CAA Approve GPS approaches
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Originally Posted by slim_Slag
Originally Posted by IO504
Obviously a pseudo ILS is safer than doing separate stepdowns
2 - You have a stabilised approach from a long way out, minimizing work
3 - You won't dive through your altitude (re Sir GC's comment)
4 - When you break out you should be able all set up on final on a good glidepath
vs.
1 - You don't have to calculate/check your pseudo glide path is safe if you do a step down approach
2 - You will probably breakout earlier when stepping down
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Certainly many here are totally unfamiliar with the way most GPS approaches are actually flown in the United States.
Now, in my airplane I have a Bendix/King KLN89B, and this unit is an earlier generation IFR approved GPS, with a moving map display, which even today, is just as useful as the newer generation color displays found on Garmin 430/530 series units.
It will be found that, during a normal GPS approach, that the distance to go to the next waypoint (or stepdown fix, if you prefer) is continuously displayed, and from this, you the pilot, can clearly see your position in the approach...WHEREAS, during a normal VOR/DME approach, the total distance from the station is displayed.
So, we can see from the above, that once you have passed one particular waypoint (again, stepdown fix, if you prefer) the display changes to the next waypoint, and the distance to go to that waypoint is then displayed.
IF a pilot is unable to follow this type of approach with GPS equipment as used in the USA, realistically speaking, he/she does NOT deserve to have an instrument rating in the first place.
It is, quite frankly folks, easier than falling off a log.
No mental gymnastics required, just follow the procedure as displayed.
As for pilots of GPS equipped aircraft crashing due to misrepresentation of fixes displayed, I can only think of one, and in this particular case, the pilots were following the VOR/DME procedure, ignoring completely the GPS presentation.
Not too bright.
Now, in my airplane I have a Bendix/King KLN89B, and this unit is an earlier generation IFR approved GPS, with a moving map display, which even today, is just as useful as the newer generation color displays found on Garmin 430/530 series units.
It will be found that, during a normal GPS approach, that the distance to go to the next waypoint (or stepdown fix, if you prefer) is continuously displayed, and from this, you the pilot, can clearly see your position in the approach...WHEREAS, during a normal VOR/DME approach, the total distance from the station is displayed.
So, we can see from the above, that once you have passed one particular waypoint (again, stepdown fix, if you prefer) the display changes to the next waypoint, and the distance to go to that waypoint is then displayed.
IF a pilot is unable to follow this type of approach with GPS equipment as used in the USA, realistically speaking, he/she does NOT deserve to have an instrument rating in the first place.
It is, quite frankly folks, easier than falling off a log.
No mental gymnastics required, just follow the procedure as displayed.
As for pilots of GPS equipped aircraft crashing due to misrepresentation of fixes displayed, I can only think of one, and in this particular case, the pilots were following the VOR/DME procedure, ignoring completely the GPS presentation.
Not too bright.
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I agree with 411a and MMF, of course. Flying the approach is dead easy.
The bit where different units differ is the way the missed approach part is handled.
You don't (necessarily) get automatic waypoint sequencing after the MAP. I believe the KLN94 offers the next waypoint after the MAP (which will usually be somewhere straight ahead) and you have to press DCT ENTER to select that.
There is also plenty of older stuff around that doesn't display arcs and thus doesn't display SIDs/STARs in a meaningful manner. I went on a manufacturer course on this once.
The bit where different units differ is the way the missed approach part is handled.
You don't (necessarily) get automatic waypoint sequencing after the MAP. I believe the KLN94 offers the next waypoint after the MAP (which will usually be somewhere straight ahead) and you have to press DCT ENTER to select that.
There is also plenty of older stuff around that doesn't display arcs and thus doesn't display SIDs/STARs in a meaningful manner. I went on a manufacturer course on this once.
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slim_slag brings up an interesting point about 'early' descents.
I have been flying for over forty years professionaly, in a variety of airplanes, and from the earliest days, have used the step down method of flying non- precision approaches.
This does NOT require that you absolutley dive toward the next fix, and thereafter fly level for a protracted period of time.
It is so very easy to establish a (roughly) 700-800 ft/min rate of descent, and by doing this, arrive at the next step down fix at right about the correct altitude.
However, in order to actually be able to land the airplane, you positively need the MAXIMUM time at the MDA, to see the airport, and this is especially important for straight in approaches, but it is also important for circling as well.
Don't dive at the ground, use that 700-800 ft/min rate of descent, and 9 times out of ten, it works out as advertised.
In big airliners or small GA airplanes.
It ain't especially hard, folks, it just takes discipline.
I0540 also brings up an interesting point.
Clearly, not all GPS units are the same.
Each requires a certain sequence of 'button pushing' to achieve the desired results...and, many times that operating manual is not the clearest form of information.
What is required is...practise, with operating the unit prior to actually leaving the ground.
And then, fly in VFR weather for awhile with a safety pilot, to get the particular units sequence down pat, prior to sticking your nose in any cloud.
Properly used, these IFR GPS units are a HUGE increase in overall safety.
I have been flying for over forty years professionaly, in a variety of airplanes, and from the earliest days, have used the step down method of flying non- precision approaches.
This does NOT require that you absolutley dive toward the next fix, and thereafter fly level for a protracted period of time.
It is so very easy to establish a (roughly) 700-800 ft/min rate of descent, and by doing this, arrive at the next step down fix at right about the correct altitude.
However, in order to actually be able to land the airplane, you positively need the MAXIMUM time at the MDA, to see the airport, and this is especially important for straight in approaches, but it is also important for circling as well.
Don't dive at the ground, use that 700-800 ft/min rate of descent, and 9 times out of ten, it works out as advertised.
In big airliners or small GA airplanes.
It ain't especially hard, folks, it just takes discipline.
I0540 also brings up an interesting point.
Clearly, not all GPS units are the same.
Each requires a certain sequence of 'button pushing' to achieve the desired results...and, many times that operating manual is not the clearest form of information.
What is required is...practise, with operating the unit prior to actually leaving the ground.
And then, fly in VFR weather for awhile with a safety pilot, to get the particular units sequence down pat, prior to sticking your nose in any cloud.
Properly used, these IFR GPS units are a HUGE increase in overall safety.
