Four whites on PAPI: Go around?
Thread Starter
Join Date: Apr 2010
Location: Q
Age: 39
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
Four whites on PAPI: Go around?
Hi, I've been wondering if given the following situation, a pilot should start a go around or not. Let's go:
While on a NPA, after coming out of the clouds, stabilized in speed and configuration, you clearly see the runway and the PAPI indicator, the only problem is, you see four white lights on the PAPI (too high), while keeping 1000 fpm (no more) trying to capture a normal profile towards the runway, based on the PAPI indication. While in this condition, you determine that touchdown will be made on the TDZ.
What do you do? Let's put asside the "my company SOP's say that we should go around" responses, that makes the decision easy, and what I'm trying to know is if there's a technical reason for a go around in that kind of situation, or a technical reason for NOT going around.
Thanks.
While on a NPA, after coming out of the clouds, stabilized in speed and configuration, you clearly see the runway and the PAPI indicator, the only problem is, you see four white lights on the PAPI (too high), while keeping 1000 fpm (no more) trying to capture a normal profile towards the runway, based on the PAPI indication. While in this condition, you determine that touchdown will be made on the TDZ.
What do you do? Let's put asside the "my company SOP's say that we should go around" responses, that makes the decision easy, and what I'm trying to know is if there's a technical reason for a go around in that kind of situation, or a technical reason for NOT going around.
Thanks.
Join Date: Jul 2002
Location: Nearest Bombardier AMO
Posts: 417
Likes: 0
Received 0 Likes
on
0 Posts
I suspect most would go around in accordance with SOP. Leaving that aside for a moment for the sake of the discussion as you ask, you do not specify the altitude at which you are breaking cloud/becoming visual, or the aircraft type/type of operation of your scenario. My point being that I'd suggest that there's a difference between breaking at minimums on a foul day in -for example- a medium jet at max landing-weight, i.e. go-around without hesitation, and, say, a light turpoprop/piston becoming visual at 3000 AGL at a ref of 90, which could arguably be made to fit the profile safely and with room to spare without the undesired unstabilised approach below 500/1000 (VMC/IMC).
Join Date: Aug 2005
Location: fl
Posts: 2,525
Likes: 0
Received 0 Likes
on
0 Posts
Put a little thought in what you do. Are you at 3,000 ft or 1,ooo ft. At 3,000 ft you have options, at 1,ooo you have few. That is why you are the captain, you decided what to do.
Thread Starter
Join Date: Apr 2010
Location: Q
Age: 39
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
Let's say you break off clouds at 2000' AFE, that's when you see the runway and the PAPI and although you are high on the approach, your assessment of the situation tells you that the landing can be made on the TDZ, and in fact, you do, despite having four white lights on the PAPI. You have four white lights until touchdown.
The aircraft can be a B737 or A320, doesn't matter, something in those lines.
Another case: There's a certain airport (real life) that if you follow the PAPI lights, you overfly the threshold at 100' RA. Some pilots say that you should try to have 3 reds and 1 white in order to overfly the threshold at 50' aprox. Others say that you should follow the PAPI light no matter what. There's nothing about this in our SOP's, so that's why I have this question.
Regards.
The aircraft can be a B737 or A320, doesn't matter, something in those lines.
Another case: There's a certain airport (real life) that if you follow the PAPI lights, you overfly the threshold at 100' RA. Some pilots say that you should try to have 3 reds and 1 white in order to overfly the threshold at 50' aprox. Others say that you should follow the PAPI light no matter what. There's nothing about this in our SOP's, so that's why I have this question.
Regards.
Last edited by AlphaFloor27; 27th Mar 2013 at 00:08.
Join Date: Sep 2006
Location: Brighton
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
What's the angle of the NPA and the angle of the papis from your approach plate as they don't always coincide. If you were on profile on the approach then your still on profile. Its not always a great idea to dive for the papis at low level. If your thrust is set and the aircraft is stable and heading for the touchdown zone then why change things to bring the papis inline when you weren't flying a visual in the first place.
Another question from a pilot with little real experience flying planes instead of books.
AlphaFloor
Make it right and land. If you can achieve a reasonable glide path (3 degrees + or - a little), near speed, descent rate < 1000 fpm, and cross the fence at 50'-70', you're golden.
AlphaFloor
Make it right and land. If you can achieve a reasonable glide path (3 degrees + or - a little), near speed, descent rate < 1000 fpm, and cross the fence at 50'-70', you're golden.
Last edited by galaxy flyer; 27th Mar 2013 at 00:23.
Thread Starter
Join Date: Apr 2010
Location: Q
Age: 39
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
The PAPI and the approach angles coincide, 3 degrees. You are definitely high on the approach, both "visually" and according to the PAPI indication, but with a 1000 fpm ROD, you estimate that a touchdown on the TDZ can be made, keeping all others parameters within the stabilized approach concept. In those conditions, you cross the THR at 100', but the touchdown is done within the TDZ, maybe in the final section of it, but still within the TDZ.
Last edited by AlphaFloor27; 27th Mar 2013 at 00:32.
Join Date: May 2000
Location: Seattle
Posts: 3,195
Likes: 0
Received 0 Likes
on
0 Posts
What airplane? How long a runway? How much excess runway do you have over calculated stopping distance?
If you want answers to YOUR question, it helps to complete the scenario by answering the questions of those who might provide the answers.
'4 whites on the PAPI' don't give a complete scenario. 'I'll land at the end of the touchdown zone' doesn't give much more...
If you want answers to YOUR question, it helps to complete the scenario by answering the questions of those who might provide the answers.
'4 whites on the PAPI' don't give a complete scenario. 'I'll land at the end of the touchdown zone' doesn't give much more...
Intruder is quite correct. Breaking out to a icy runway, high and maybe fast, just making the touchdown zone isn't good enough. Break cloud 1200 AGL to a wet runway, probably can make a correction to be "on profile" comfortably. Break out, high and fast at 200' with fog, going around would be a good idea, shouldn't have let it happen. Are you near max landing weight?
This is where experience comes in and should be earned before sitting in a RPT jet transport.
This is where experience comes in and should be earned before sitting in a RPT jet transport.
Thread Starter
Join Date: Apr 2010
Location: Q
Age: 39
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
So far from the answers, I take there's nothing definite on this matter, it just depends on the situation, given SOP's don't say you should go around. That's what I wanted to know.
Wouldn't help to get into too much detail of a particular situation, just wanted to get a general consensus regarding this subject.
Cheers.
Wouldn't help to get into too much detail of a particular situation, just wanted to get a general consensus regarding this subject.
Cheers.
Last edited by AlphaFloor27; 27th Mar 2013 at 02:32.
Join Date: Apr 2010
Location: Home soon
Posts: 0
Likes: 0
Received 0 Likes
on
0 Posts
737Jock
What would you do if there weren't any papi's?
What would you do if there weren't any papi's?
The PAPIS are only one of the available visual aids to maintain a steady profile to touchdown,the angle can vary as long as you maintain stabilised criteria such as rate of descent,touchdown point (within touchdown zone and within the landing diatance you calculated to be a safe touch down distance for the runway lengh and conditions.
I remember my first lesson on papis:
"4 whites:wake up!,4 reds youre about dead!"
In between,it varies with calibration of the papis,some are design for high flight deck such as 747 and a B 737 will see 3 reds 1 white to maintain 3 deg and 1000 feet touchdown aiming point..
So 4 whites is a reference,a visual aid and not a factor for systematically having to go around,but remember,the closer you get in,the least margin you have,so it may be prudent to go around if by 500 ft you are not where you wish or recommended to be in your profile.
Last edited by de facto; 27th Mar 2013 at 03:29.
Join Date: Nov 2006
Location: Tropics
Posts: 359
Likes: 0
Received 0 Likes
on
0 Posts
Say if something happens, a hard landing for example, the whole world will fault you for continuing despite the runway being long, wide... etc, with all factors considered; and the SOPs saying you should go around. They'll point the finger at you, always.
Let's say you break off clouds at 2000' AFE, that's when you see the runway and the PAPI and although you are high on the approach, your assessment of the situation tells you that the landing can be made on the TDZ, and in fact, you do, despite having four white lights on the PAPI. You have four white lights until touchdown.
As ever the devil is in the detail, most SOPs require a stabilised approach, and they define the criteria. I would suggest that if at 500' AFE, (in VMC) you are still looking at 4 whites then Go-Around.
Join Date: Mar 2005
Location: Uh... Where was I?
Posts: 1,338
Likes: 0
Received 0 Likes
on
0 Posts
There is two concepts to consider, here:
1st, the concept of being able to land. You will go around at MDA if you don't have the required visual cues or if you have them but you cannot make a safe landing. In the situation you describe, you can make a safe landing, it seems..
but...
2nd, the concept of stabilized approach. In IMC, as per ICAO PANS OPS and most regulations, you have to be stabilized by 1,000 ft in IMC. In VMC 500. In this case I assume IMC, so if you happen to come out of clouds near minimums and you have 4 whites, you seem kind of unstabilized, because as you say, you are keeping a high rate of descent and you are still "capturing" the 3º slope. Therefore a Go around is required.
1st, the concept of being able to land. You will go around at MDA if you don't have the required visual cues or if you have them but you cannot make a safe landing. In the situation you describe, you can make a safe landing, it seems..
but...
2nd, the concept of stabilized approach. In IMC, as per ICAO PANS OPS and most regulations, you have to be stabilized by 1,000 ft in IMC. In VMC 500. In this case I assume IMC, so if you happen to come out of clouds near minimums and you have 4 whites, you seem kind of unstabilized, because as you say, you are keeping a high rate of descent and you are still "capturing" the 3º slope. Therefore a Go around is required.
Join Date: Apr 2002
Location: -11`
Posts: 308
Likes: 0
Received 0 Likes
on
0 Posts
Landing in the TDZ does not mean anything in itself.
If you have a 2000 meter rwy and you land in the last bit of the TDZ, you only have 1100 meters left.
The manufacturer's FCOM data on actual landing distance assumes you land 300 meters after the threshold. So before the blocks. Go figure...
Too many variables to give a definite answer.
Go around is always a safe option when in doubt.
If you have a 2000 meter rwy and you land in the last bit of the TDZ, you only have 1100 meters left.
The manufacturer's FCOM data on actual landing distance assumes you land 300 meters after the threshold. So before the blocks. Go figure...
Too many variables to give a definite answer.
Go around is always a safe option when in doubt.
Join Date: Nov 2000
Location: Grobelling through the murk to the sunshine above.
Age: 60
Posts: 562
Likes: 0
Received 0 Likes
on
0 Posts
You are definitely high on the approach, both "visually" and according to the PAPI indication, but with a 1000 fpm ROD, you estimate that a touchdown on the TDZ can be made, keeping all others parameters within the stabilized approach concept. In those conditions, you cross the THR at 100', but the touchdown is done within the TDZ, maybe in the final section of it, but still within the TDZ.
.... it just depends on the situation, given SOP's don't say you should go around
The important thing is how you rectify the situation.
On no account with a modern slippy jet should you stuff the nose down.
Contain the speed first, get all the drag out (if it's not already there) and be ready to anticipate regaining the G/S with the correct approach power. (This is better done with manual throttle so apologies if that is not part of your personal SOP)
On the B757/767 sim it is possible to demonstrate that you can cross the OM (typically 4 miles out) 800' high with 20 flap and no wheels and, by promptly following the above technique, be in the slot by 500'.
On no account with a modern slippy jet should you stuff the nose down.
Contain the speed first, get all the drag out (if it's not already there) and be ready to anticipate regaining the G/S with the correct approach power. (This is better done with manual throttle so apologies if that is not part of your personal SOP)
On the B757/767 sim it is possible to demonstrate that you can cross the OM (typically 4 miles out) 800' high with 20 flap and no wheels and, by promptly following the above technique, be in the slot by 500'.
Last edited by scotbill; 27th Mar 2013 at 10:19.