GPS approach have you flown one yet ?
Grandpa Aerotart
How easy would it have been handflying the same approach with a more basic GPS and no MFD?
Or should an MFD and Stec 55X be madatory for GPS NPAs?
My point is they could have been designed better/safer than they have been....not that GPS NPAs are not better than an NDB approach.
Humans are fallible...in my view two pilots and their passengers have already died because a two pilot crew without an autopilot as capable as yours (or any at all apparently..and legally) quite probably were confused about which segment of the approach they were on in very bad weather and with high terrain below them. One crew member, the copilot, was alledgedly not qualified for GPS NPAs.
The holes in the cheese all lined up and a lot of people died. In my view one hole was the design criteria of the approach.
Approaches are designed very simply...NDBs, VORs and ILSs are all very simple manouvers....GPS NPAs are not as simple as the should be and, in fact, the design flies in the face of historic approach design. That is the entire final descent referenced to ONE point in space.
Yes if the FO was trained properly it may not have happened.
Yes if they had a modern digital autopilot it may not have happened.
Equally if the approach was designed differently it may not have happened. I think actually it would not have happened because the approach would have been so similar to all the other types of approaches the captain was experienced with he would have been SIGNIFICANTLY less likely to become confused about where he was in relation to the terrain and descent profile.
IFR pilots have been conditioned for decades to seeing the DME distance decrease to one minimum value once....not decreasing to zero 4 times.
It is just a hole that doesn't need to be there. In the big bad world which of the above factors do you think can be corrected easiest.
Crew training?
Aircraft systems fitment in an aging fleet?
Design of the approach?
Or should an MFD and Stec 55X be madatory for GPS NPAs?
My point is they could have been designed better/safer than they have been....not that GPS NPAs are not better than an NDB approach.
Humans are fallible...in my view two pilots and their passengers have already died because a two pilot crew without an autopilot as capable as yours (or any at all apparently..and legally) quite probably were confused about which segment of the approach they were on in very bad weather and with high terrain below them. One crew member, the copilot, was alledgedly not qualified for GPS NPAs.
The holes in the cheese all lined up and a lot of people died. In my view one hole was the design criteria of the approach.
Approaches are designed very simply...NDBs, VORs and ILSs are all very simple manouvers....GPS NPAs are not as simple as the should be and, in fact, the design flies in the face of historic approach design. That is the entire final descent referenced to ONE point in space.
Yes if the FO was trained properly it may not have happened.
Yes if they had a modern digital autopilot it may not have happened.
Equally if the approach was designed differently it may not have happened. I think actually it would not have happened because the approach would have been so similar to all the other types of approaches the captain was experienced with he would have been SIGNIFICANTLY less likely to become confused about where he was in relation to the terrain and descent profile.
IFR pilots have been conditioned for decades to seeing the DME distance decrease to one minimum value once....not decreasing to zero 4 times.
It is just a hole that doesn't need to be there. In the big bad world which of the above factors do you think can be corrected easiest.
Crew training?
Aircraft systems fitment in an aging fleet?
Design of the approach?
Join Date: Jun 2003
Location: EuroGA.org
Posts: 13,787
Likes: 0
Received 0 Likes
on
0 Posts
Chimbu
I don't think we disagree.
But you aren't comparing like for like.
If you compare flying say
a) an NDB/DME or VOR/DME or LOC/DME approach, using a plain CDI/HSI and nothing else that provides any 2D situational awareness, and DME reads zero at the MAP
with
b) a GPS approach, using some weird old GPS driving a CDI/HSI with no moving map so there is nothing else that provides any 2D situational awareness
and you get the pilot to fly a multiple stepdown approach, then I agree that a) has less to go wrong than b) simply because with a) there are no waypoints to keep track of; you watch the DME reading.
But is this realistic? I suspect there are a lot of commercial planes (especially the knackered old turboprop cargo sort of stuff) that have some knackered old 1995 Trimble that has no moving map, but that isn't realistic in today's GA scene. I don't think anybody has made an IFR GPS for GA without a moving map, for 5-10 years.
And a moving map changes everything, totally. You get situational awareness handed to you on a plate. This is itself unusual in commercial aviation; an ATP with say 30 years' experience may well have never flown behind a moving map.
As regards flying that GPS approach I mentioned manually, I am sure I could. Nothing like as accurately, but one has to test all the aircraft systems one by one, so I fly some approaches coupled, some with the flight director, and some on the HSI. I could not legally land off that GPS one (N-reg are banned) so I landed on a NDB/DME one.
But if the sh*t hit the fan and the workload went through the roof (due to some emergency for example) the autopilot would be ON that instant and I would go for a coupled approach every time. And so should you
So the capability must be tested regularly.
I don't think we disagree.
But you aren't comparing like for like.
If you compare flying say
a) an NDB/DME or VOR/DME or LOC/DME approach, using a plain CDI/HSI and nothing else that provides any 2D situational awareness, and DME reads zero at the MAP
with
b) a GPS approach, using some weird old GPS driving a CDI/HSI with no moving map so there is nothing else that provides any 2D situational awareness
and you get the pilot to fly a multiple stepdown approach, then I agree that a) has less to go wrong than b) simply because with a) there are no waypoints to keep track of; you watch the DME reading.
But is this realistic? I suspect there are a lot of commercial planes (especially the knackered old turboprop cargo sort of stuff) that have some knackered old 1995 Trimble that has no moving map, but that isn't realistic in today's GA scene. I don't think anybody has made an IFR GPS for GA without a moving map, for 5-10 years.
And a moving map changes everything, totally. You get situational awareness handed to you on a plate. This is itself unusual in commercial aviation; an ATP with say 30 years' experience may well have never flown behind a moving map.
As regards flying that GPS approach I mentioned manually, I am sure I could. Nothing like as accurately, but one has to test all the aircraft systems one by one, so I fly some approaches coupled, some with the flight director, and some on the HSI. I could not legally land off that GPS one (N-reg are banned) so I landed on a NDB/DME one.
But if the sh*t hit the fan and the workload went through the roof (due to some emergency for example) the autopilot would be ON that instant and I would go for a coupled approach every time. And so should you
So the capability must be tested regularly.
Join Date: Jun 2003
Location: EuroGA.org
Posts: 13,787
Likes: 0
Received 0 Likes
on
0 Posts
I've flown another GPS approach, again (due to the N-reg ban) at a constant height which placed me outside the ATZ.
This time with no autopilot, all manually on the HSI (didn't use the flight director).
It's suprisingly easy to fly a precise track, even with the GPS/HSI zooming down to the highest (0.3nm full-scale) sensitivity. Very easy to keep the vertical bar to something like 1/20 of full-scale. That's around 20m off track - perfectly acceptable given the generous MDH these approaches have.
Laterally, it's a lot easier to hold than an ILS, although to be fair an ILS gets really sensitive only at the 200ft DH whereas one would not fly a GPS approach below say 600ft MDH.
Of course I would still choose an ILS if there was one on the same runway, and that is more or less the case where GPS approaches exist in Europe.
This time with no autopilot, all manually on the HSI (didn't use the flight director).
It's suprisingly easy to fly a precise track, even with the GPS/HSI zooming down to the highest (0.3nm full-scale) sensitivity. Very easy to keep the vertical bar to something like 1/20 of full-scale. That's around 20m off track - perfectly acceptable given the generous MDH these approaches have.
Laterally, it's a lot easier to hold than an ILS, although to be fair an ILS gets really sensitive only at the 200ft DH whereas one would not fly a GPS approach below say 600ft MDH.
Of course I would still choose an ILS if there was one on the same runway, and that is more or less the case where GPS approaches exist in Europe.
Join Date: Mar 2002
Location: Euroland
Posts: 2,814
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Chimbu chuckles
IFR pilots have been conditioned for decades to seeing the DME distance decrease to one minimum value once....not decreasing to zero 4 times.
It is just a hole that doesn't need to be there. In the big bad world which of the above factors do you think can be corrected easiest.
Crew training?
Aircraft systems fitment in an aging fleet?
Design of the approach?
It is just a hole that doesn't need to be there. In the big bad world which of the above factors do you think can be corrected easiest.
Crew training?
Aircraft systems fitment in an aging fleet?
Design of the approach?
IFR pilots have for years been trained to follow the procedure depicted on the approach plate.
In some cases the DME reduces as one approaches the MAP and in others it is increasing.
Assuming that the DME will reduce towards the MAPT is what caused an aircraft to hit the ground close to the DME station, some miles short of the aerodrome.
Can't remember if it was the Philipines or Guam.
Regards,
DFC
