of the US military-run GPS constellations. With Galileo coming in 2016, perhaps Eurocontrol is on the same path as the FAA.

West Coast
20th Jul 2015, 05:22
Another retention reason is the RAA's politicking on behalf of single FMS and no FMS equipped aircraft operators. The FAA is very clear in opspec B034 what a single FMS equipped aircraft limitations are. They have been fairly tight with interpretation under AC-108 what can be flown with a NAVAID outage, hence the RAA's pushing the issue of retention.

20th Jul 2015, 06:16
vapilot2004, no new order here but my complaint to data vendor and Honeywell that a number of arrivals did not show / were available for selection on the CDU.

West Coast, I have no idea who RAA are but we do run dual FMS in daily ops. AC-108 seems to be about security/screening/etc ! ?

20th Jul 2015, 06:20
WC, well that all makes sense, if by RAA you mean the airline group.

The ongoing phase out of ground-based NAVAIDs has strong potential to affect marginally equipped aircraft operations when the sun is not shining. As the NEXT-GEN system begins to take shape, shutting down all but 30 airport-based VORs is both cost-saving and a forced requirement towards RNP goals.

One concern beyond protecting the 'little guys' is that of redundancy - putting all of our NAV eggs into one GPS basket doesn't seem like a good idea.

20th Jul 2015, 06:24
D2D, is it possible those airports that have gone missing are (RNAV approaches aside of course) NPA-only equipped?

West Coast
20th Jul 2015, 07:31
D2D, AC-90-108, to answer your question. Unfortunately don't think it contains the answer you're looking for, more towards the retention of NAVAID tangent.


Yes, Regional Airline Association. They are working hard to makeup for poor decisions made in the 90s and beyond wrt how thier carriers equipped thier aircraft. The price of admission to next gen is among other things having dual FMS equipped aircraft.

20th Jul 2015, 08:07
The procedures are current and published as per the AIP and are in the database without question.

My complaint was that a number of arrivals was not selectable as they did not show on the CDU - absolutely nothing to do with ground facilities.

20th Jul 2015, 09:31
Regarding the regionals - I think I might understand how they got there - and it probably wasn't all profit and short-sightedness. Perhaps it was more along the lines of: 'Why install equipment and/or upgrade to aircraft capable of doing things we don't currently need to do?'

Am I to understand that while we opened with approach types, (ILS, VOR/DME, RNAV is what I assumed) it seems your issue with Honeywell's database package is more about arrivals, as in published STARS? Or is it possible there is a language difference between us? If so, I apologize.

Meanwhile, I can vouch for the correct nomenclature and definition of Q-Type approaches used by Honeywell as being NDB with DME per ARINC and if we are talking about airport approaches, I would suggest getting Aterpster in on this discussion - if anyone here knows about approach data and design, it is he.

West Coast
20th Jul 2015, 15:59

Having been involved from the flight ops side, we argued endlessly with the bean counters to quip with dual FMS. Our argument is that the landscape in technology terms has about a 10-15 yr turnover, so if for nothing else for the future issues that may not be aware of, we need to spend the extra cash.

Turns out we were both right. We made it a a couple of decades on a single FMS but now are paying the price with diminished capability with NAVAID outages and pending removal. Nothing like having to cancel because the VOR at a small field is down and there's an overcast layer a couple thousand ft high that otherwise wouldn't slow you down.

23rd Jul 2015, 00:09
vapilot2004, certainly we have a language problem here... I talk about coding of navigation databases and you talk about - well ... not about databases ;).

My reference to the Bluecoat mailinglist ( RIP ) was very intentional but thanks for trying :)

23rd Jul 2015, 00:42
Actually the terms I shared regarding NDB approach types are NAV database terminology per ARINC. The part I was a bit unsure of was whether we are talking approach types or arrivals. Both terms were used - perhaps you are divining the mystery of both procedures. So my question, if you have a moment, was just that. Also is any of your quest coming together?

If it is related to approach data, please see my earlier comment regarding one of our members here being a wizard and best of luck solving your puzzle.

Nothing like having to cancel because the VOR at a small field is down and there's an overcast layer a couple thousand ft high that otherwise wouldn't slow you down.

Well that doesn't work very well for scheduled operations, does it?

I am fortunate where I am now to have folks in charge that aren't averse to investing in the company - both people and equipment. Good on you for fighting the good fight!

23rd Jul 2015, 18:48
vapilot2004, yes - it turns out that our problem was the non-standard / unique way the Italians wants to code their STARs and the ensuing confusion created by ATC when not stating "XXXXX STAR via XXXXX transition".

As for "‘Q’ Type approaches"... well - meanwhile I lost interest ;)


24th Jul 2015, 11:10
Thanks for the reply Dusk.

You know, our native language affects how we think and is part of our cultural differences. I have found reading technical material is surely one way to suss out those differences. Some languages are inexact and kind, while others are precise and often accusatory/blame focused - Germanic languages (English) are certainly a member of the latter, yes? In bocca al lupo! (regarding your Italian friends).

As for "‘Q’ Type approaches"... well - meanwhile I lost interest

Ah, well then! :ok:


To you as well!