Confusing chart at LOWI

[Nevian 0]

I'm attempting the RNAV approach to 08 at LOWI, Innsbruck beginning at ELMEM as the IAF.

When looking at the chart I'm confused about a few things. First of all, the missed approach point is 12,7 nm from the runway. Also, after this point the route is dashed without any clear indication on why, except that the slope changes slightly. When feeding this into the FMC it also presents descent issues.

Can someone explain? Thx  :smile:

[brucek 38]

I don't have the IAP, but usually a MAP displaced this far from the runway indicates that the climb to altitude is challenging, so the MAP displacement allows some of the finall approach real estate to be a part of the path.

 

A dotted line sounds like a visual segment, is there a VDP on the chart?

 

Bruce.

[icemarkom 59]

Granted I look only at the FAA charts, but dotted line after the runway usually simply means the path to take for the missed approach. No other special meaning.

[Nevian 0]

The dashed segment has a couple of waypoints on it with the prefix MATF - which I have now found to mean Missed Approach Turning Fix, proving that it actually is a missed approach segment. I suppose that means that the remaining part is to be flown visually. Still I don't get why the missed approach point is so far away...

[brucek 38]

Approaches are built on altitude changes expressed as feet / nautical miles, since this is independent of speed. (Pilots then convert this to feet/minute by multiplying the above number by knots/60). So, assume that the required climb gradient to clear an obstacle on missed approach is 4,000 feet/nm (an over-exaggerated figure of mine that means nothing other than to demonstrate this issue)..

 

But assume that the approach designers want to keep the climb gradient down to 1,000 feet/nm, to accommodate all sorts of airliners (again, another fictional figure just to demonstrate this). One solution would be to lower the obstacle, but if that is a mountain, this might be a little hard to do...... So another solution is to increase the distance so that the required altitude climb is amortized over a longer distance. To do this, they could move the obstacle further away from the runway (again, not practical if it's a mountain). Or, they could (either or both) raise the missed approach height (DH or MDA), and/or move the MAP away from the runway in the opposite direction of the obstacle.

 

There are some things that are "red flags" to instrument fliers- and either an unusually high DH/MDA and/or an unusually large MAP displacement from the runway threshold is a sure sign that the missed approach has an aggressive climb involved- so be aware.....

 

I don;t know this approach and don;t have it, so there could be other issues that might cause the MAP to be located to this position- I'm just giving you my first gut reaction to your question...

 

Thanks, Bruce.

[gandy 18]

after this point the route is dashed without any clear indication on why,

 

 

Thats the part where visual rules apply, 5nm for that airport.

[MrPlaneDriver 41]

Still I don't get why the missed approach point is so far away...

 

That could be because of the high terrain around. The MAP is 12,7NM away from the runway, which you should cross at the MDA (6000ft). At that point, both to your left and to your right, there is already terrain rising up to 4000ft above you. The airport itself is at 1907ft MSA, so it's a long climb through a tight valley to get out of there safely.

 

Another possibility is that the RNAV approach is for "cloudbreaking only", as a remark in the approach plate says. I assume that means that, by the MDA, you should be completely clear of clouds, otherwise the approach must be discontinued. Also, the minimum ceiling for this procedure is 4100ft AGL. Since the airport is at 1907ft MSA, it means that the lowest cloulds should be above 6007ft for the approach to be attempted.

[rcpistonhead 47]

Here is a great video going in depth on the 08 approach...

 

[fschrewe 0]

 

 

I'm attempting the RNAV approach to 08 at LOWI, Innsbruck beginning at ELMEM as the IAF.

When looking at the chart I'm confused about a few things. First of all, the missed approach point is 12,7 nm from the runway. Also, after this point the route is dashed without any clear indication on why, except that the slope changes slightly. When feeding this into the FMC it also presents descent issues.

Can someone explain?

 

Hello Thomas,

The explanation is quite simple. Innsbruck is located in the valley of the "Inn" river and is surrounded by high mountains.

If you are arriving from the east with RWY 26 active you can use a LLZ approach with a 5° offset to the runway.

For arrival from the west the mountains are so close to the runway that you have to fly over the runway at 500ft MSL and make a turn for a visual approach. For the same reason approaches for RWY 08 are also flown visual as you have to stick very close to the mountains south and west of the airfield.

As these procedures are supposed to be flown by hand, they are actually not even part of up-to-date Navdata to prevent pilots from trying to fly them by autopilot...

 

For your RNAV approach: Although the MAP is 12.7 miles away from the airfield, you are already down to 5000 ft MSL at that point, while the mountains around have more than 9000 ft, possibly blocking some GPS signals. From this point you have to follow the valley visually.

 

In real life many airlines have company procedures allowing their pilots only to use the LOC DME east approach for RWY26 - or reroute to an alternate airport for safety reasons.

 

A complete Chart package for LOWI (including the visual approach chart) can be found here: http://www.vacc-austria.org/?page=content/chartlist&icao=LOWI

 

 

Frank

 

P.S.: sorry for my english, it's not my first language...

[mosteen 111]

Great English Frank, no worries Thanks to all of you for an interesting thread, I just installed Approaching Innsbruck and will start to practice for the different scenarios offline in my 737.

 

I see that LOWI is often manned on Vatsim so online would be my next step. My VA have EGKK-LOWI on the 737 winter schedule so at least I'll be ready for that.

 

Cheers,

[Chrjs 61]

Great English Frank, no worries Thanks to all of you for an interesting thread, I just installed Approaching Innsbruck and will start to practice for the different scenarios offline in my 737.

 

I see that LOWI is often manned on Vatsim so online would be my next step. My VA have EGKK-LOWI on the 737 winter schedule so at least I'll be ready for that.

 

Cheers,

 

Theres is even gonna be a HIgh-Traffic Flyinn Event for LOWI on August 11th (LOWI-EDDN) - be sure to bring enough fuel for holding (last time i was circling around 60min), or even a diversion due to traffic to LOWS.

EIther way, i guess on VATSIM LOWI has more traffic on VATSIM even without the events compared to the real world counterpart!

[mosteen 111]

Thanks mate, I'll be busy before the 11th of August then

[JetNoise 0]

You might also check on YouTube. Look for skysurfer007,

 

Innsbruck circling 08

Have fun

 

JetNoise, LHA731

 

Gesendet von meinem Nexus 7 mit Tapatalk 2

[mosteen 111]

Thank you sir!