View Full Version : LNAV/VNAV non-precision approach on Boeings???

8th Jun 2008, 21:36
Dear colleagues,

Don’t you know, is it necessary to have some special CAA approval to fly LNAV/VNAV non-precision approaches with B737 in UK or another EU countrie? :confused:

flite idol
8th Jun 2008, 22:05
Not sure about the CAA regs, many Jepp plates have a ball note to the effect that approved operators can use a lower published DH in lieu of the MDA or some such thing. I`m sure someone will clarify that!

Spooky 2
8th Jun 2008, 22:47
In the US the operator would need to have their respective Ops Specs annotated so as to allow these procedures to be used. This would in turn assure compliance with the specific aircraft and equipment being utilized, i.e., Pegasus, PIP, GPS, Non GPS. Also the training program used to qualify the flight crews. I would imagine something simialr exists in GB as well.

8th Jun 2008, 23:34
Yes you do need CAA approval and you also require an appropriate training program for your pilots prior to be up and running.

9th Jun 2008, 00:12
Of course, if we look back in time (say, ten years or so), we find the following...
Lockheed L1011.
Equipped with Honeywell HT9100 dual FMS/GPS units.
Fully certified for, enroute, terminal, approach (...ie; NPA).......and they worked to perfection.
And, still do.

9th Jun 2008, 00:19
LNAV/VNAV approaches fly to a DA (decision altitude) rather than an MDA (Minimum Descent Altitude). I currently fly these approaches under the US FAA part 135 (Gulfstream GIV) and yes the operator has to be approved. Same in other countries too.

9th Jun 2008, 07:29
I guess it depends on the local authority how they handle that stuff. We got minimal training (just flying one LNAV/VNAV or IAN approach during normal SIM checks) and are approved to fly them down to MDA serving as a DA for non precision approaches. Only restriction is that we have to use the autopilot on approaches with an RNP of 0.15 or lower until visual reference is aquired during the approach.

Of course IAN makes it even easier as you fly the NPA absolutely the same way as you do ILSs with the exception that you can only use one autopilot.

9th Jun 2008, 11:12
This unit was not specific to the L1011 though. Fitted to a number of a/c including large and small Boeings, some M-Ds and early Airbus. I can't remember exactly raving about it. I have one mid-atlantic airfield in mind that has a non-precision approach with an offset TACAN and an NDB in the most useless place other than to indicate where a decent steak might be had. The approach lights there always looked pink but the tea and banana cake was worth the trip. Without wishing to provoke an A vs B argument the MMI A330 that used to go there always seemed to have a better approach than many.

9th Jun 2008, 11:35
Just a quick question to the guys approved to fly LNAV/VNAV approaches.

What means do you use to correct for low temperatures during winter operations?

We are not allowed to fly them due to the fact that we are not allowed to do corrections to the vertical profile of the published fms-(fmgc)fixes.

Do you have a specific temp-range you are allowed to fly them, or does the profile change if you put in current temperature of the field in the fms (fmgc)?

10th Jun 2008, 00:32
LNAV/VNAV approaches should have the lowest valid AD temperature annotated on the chart.

10th Jun 2008, 00:46
OUr latest software updates make the height corrections automatically, when we put the aerodrome conditions into the approach section of the FMS....pretty cool. That allows us to use them!

10th Jun 2008, 00:55
Re “…make the height corrections automatically”, but whatever cleverness the software has, it still depends on an accurate input. Similarly, doesn’t the generation of VNAV waypoints also depend on setting the correct QNH.
So VNAV is a more accurate system, but there are just as many if not more opportunities for error; - a need for good crosschecking SOPs and always select EGPWS terrain display on one display.

10th Jun 2008, 10:37
EASA has just published draft material covering approvals for RNP APCH (LNAV/VNAV to RNP 0.3) and for RNP AR APCH (LNAV/VNAV to RNP 0.1 with fixed radius turns in final/missed) See
http://www.easa.eu.int/ws_prod/r/r_npa.php (http://www.easa.eu.int/ws_prod/r/r_npa.php)

26th Jun 2008, 20:17
OUr latest software updates make the height corrections automatically, when we put the aerodrome conditions into the approach section of the FMS....pretty cool. That allows us to use them!

What plane is it? Boeing?