LNAV NDB approach

[AFlora]

Hello everybody

My question is: Is it legal to fly NDB or NDB/DME approach in LNAV FD/AP mode while non-flying pilot is monitoring raw NDB data ?

Thank you.

[Wizofoz]

Yes,

Though why not fly in LNAV with the raw data an the PFs ND? Is it not possible to have the ADF needle displayed along with the LNAV track on your aircraft?

[AFlora]

Sure, I can see the NDB needles on my aircraft, that's not a problem.
But some my colleagues state that it's not legal to fly in LNAV mode, so I should use HDG/TRK mode.

[Mikehotel152]

Wouldn't you always back up LNAV with raw data when flying a STAR, Approach or SID?

[Wizofoz]

Aflora,

Ask them to back that up by reference to the Regulations!

There is no regulation about HOW you fly the approach, only that you fly it with reference to the appropriate aid.

Mike hotel, htese days most SIDS and Stars are RNAV and do not reference am aid.

[AFlora]

Thank you, but I still have some doubts

As they said, one of the main causes of Tu-134 crash in Petrozavodsk, Russia, is using of GPS on NDB approach, while some waypoints coordinates on final approach mismatch the actual WGS-84 coordinates. It's typical for Russia region where the SK-42 were used instead WGS-84 for long time.

AC120-29A states: 4.4.2. FMS Use for Procedures Other Than xLS or RNAV. FMS may be used to conduct VOR, VOR/DME, NDB, NDB/DME, LOC, and LOC Back Course approaches when suitable navigation position updating which
provides required accuracy and integrity is used by the FMS (e.g., DME-DME-IRS, or scanning DME, or VOR/DME, or GNSS position updating, or Localizer (LOC) updating, etc.).

So, I can use LNAV on any NDB approach while FMS in GNSS or D/D or V/D position updating? Or only charts with "NDB (GNSS)" statement?

Thank you

[Wizofoz]

Two different things. That's what you need to conduct an NDB( or other NPA) WITHOUT the raw data.

If you are using the aid to navigate, you can fly in any mode you like.

[binzer]

we fly Lnav /vs with adf needle overlay. also vor can be lnav with other guy on green needles. can also stick pre view under FD

[AFlora]

Ok.
Let's see into two LSZH (Zurich) VOR approach charts with two different headers:
- VOR Rwy 28
- (GPS) VOR Rwy 34
As I understand, I can fly in LNAV mode both approaches, but on VOR Rwy 34 it's allowed to use FMS (and LNAV mode) ONLY if FMS is in GPS updating mode.
Is that right?

[Broomstick Flier]

The way I see it the approach to rwy 34 can either be done with GPS or VOR reference.

On my current job we fly NDBs with the PF displaying FMS data with both needles overlaying ADF data and the PM displaying green needles and the RMI needles selected to ADF and FMS (that one for cross checking the FMS data).

Approach can be flown either using NAV or HDG.

[Mikehotel152]

these days most SIDS and Stars are RNAV and do not reference am aid.

I wouldn't say 'most'. In fact, in western Europe I would say 'a minority' do not reference a nav aid. The majority of RNAV approaches around here are overlay approaches and while strictly speaking unnecessary, raw data backup is worth doing. That's just my opinion (and company SOP).

As for an approach based on an NDB, I imagine tuning the beacon is standard practice for most people, no?

[ersh2k4]

in the company i fly for, the SOP standart for an NDB app is actually LNAV with the PM side in raw data for monitoring.

so yes, its legal, and in some cases like mine its what the company wants.

[777boeings]

I'm with Mikehotel152. When flying an NDB approach there is absolutely no excuse not to tune the relevant beacon. Likewise, when cleared direct to an NDB, we all know that we can select direct to that beacon in the FMC and engage LNAV, but good airmanship dictates that the beacon is also tuned and that basic tracking is monitored. Same goes for NDB holding patterns.

[PT6A]

We fly it managed / managed... Infact not allowed to fly it selected by our own company rules.

Flying in none WGS84 airspace is another issue however... As I dont currently do it... I would need to look it up... But from what I remember our ops manual does not let us fly the approach in managed unless it is in a list of procedures in our ops manual that have been "verified"

But in short for us we are not allowed to fly an NDB in heading select... It has to be done via the FM.

[Capt Claret]

The Douglas/Boeing FCOM required raw data to be set on at leastone of the ND for a VOR/NDB approach. Said approach can only be flown in NAV if it is loaded into the FMS from the FMS data base. In other words, one can't build the approach with PBD and then fly it in NAV and/or PROF.

[john_tullamarine]

one can't build the approach

Very naughty to do that. The box accuracies are different as I understand between what the pilot and the database OEM can do. More than a few mishaps have had pilot built approaches implicated in the swiss cheese sequencing of events.

Hopefully one of our procedures experts will jump in to comment.

[Denti]

Raw data monitoring is recommended but not required anymore. All non precision approaches are flown as IAN which means the same presentation and basic procedure as an ILS, however the final approach course and glide path are FMC generated. That means of course that the approach has to be in the database, self generated procedures are not available and not allowed. During winter one has to be careful about temperature correction and in case of FMC procedures about the temperature limit for that particular procedure.

Generally we have tuned the NDB and have the needle on our ND, same for VOR approaches. LOC approaches have to be flown with reference to the localizer anyway which is then shown on the PFD. That is for the 737 fleet, dunno how they do it on our busses (A320/A330).

[Capt Claret]

one can't build the approach

Interestingly, for reasons unknown, several NDB approaches are not in the database. Eg, YAYE NDB only has the final section of the approach coded, not the reversal turn.

[AFlora]

For now I'm convinced in the next statements:
- I can fly any NPA in LNAV mode if procedure has generated by FMS from database;
- It's strongly recomended to monitor the raw data from relevant beacon for cross-check, because of probable mistakes in the database, FMS faults or manual entries;
- It's restricted to use FMS in non-GPS (DME/DME etc. ) updating mode if NPA requires GPS (DME/DME etc)

[rudderrudderrat]

Hi John,
Very naughty to do that.I agree.
Some crews seem to believe that the published Jeppesen / Aerad Non Precision Approach, (based on radio aids) can be replaced by the RNAV display for the overlay.

Building one's own approach in the FMC / FMGC with an undetected error will only mislead the crew. The overlay method was supposed to enhance situational awareness but some to seem to believe it can now be used in stead of the published approach.

If the Jep plate says RNAV GNSS / DME/DME then "fill your boots" - else you must display and monitor the published aids.

[john_tullamarine]

And the saddest thing I see is that all the wisdom we (of decrepit age) had beaten into our stupid skulls by not so PC training captains using all manner of rolled up newspapers across the back of the head, etc., to get the message across ... appears to have gone out the window in the current Industry marketplace.

For instance I recall, as a VERY new airline F/O (with not much prior background) having a training captain thrust into my hand his copy of Fate is the Hunter with the admonition that I was to read it prior to the next flight the following day. After reading the book (and, in particular, the match in the face anecdote) I still can recall quite clearly thinking to myself .. no-one had previously told me that THIS is what flying and command is about.

Spoon feeding is for high school kids. Pilots need to be a bit independent and exhibit a bit of initiative.

[Capn Bloggs]

Interestingly, for reasons unknown, several NDB approaches are not in the database. Eg, YAYE NDB only has the final section of the approach coded, not the reversal turn.
I believe, Bloggs, it is/was because there was no VOR/DME to provide updating (despite the presence of vastly superior GPS positioning). That is changing, from what I can see.

[halas]

The mob l work for has announced all new delivered airframes (and there are a lot of them!) will not have an ADF installed.

Hence forth you may fly a line selectable NDB approach using RNAV.

halas

[FlightPathOBN]

It is fraught with disaster to try to input your own waypint data and/or procedures. Within the navdatabase, you could override the existing data, or worse over-ride an existing waypoint with your custom data.
There is significant coding that goes into a waypoint, and this all predicts the performance..The user has no way to input flyover or flyby, speed restrictions, at or above, or other data that significantly affects how the aircraft will perform.
I know of at least one incident, where as soon as the ac crossed the waypoint, the ac porpoised down the the MDA before the operator could react.

Dont get caught with anything in the box that was generated by your navdatabase provider.

Ask them to back that up by reference to the Regulations!

Here are the regulations that specifically and otherwise prohibit an operator from entering their own IFR waypoints.

ICAO Annex 15, Doc 8126
RTCA ED-76, ED77, DO-200A, DO-201A
ARINC 424
FAA AC20-DB

[Capn Bloggs]

OBN, you are getting carried away a bit. We cannot overwrite database waypoints or their stored characteristics. It is possible to create a duplicate but one cannot change a DB waypoint (apart from editing the altitudes and speed once it is in the active flight plan).

Yes, we cannot create a user flyover waypoint (which is a nuisance as it would be handy; have a look at the YPAD RIKAB 6V (http://www.airservicesaustralia.com/aip/current/dap/PADSR12-129.pdf) visual STAR, which is not in the DB, specifically GLOBE.

It is a simple matter to constrain the aircraft at any waypoint to ALT AT, ALT AT or BELOW or ALT AT or ABOVE. Same with speed restrictions (although I am annoyed you can only nominate a speed AT or BELOW; I would like AT or ABOVE as well! :}).

The mob l work for has announced all new delivered airframes (and there are a lot of them!) will not have an ADF installed.

Hence forth you may fly a line selectable NDB approach using RNAV.
Just because an airframe isn't fitted with a navaid doesn't necessarily mean that you are automatically authorised to conduct terrestrial approaches with sole reference to LNAV.

[halas]

You tell this mob that, Capn Bloggs.

I agree. Although having only done one NDB with this outfit, it was done in LNAV and VNAV. Bottom line is, with autopilot on, the ADF's were superfluous except to "pretty-up" the ND with some blue arrows that funnily enough, lined up with the pink line on the outbound and inbound tracks!

halas

[rudderrudderrat]

Hi Halas,
the ADF's were superfluous except to "pretty-up" the ND with some blue arrows that funnily enough, lined up with the pink line on the outbound and inbound tracks!
The ADFs were certainly not superfluous if you were conducting the NDB Approach.
However, if you were conducting the RNAV approach - then they were superfluous.
Which one were you doing?

It's explained here:
http://ww1.jeppesen.com/download/aopa/apr00aopa.pdf
e.g. Manchester RW23L has an RNAV Approach, and a VOR Approach. Both have exactly the same track.

[Capt Claret]

An NDB approach in the 71 is typically flown after loading the database approach into the FMS, in NAV & PROF to the minima, with ADF pointers selected on both sides, and usually the PM/PNF/Support Pilot's ND set to APPR, with a pseudo ILS course bar (to aid track keeping).

[Centaurus]

Part of the command instrument rating test includes demonstrated competency at flying an NDB approach. Flying it in LNAV is not proof that the candidate is competent at that task. For the same reason an autoland is not proof that the candidate can manually land an aeroplane. The autopilot does a sterling job of most LNAV features but the skills test is not of the autopilot but of the person. Therefore the candidate is required to prove he can hand fly using normal tracking skills on an NDB and not the artificial "crutch" of LNAV.

[BOAC]

Yes, JT, bring back the rolled up newspaper. I cannot believe we are still going round in circles here - flying an NDB approach without an ADF fitted? A bit like watching TV on your radio. It has been said many times before - if the approach is an NDB that is how you fly it. If it has 'RNAV' or 'GPS' or whatever, that is how you fly it, but if the 'old' nav beacon info is there on the chart I suggest it is damn fine idea to back it up if you can.

[halas]

RRR
Thanks for the article. No mention of NDB approaches in my quick glance.
If an NDB approach is line selectable from the FMC then RNAV is to be used with full automatics to be used, as Capt. Claret has mentioned.
This goes for any VOR approach as well.

Centaurus
(Great sounding motor by the way) We are not talking about initial IR ratings. This is in the field regulated and company requirements being met.

BOAC
More like watching TV on your iPhone. Tolerance monitoring is ideal, l agree.

But if there are no ADF's installed, how are you to do that?
The best offer is RNP, which is a minimum requirement on an RNP RNAV approach anyway.
As long as the approach is validated for dist/TRK/GPA and minimum crossing altitudes (plus temp if required) and the minimum RNP is available, then why not?

halas

[BOAC]

More like watching TV on your iPhone- not really - you CAN get TV on the Iphone.:rolleyes:But if there are no ADF's installed, how are you to do that? - what is 'that'?

[PPRuNeUser0190]

As always Doc8168 to the rescue :)

1) naming convention: if the navaid is in the approach chart title, then you need that navaid and a suitable receiver... an NDB approach can not be flown without an ADF.

2) Doc 8168 section General principles, general information:

USE OF FLIGHT MANAGEMENT SYSTEM (FMS)/
AREA NAVIGATION (RNAV) EQUIPMENT
1.4.1 Where FMS/RNAV equipment is available, it may be used to fly conventional procedures provided:
a) the procedure is monitored using the basic display normally associated with that procedure; and
b) the tolerances for flight using raw data on the basic display are complied with.

[swh]

Part of the command instrument rating test includes demonstrated competency at flying an NDB approach. Flying it in LNAV is not proof that the candidate is competent at that task. For the same reason an autoland is not proof that the candidate can manually land an aeroplane. The autopilot does a sterling job of most LNAV features but the skills test is not of the autopilot but of the person. Therefore the candidate is required to prove he can hand fly using normal tracking skills on an NDB and not the artificial "crutch" of LNAV.

That is not right, I would like to see you do a 3b into YMML without an autopilot.

From CAO 40.2.1

"An autopilot or a coupled approach may be used in the demonstration of proficiency in instrument approach procedures."

"coupled approach means an ILS approach whereby the aircraft is manoeuvred by the autopilot in response to signals received from the ILS ground installation."

[AFlora]

halas

- But if there are no ADF's installed, how are you to do that?
It seems to me you can't do it without ADF installed or RNAV APCH statement. I mean - to conduct NDB appoach without ADF needles in the minimum at all. It's your own risk.

[rudderrudderrat]

Hi halas,
No mention of NDB approaches in my quick glance.
Correct! That's because it's all about RNAV approaches. Clue - it's written in the top right hand corner of the Jep plate.

Using your logic - you could do an ILS without displaying the LOC & GS by flying the RNAV approach.

What limits do you bug when doing the NDB without an ADF?

[halas]

NDB minima.

And you are correct, you could follow the ILS completely on RNAV. Having both displayed on the PD, the only time they really deviate is at the bottom as the VNAV is using the piano keys as a reference.

With RNP at less than 0.3 or better in approach phase conducting a LOC/VOR/RNAV/GNSS is fine. The last two have no reference aid at all. And the last one is for the Seychelles (CAT C) sliding along the mountain range in a turn on to short finals, or for JFK for 13L/13R to near CAT I minima.

However performing a line-selectable NDB approach without an ADF, but with RNP usually around 0.1 or better seems daunting.

NDB approaches have huge tolerances built in. If there was little room for error then another aid/approach would be there instead.

And it's not my logic. It's the way things are changing toward.

Believe me, if the NAV SYS fell over and the only approach available was an NDB, l would be wanting ADF's there in front of me. But l guess that is a calculated risk by the manufacturer, the company and regulator.

halas

ps: For those not familiar... Line-selectable means the approach that is desired is available in the aircraft nav data base which is updated every 28 days.
This is validated against the chart for the same approach for distances, bearings, speed limits, timing, altitude constraints and temperature.
RNP 0.3 equals 0.3 of one nautical mile before an alert for UNABLE RNP is sounded.

[rudderrudderrat]

Hi halas,

Your example of JFK 13L/R VOR or RNAV does include "RNAV" in the top right hand corner and may be flown using RNAV only presentation.

Where is the NDB approach which you claim can be flown without an ADF?

[swh]

Where is the NDB approach which you claim can be flown without an ADF?

Those that I am familiar with are the NDB/VOR overlay approaches in North America. No requirement to have the equipment fitted to the aircraft if the GPS/operator etc is approved.

[halas]

RRR

I have never stated that l have flown an NDB arrival without an ADF.

The NDB approach l did do was line selected, verified and flown with LNAV and VNAV with the autopilot on with an ANP of around 0.05 with no intervention on the MCP except to slow down as appropriate, down to the NDB minima.
At which point the autopilot was disconnected and a safe landing was conducted. There was no RNAV on the plate however as l mentioned before the ADF needles were present with a continuos monitoring of the beacon and everything worked out well.

Is there a safety issue?

halas

[rudderrudderrat]

Hi halas,

Sorry - I confused The mob l work for has announced all new delivered airframes (and there are a lot of them!) will not have an ADF installed.
Hence forth you may fly a line selectable NDB approach using RNAV.
as meaning you will be able to fly an NDB approach without any ADF.