Garmin working on Baro VNAV to missed approach point

[Dick Smith]

There is no doubt that Garmin is one of the leaders in aviation equipment. Disappointingly, they lag far behind when it comes to a Baro VNAV approach. With the Collins Proline 21 equipment, all GPS approaches can be fully coupled right to the missed approach point. This obviously improves safety as the pilot can monitor the approach without having to manually fly a particular rate of descent.

I have personally been mystified why Garmin do not provide this type of coupling with their G1000 system. After all, it has a fully certified altimeter and you would think it would just be a simple change to have the approach coupled to the missed approach point.

Here is a recent answer to a query from Cessna regarding Garmin for the Mustang. It looks as if it is going to happen at some time.

Currently we only provide baro VNAV for enroute and terminal phases of flight and not any part of the approach phase (or missed approach). The Mustang is not capable of having baro VNAV down to the missed approach point with its current software. Garmin engineering have been working on development of baro VNAV for approach phases of flight. However this is still in development in engineering and is most likely a year or more out from Garmin. Also, there is time added in for the Cessna certification and implementation to the field which we at Garmin could not predict since that is up to Cessna. So with that said we really could not give you a time frame.

[27/09]

There is no doubt that Garmin is one of the leaders in aviation equipment. Disappointingly, they lag far behind when it comes to a Baro VNAV approach.

Probably because they have focused on WAAS technology, which in my opinion is vastly superior to VNAV baro by giving localiser precision with vertical guidance allowing coupled approaches to 200 feet DH.

However the authorities in this corner of the world are ignoring WAAS which is a crying shame.

GPS NPA approaches are more dangerous than a VOR/DME or for that matter an NDB/DME approach due to the difficulty to moniotor the profile due to the way the GPS counts down the distance to go. The vertical guidance provided by WAAS greatly reduces the risk.

I wonder how many lives will be lost before they realise the folly of their actions?

[Jenna Talia]

I wonder how many lives will be lost before they realise the folly of their actions?

Totally agree. However, it is more like the folly of their inactions!:ugh:

[blueloo]

Dick just upgrade to a 777 or 787 when they come out. Then you can use VNAV or LNAV.

[ForkTailedDrKiller]

GPS NPA approaches are more dangerous than a VOR/DME or for that matter an NDB/DME approach due to the difficulty to moniotor the profile due to the way the GPS counts down the distance to go

27/09 - With all due respect, that is just NOT so.

How many GPS/RNAV approaches have you flown, and with what equipment?

What you say may be so for the 1st generation of approach approved GPSs but is not true for G430/530/1000 type of units. GPS/RNAV approaches flown with that gear are as easier to fly and therefore safer than VOR/DME and certainly NDB/DME.

With the moving map page selected on the G430/530 there can be no confusion about where you are on the approach.

Dr :8

[27/09]

Dr.

I think you misunderstand what I was getting at.

I have flown plenty of GPS approaches, not quite daily but certainly on a regular basis. Yes, they are mainly on earlier TSO C129 type GPS's with some on new TSO C146 GPS's, however your flash 430/530/1000 with their moving maps do not solve the problem I refer to. That is being able to monitor the approach profile with a quick mental calculation.

Here in NZ most VOR and NDB approaches use a 5% or 300'/nm profile and it is very easy on a VOR/DME or NDB/DME approach to very quickly calculate your profile. If we look at the NZTG NDB/DME RWY 25 approach. http://www.aip.net.nz/pdf/NZTG_44.1_44.2.pdf

The profile at 5 DME is 1300 feet which equates to 300 X 5 minus 200. So the quick mental calculation is 3(00) X distance minus 200. Very quickly I can work out my profile at 7 miles which is 3 X 7 minus 200 = 1900 feet.

I can fly the approach and not need to constantly refer to the chart to check my profile. You cannot do this with a GPS approach since the distance counts down to the FAF and then the missed approach point. You need to refer to the chart to check your profile. This is why I and other people I know don't like GPS approaches.

It seems that in Oz that you use the 3 degree or 318'/nm profile however you can still closely approximate with that slope as well using the technique I mention.

The GPS approach flown single pilot in dirty weather can be hard work, harder than it should or need to be.

[ForkTailedDrKiller]

I know exactly what you are getting at!

Fortunately I can't do mental calculations (never could!) so I don't over complicate my life with that stuff.

Our GPS/RNAV approaches are mostly 3 degree descents, the same as the ILS, and the charts are set up to show a 3 degree descent to either the MDA or the threshold. So all I have to do is note the descent point in the approach and set the aeroplane up as I would do for an ILS. Drop the gear at the descent point and wander on down to the MDA. I can see where the aeroplane is on the approach in relation to Initial, Final and Missed approach points, and its easy enough to monitor the descent. Real easy if I let "George" fly the approach.

I fly maybe one a week on average. Some in crap weather - admittedly rarely as crap as in NZ (I spent 4 yrs in Palmerston North!).

The GPS approach flown single pilot in dirty weather can be hard work, harder than it should or need to be.

Sorry! Each to his own - but I just can't see it.

Dr :8