Copper.

Innsbruck - LOC DME EAST approach procedure

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I’ve spent the day reviewing how the LOC DME approach to runway 26 might be flown with circling for runway 08. In concern is Jeppesen chart 11-1 (or 11-2) for LOWI.

Since it is a LOC DME approach, we can capture and track OEV localiser. We can also expect the glide slope indicator for reference past 19 OEV DME but the descent is to be managed in either VNAV or V/S mode (FCTM - Non-ILS Instrument Approaches). It’s here where things get confusing.

A lot of videos show the use of LNAV/VNAV down to MDA. I see two issues. The lateral path (OEV localiser) is not being tracked by using the OEV localiser (which the procedure is predicated on) as prescribed by chart 11-1 (or 11-2 for that matter), and two, VNAV is understandably used in preference of V/S, however no cold temperature altitude corrections are made when temperatures are at or below 0 degrees C.

What is done in real world? What would you do? Do you fly this LOWI approach in LNAV/VNAV?

I have read the PMDG authored NGX tutorial, however I think it doesn’t go so far as to prescribe how to use automation to complete the procedure into LOWIs runway 08 via LOC DME EAST. I have checked the internet and most use LNAV/VNAV including the real world Transavia 737-800 video.

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Posted (edited)

Hi Brian,

Unfortunately I'm not familiar enough with the B737 to offer a definitive answer beyond the fact that it will probably be operator specific in terms of which modes are approved for use.

However, in the Airbus for a large UK airline it is approved to couple the glideslope (i.e. APP mode) provided the check heights are confirmed.

Remember it is a steep (3.8 degree) glideslope and you will want to be configured nice and early; in the A320 gear down/flap 3/160 kt on the glide to be fully configured at Vapp with landing checks complete by 4000 ft QNH latest.

For landing 08 the normal process is to level off initially at 5000 ft on the glideslope, then at OEV D6 track visually initially toward Axams before intercepting the OEJ backcourse on 066.

You can then descend to 3700 ft (which you can delay until OEJ D9 -- i.e. after the Brenner Pass -- if the Foehn wind is blowing and it is bumpy), and configure for landing. At 3700 ft it's then AP/FDs off, start the right turn at Axams (OEJ D13.8) at 25 degrees angle of bank and start a shallow descent until you are over the ridge (there are some power lines running over the top so not below 3500 ft until you are clear). Once you are beyond the ridge you will then need to increase the RoD to pick up the PAPIs (and remember they are set at 3.5 degrees in the first place), line up with the centreline and land it.

Easy.....!

Edited by skelsey
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Posted (edited)

Thanks. That’s an interesting procedure and I’m left wondering where the MDA/MAPt sits in it, since it seems that that procedure (different to those available in Navigraph charting) keeps the aircraft higher until late in the visual manoeuvre than Jeppesen 19-10 ie. visual manoeuvre accomplished at 3700’ QNH throughout.

As previously said, one of the issues I’m having is regarding altimeters and cold temperatures - both are considerations in LOWI operations during winter. Assuming 0 deg C OAT, the true altitude would be lower than indicated altitude, this should show early in the approach as a discrepancy between onboard altimetery and charted heights when completing required height checks along OEV, if coupled to a serviceable OEV glideslope. If not, and the airplane is following VNAV Path, with OEV tuned, the aircraft would show below the OEV glideslope.

One possibility to mitigate could be that operators use tailored charts which compensate for temperatures in the same way RNP AR procedures do. The charts in the Navigraph solution are designed to PANSOPS which I believe are designed around ISA and would need the cold temperature altitude correction.

As far as the 737 is concerned, it would need autopilot to be cycled to be able to level off if coupled to glideslope, else it will fly through the MCP set altitude, hence VNAV or V/S for vertical control.

Interesting.

Edited by Copper.

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Posted (edited)
43 minutes ago, Copper. said:

As previously said, one of the issues I’m having is regarding altimeters and cold temperatures - both are considerations in LOWI operations during winter. Assuming 0 deg C OAT, the true altitude would be lower than indicated altitude, this should show early in the approach as a discrepancy between onboard altimetery and charted heights when completing required height checks along OEV, if coupled to a serviceable OEV glideslope.

As I understand it:

There is no minimum temperature specified on the RNAV(GNSS) plates for either runway, so if the temperature is below 0C you must correct the crossing altitudes and fly it in LNAV/VS to LNAV minima (because you cannot change the procedure in the box).

The RNAV(RNP) plates specify a minimum temperature of -7C at the airfield, so you are fine to fly these (if you are RNP approved etc) down to this temperature with no corrections. Below -7 you cannot fly the RNAV(RNP) in LNAV/VNAV and must revert to LNAV minima.

The Special LOC/DME East is not an RNAV procedure (though may be coded in the box). The easiest way to fly this I would suggest in temperatures below 0C would be to apply the temperature correction to the MDA (which you would do anyway) and fly it in either LOC/GS (checking the check heights against the corrected heights) or LOC/VS ensuring you meet the corrected check heights. Again, at these temps you couldn't fly it in LNAV/VNAV.

As you say, it is possible that operator-specific procedures exist enabling LNAV/VNAV operations in low temperatures.

43 minutes ago, Copper. said:

Thanks. That’s an interesting procedure and I’m left wondering where the MDA/MAPt sits in it, since it seems that that procedure (different to those available in Navigraph charting) keeps the aircraft higher until late in the visual manoeuvre than Jeppesen 19-10 ie. visual manoeuvre accomplished at 3700’ QNH throughout.

It is the "Special Visual Approach" and it's particularly useful if the Foehn wind is blowing up the Brenner Pass with associated turbulence and windshear as it keeps you slightly higher. The OEJ backcourse essentially takes you directly to Axams without flying a conventional break-off to a downwind so a bit neater in many ways, and the extra height gives you a bit more breathing space!

The MDA remains 3700 ft QNH, but remember it is a minimum -- if you're visual earlier there's no need to rush to descend lower than you need to and indeed it is often advisable to level off a little higher rather than drag it round the circuit right at the MDA (which could in theory be as low as 600 ft aal for a Cat C aircraft). If the cloudbase is really low (and this is unlikely at INN with an easterly wind) then rather than briefing the Special Visual I would plan to continue on the LOC/DME down to MDA/MAPt and then fly a conventional circling procedure as charted in Navigraph assuming visual at that point.

The most interesting thing about INN, of course, comes if you have to go around below MDA (even more so if you are OEI!) as the published instrument missed approach will not protect you at this point!

Edited by skelsey
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On 6/28/2018 at 1:09 AM, skelsey said:

There is no minimum temperature specified on the RNAV(GNSS) plates for either runway, so if the temperature is below 0C you must correct the crossing altitudes and fly it in LNAV/VS to LNAV minima (because you cannot change the procedure in the box).

Ok that makes sense. I know you cannot modify RNP AR procedures, I don't know about others including this PANSOPS LOC DME procedure.

On 6/28/2018 at 1:09 AM, skelsey said:

The RNAV(RNP) plates specify a minimum temperature of -7C at the airfield, so you are fine to fly these (if you are RNP approved etc) down to this temperature with no corrections. Below -7 you cannot fly the RNAV(RNP) in LNAV/VNAV and must revert to LNAV minima.

You can understand why we have moved to RNAV (RNP) as it is more comfortable and safer, but RNP AR is not what is being considered in this thread. The LOC DME EAST procedure is.

On 6/28/2018 at 1:09 AM, skelsey said:

It is the "Special Visual Approach"

Is it charted and available to the general public?

On 6/28/2018 at 1:09 AM, skelsey said:

if you have to go around below MDA (even more so if you are OEI!) as the published instrument missed approach will not protect you at this point!

I'll have to give it a try some time. Engine failure on level out from base turn to RWY08 centerline.

This is an approach I did following 11-1/19-10 Jeppesen charts. VOR/LOC then HDG SEL for lateral tracking and VNAV then ALT HOLD for vertical. I don't know if FSX's OEV loc is accurately placed, if anyone has tips here to make it as accurate as can be thank you. LNAV seems to draw a path offset from OEV which I think would put the airplane overhead Kellerjoch (will try/fly the LNAV one day for comparison). I add 50ft to MDA (3700' + 50') and set 3800' in the MCP so my decision is made above MDA, usually 3800'. Kellerjoch is the main problem. Gotznerberg is another hotspot to monitor carefully even though visual.

r.jpg

 

Is there any laws that allow an overlay of raw data for tracks? I.e. follow/create an LNAV path, but have the raw data tuned and monitoring it

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That approach looks exactly like the one used in the NGX Tutorial #2.

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6 hours ago, downscc said:

That approach looks exactly like the one used in the NGX Tutorial #2.

It is. I’m using Kyle’s tutorial as principal guidance. I particularly liked his decision to use F15/GearDown from before FAF to the downwind segment instead of landing configuration.

It seems more practical to me for a few reasons but mostly because the Missed Approach for LOC DME EAST 11-1 needs a turn to backtrack 075crs OEV at approx 155knots, 25deg left bank from 1.0nm OEV. Guess what flap setting gives approx 155knots? You guessed it, F15 - incidentally, F15 happens to be the Go-Around flap setting. Thus, if going missed there is less to think about (speed/flap setting). The pilot can concentrate on max gradient climb (thrust/pitch settings) and the turn to backtrack.

It is an excellent tutorial. I did note one insignificant omission - the glide path (-3.77) not set for HGS. Also an error earlier on regarding hydraulic quantity check during preliminary preflight. The arrows point to pressure instead of quantity. 

One thing I question (not criticize) - the use of LOC DME WEST Missed Approach. Was that used because the charts used didn’t have a missed approach published at the time of writing?

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Posted (edited)

Hello Guys,

These kind of posts make 's one forget it is a desktop simulator, it is more like an airline's training.

B.t.w, is it true that, in order to fly this approach, pilot's need an extra training/certification?

 

 

 

Edited by wijnand

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10 hours ago, wijnand said:

is it true that, in order to fly this approach, pilot's need an extra training/certification?

I believe it would be. Isn't it amazing what PMDG has enabled us to do! 737, 777, 747.

On 6/28/2018 at 1:09 AM, skelsey said:

because you cannot change the procedure in the box

Simon - I did a little research out of interest. It looks like this varies. Some states permit alteration of coded speed and altitude restrictions. Some permit alteration between Initial Fix, Intermediate Fix and the Final Approach Fix but not after the FAF. Some don't permit alteration at all. So, with respect to my Cold Temperature Altitude Corrections to FMS VNAV Path - yes, I would need to alter (add) altitudes. That would mean if I intended to use VNAV for the LOC DME EAST 11-1, and temperatures were at or below 0 degrees C, I would have to make changes or use Vertical Speed or use another procedure.

20 hours ago, Copper. said:

Is there any laws that allow an overlay of raw data for tracks? I.e. follow/create an LNAV path, but have the raw data tuned and monitoring it

I didn't find any specific regulation yet, but - I did find in ICAO PANSOPS 8168 that FMS/RNAV equipment can be used to fly conventional procedures provided the same displays are monitored as if you wern't using FMS/RNAV equipment. the manual lists certain Precision Approaches and Non Precision Approaches as conventional procedures. I think LOWI LOC DME EAST 11-1 would fit in the conventional procedures category. It is probably best to note that the operator would obviously need to get approvals to do this.

In FSX - I updated NavAids and ILS/Rwy data via this http://www.aero.sors.fr/navaids3.html 

I then flew the 11-1 procedure at the ORBX LOWI scenery firstly in LNAV, then in VOR/LOC coupled to OEV localizer. I used VNAV for both tests. There is an obvious difference between the respective lateral paths. Why?

s.jpg

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The navigation performance looks different, is this because the LNAV track was based on 0.30 being in the terminal area where as the VOR/LOC tracking was not in approach mode?

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On 6/30/2018 at 10:57 PM, Copper. said:

Is it charted and available to the general public?

I've had a look and I can't find it anywhere but it is in the RW (textual) notes issued to that particular large airline's pilots.

15 hours ago, wijnand said:

is it true that, in order to fly this approach, pilot's need an extra training/certification?

Yes, as a Category C aerodrome the Austrian CAA require the handling pilot (and in most airlines Innsbruck will be a Captains Only landing) to have competed some training which is actually outlined in the chart notes - essentially either a visit in VMC (normally with an INN-qualified Training Captain) or training in a simulator before operating in to INN under IMC or at night.

On 6/30/2018 at 10:57 PM, Copper. said:

Is there any laws that allow an overlay of raw data for tracks? I.e. follow/create an LNAV path, but have the raw data tuned and monitoring it

As you mentioned above - the general view with regard to NPAs is that it doesn't particularly matter which modes you use to track provided that you monitor the raw data and ensure you remain within normal tracking tolerances. So yes, absolutely you can fly a LOC (or VOR, or NDB etc) procedure in LNAV provided you have tuned, identified and are monitoring the raw data to verify tracking accuracy. What you cannot do is use the RNAV procedure to replace the raw data if e.g. the LOC is out of service (nb: I believe some carriers have approval to use RNAV overlays for NDB and VOR approaches even if the primary navaid is unavailable).

4 hours ago, Copper. said:

There is an obvious difference between the respective lateral paths. Why?

Good question! Sure you were tracking OEV using the localiser and not OEJ? The LNAV track looks correct at a glance.

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6 hours ago, downscc said:

The navigation performance looks different, is this because the LNAV track was based on 0.30 being in the terminal area where as the VOR/LOC tracking was not in approach mode?

Like Simon, I think the LNAV path is actually correct and the OEV localizer beam is in error. For some reason the OEV course is 253deg mag in my machine. LNAV path gives correct/expected course of 255deg mag. For the record, RNP/ANP 0.30/0.07 lateral, and I manually changed vertical RNP to 125'. There was little to no cross-track error. I have the Navigation Performance Scales enabled and they did not alert me to an exceedance.

4 hours ago, skelsey said:

Sure you were tracking OEV using the localiser and not OEJ?

Certain. I agree, LNAV looks correct and the localizer looks wrong.

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