Strange SOP on how to land a 737

[Centaurus]

I never fail to wonder how different operators have widely varying SOP for a simple manuever.

No names of course but a SE Asian operator has a published SOP that on becoming visual on an ILS, the electronic glide slope must be abandoned and the PAPI lights followed. The fact the PAPI siting is often different to the glide slope ground transmitter due to various technical reasons, means a pilot could be flying a perfectly stable coupled approach then on seeing the PAPI he has to now to follow the PAPI which could have a siting variance. The stated theory is that the ILS glide slope is not accurate below a Cat 1 DH while the PAPI is purportedly accurate to the flare.

Flight calibration testing of a Cat 1 ILS normally continues below 200 feet to 50 feet to confirm the electronic glide slope is stable below 200 feet. If there is significant stability below 200 ft it would be subject to NOTAM. Any thoughts?

[haughtney1]

It's not just un-named 737 operators Centaurus, there are plenty of others who also mandate this idiocy, having said that, not all ILS's place you on the centreline on a nice 3 degree slope nicely in the slot to touch down in the first 1000 feet, RWY 31 in the Seychelles springs immediately to mind.

[43Inches]

Considering most PAPI at A380 capable airports now is vastly different to the glideslope the (Australian) T-VASIS looks like a much better alternative. That is all aircraft following a PAPI will theoretically touch down at different points depending on eye position, threshold crossing height will vary depending on type. With a T-VASIS you can use dots up or down to fly a constant flight path angle for the same touch down point or TCH. For example a 737 may fly no light deviation for a TCH of 50ft and the A380 would fly 2 lights high and achieve the same approach angle and same TCH. But having a visual approach system that is compatible with the ILS system is just silly isn't it, its better to just make pilots destabilise their approach at 200 ft or less to change flight path to suit the PAPI.

[BOAC]

Quigte honestly ANY attempt to follow a proper glidepath would be welcome, based on what I have seen over the years, be it ILS or Papi/Vasi.

Transferring to 'visual' has much merit and any difference in touchdown point will be irrelevant. will NOT seriously affect the landing PLUS it means you can fly by looking out of the window instead of at the dashboard. PLUS, of course, it is 'universal' wherever visual guidance is in place and works better on an NPA!

[43Inches]

BOAC lets assume you are doing an ILS cat 1 approach at an A380 capable airport or other NPA with higher minima. If you were perfectly on the IFR slope at night with limited cues other than the VASIS when you become visual the PAPI would tell you you are low in most aircraft other than large aircraft. This than requires a change in power and attitude to achieve the new visual landing point. Imagine you were flying a light jet with virtually no difference between eye position and gear track as opposed to an A380. Should you fly level at 100-200 ft to achieve the correct PAPI indication or continue to land below visual slope indication. If you fly a correct approach path and speed, TCH and touchdown point should be natural. What TCH will you achieve if you fly the PAPI for an A380 in a 737? What affect does that have on your landing distance given your TCH is now way higher, do jets now have landing figures for the increased TCH?

[Capn Bloggs]

BOAC, ILS TCH 50ft. Some PAPIs MEHT 71ft. That's a fair bit of bitumen. However, these "big jet" PAPIs are normally on long, long runways where LDA isn't an issue in a "small" jet like a 737.

Changing aimpoints at 200ft is silly idea, though, IMO. On the GS, take a snapshot at 200ft and hold it, if not ease forward a tad to counter the fright factor. :ok:

43inches of T-VASIS: way to go! Unfortunately, the beancounters think otherwise.

[43Inches]

What is worse when a 737 crew sees a PAPI indicating low on a non A380 airstrip do you need to fly up to be safe? or is it indicating for a an A380? how do you know?

[BOAC]

Woha guys and girls - no-one is suggesting that you should not just 'fly' a 'real' visual approach, but the OP question was about flying the ILS glideslope to TCH.

As to all the questions about A380 airports, 43/Bloggs - do you not have a landing briefing which covers PAPI appearance or do you just bowl on in and think - Hmm - more reds than I expected on the PAPIs but, hey ho.............?

In any case, no sensible pilot will 'suddenly' adjust the visual picture on transferring - there is no need. Providing the picture is 'right' you 'point' the ship at where you want to land and that is it, is it not?

It is, however, a moot point - I have lost count of the number of times I have sat and watched both 4 whites and an ILS GP pointer on the cockpit floor as we sail happily past everything, still airborne and a frantic little hand clutching for the reverser levers - aggghhhh!. Not sure what is being 'followed'. Better to concentrate on just getting the lady down at the right place than following x,y or z.

[43Inches]

BOAC do you understand the difference between what a T-VASIS tells you and a PAPI? One is angle of decent, the other is decent path to varying TCH based on cockpit eye position. Flying 2 reds 2 whites on a PAPI maintains a descent angle to the PAPI, good luck calculating TCH. Flying any other combination leads you to the same point at a different angle. Flying different lights on the T-Vasis maintains the same glide slope angle but adjusts the TCH, a very easy calculation. You just have to adjust for eye-position or cockpit level something manufacturers can do easily. Wouldn't it be great to come out the bottom of an ILS and say 1 dot low thats what i expected rather than its all red lets fly up to the PAPI.

[BOAC]

Yes, but I did not mention a T-Vasi!!:confused: The discussion is about PAPI.

[43Inches]

BOAC but what is the point of systems that don't tell the truth, T-VASIS tells a pilot what they need to know, PAPI is a waste of time for accuracy. If you want to land at the best point and use the least runway T-VASIS does it for every aircraft, PAPI only tells you a point on the runway for eye position, for varying cockpit heights where the wheels will touch is the most important.

[BOAC]

If you want to land at the best point and use the least runway T-VASIS does it for every aircraft - lovely! What if there is only a PAPI? Do you have shares in T-VASI Inc?:)

[43Inches]

The reality is that T-VASIS is only at a very few airports and reducing, PAPI is the new reality. But if you are a true aviator you would recognise that great things are often forgoten in favour of cheap things.

[RAT 5]

Have guys forgotten how to land on a runway after a 3 degree approach WITHOUT any glidepath guidance? It is after all a visual approach following he transition. Whatever happened to maintaining the correct perspective. There were, perhaps still are, many rwys without fancy lights. A B737 can get into some very tiny and interesting places. Perhaps the XAA's wouldn't licence them for commercial jet operations with no christmas lights, but then again Mk.1 eyeball should be a pilot's near and dear friend.

[Derfred]

Thanks RAT.

Mk I eyeball below 300 feet.

I don't even look at the PAPI.

[de facto]

If there aint T-PAPI,I aint going:E

[RAT 5]

If there aint T-PAPI,I aint going

You must be a mama's boy.

[Capn Bloggs]

If there aint T-PAPI,I aint going
Good!!! :D

In any case, no sensible pilot will 'suddenly' adjust the visual picture on transferring - there is no need.
That's was the OP's point...

[Boomerang]

Is this 'SOP' maybe in response to the recent finding on false glide slope captures from the Dutch CAA?

[Kefuddle]

No names of course but a SE Asian operator has a published SOP that on becoming visual on an ILS, the electronic glide slope must be abandoned and the PAPI lights followed.
With a very slight change in your description of their procedure that would be a great SOP. Qantas for example, when following the ILS the crew are under instrument or low vis procedures meaning that one guy is heads up and the other must be heads down and monitoring. When visual and the handling pilot calls for 'visual procedures' both pilots are head free the implication being that the ILS guidance is now of secondary importance. This I quite like because it makes it clear by what means the approach is judged and how the responsibilities between the pilots is clearly defined.

If that is how this SE Asia operators procedures pan out then makes sense to me.

[Centaurus]

Qantas for example, when following the ILS the crew are under instrument or low vis procedures meaning that one guy is heads up and the other must be heads down and monitoring

I recall reading a 1970's accident report on a Caravelle (?) that crashed just short of the runway and into the water while approaching to land at Hong Kong Kai Tak airport Runway 31. It was raining very heavily. The captain was flying the approach and instructed his experienced first officer to stay heads down until he (the captain) was confident he could see the runway through the rain affected windscreen. This was not the "monitored" approach as we know it now. The captain was aware of refraction that heavy rain could cause. On the previous leg which may have been into Sung-Shan, Taipei, there had also been very heavy rain and the captain again directed the F/O to remain heads down while the captain landed.

Now this story is from my memory going back in the 1970s so bear with me. At Taipei and landing in heavy rain the captain was scanning as one does between instruments and outside to pick up visual cues early, when he noticed out of the corner of his eye that the F/O was gazing outside instead of being heads down. After landing he discussed this with the F/O and stressed the importance of (in this case) the F/O staying heads down and not to be tempted to glance up either out of curiosity or a survival mode. The point being that if both pilots are peering through a rain affected windscreen at the same time, the approach could become un-stabilised without either pilot being immediately aware of it because they were looking for the runway.

During the approach to Runway 31 Kai Tak, the captain was heads up and also rapidly scanning between flight instruments and a quick glance outside while the F/O was heads down. Around 1000 ft on short final the captain again noticed the F/O looking outside instead of disciplining himself to stay on the clocks. The captain immediately directed the F/O to stay heads down. When the captain saw the runway lights through the heavy rain he concentrated on maintaining a visual approach path but failed to arrest a high sink rate that was occurring and the aircraft flew into the water. At the inquiry the F/O admitted he was also looking at the runway on short final and therefore had missed the increasing sink rate.

He explained that it was all very well to have a SOP directing the PNF to stay heads down until the PF called visual. But that when getting closer to the runway there was an overpowering temptation to see what was going on outside. He succumbed to that temptation and shortly after with both pilots looking outside, they missed the sink rate.

When one pilot is flying on a low visibility rain affected approach it is difficult for him to continually ensure his PNF is staying heads down especially in a wide cockpit. An SOP is all very well, but human nature switches to survival mode and of course there will a compulsion for the heads down pilot to sneak a look up through the windscreen at the last minute on short final. This is especially so in heavy rain with partial visibility through the windscreen and when the phenomenon of rain refraction is present that often gives a false visual horizon.

[slast]

Centaurus, many thanks for pointing out the Thai Hong Kong accident. On looking at that report you're right about the core aspect relevant to this thread, the problem of both being pilots on conflicting visual cues and not reacting to valid instrument information. However your recollection of the actual event isn't quite correct.

The ILS approach started as a "First Officer's sector" with "not too bad" weather, which deteriorated as the approach continued. This caused the (Danish) Captain to say at about 2000 ft. they would instead switch to a "Pilot Monitored Approach" as required by the Scandinavian Airlines/Thai Airways ops manual for "poor weather" approaches. They had not briefed for this and the (Thai) F/O continued as PF but under the impression he would still be doing the landing (possible language problem cited throughout).

At the same time they started getting Precision Approach Monitoring (radar "talkdown") as well, which caused the Captain and F/O to have different understandings of what DH would be applicable (Capt. thought 615', F/O and F/E or panel operator 415').

The F/E called DH at 415ft, but neither pilot seemed to register this, and the Thai Monitored Approach procedure wasn't 100% clear about criteria for the F/O to execute a go-around in the event of the Captain not taking control at DH. There was also confusion about the landing clearance received from the tower.

With both pilots head up and seeking visual cues in very poor visibility in driving rain and turbulence, and the F/O as Pilot flying, the descent rate built up rapidly. They descended well below DH with the Captain taking control and initiating a go-around at about 100ft after sighting the water, but the aircraft struck the sea short of the runway.

The accident cause was put down as "(i) The pilots did not adhere to the Thai Airways procedure for a "Captain monitored" approach in bad visibility; (ii) The Captain did not monitor the approach adequately; (iii) The co-pilot mishandled the aircraft after descending below minimum altitude; downdraughts may have contributed to the height loss which resulted from this mishandling.

There isn't any reference to the previous Taipei experience or the need for the Captain to make sure the F/O stayed head-down - can you recall any other source for this? I'd be interested to see it.

[Centaurus]

There isn't any reference to the previous Taipei experience or the need for the Captain to make sure the F/O stayed head-down - can you recall any other source for this? I'd be interested to see it.

Thanks for the excellent description of the HKG accident. It sounds like almost certainly the same prang that I remember reading about. Leave it with me and I'll search though my files to see where I got my info from.

[Kefuddle]

Centy,
He explained that it was all very well to have a SOP directing the PNF to stay heads down until the PF called visual. But that when getting closer to the runway there was an overpowering temptation to see what was going on outside. He succumbed to that temptation and shortly after with both pilots looking outside, they missed the sink rate.
Regardless of the HKG incident, your view is capable of standing alone. All I can say is "perhaps". I've flow these procedures to mins in stable and unstable conditions I found the procedure works very well, even with Captains reluctant to go-around!!

[cosmo kramer]

FCTM, ILS:
When visual contact with the runway is established, maintain the glide path to the flare.

FCTM, Non precision:
When suitable visual reference is established, maintain the descent path to the flare.

The guys writing a SOP that tells their pilot, to switch profile at minimum, should maybe try and read the FCTM.

Also, what is the procedure for CATII approaches for said company? When breaking out in 100' and having 3 reds on the papi, is it procedure to do a go-around? They must have a lot of diversions. :E

[framer]

I understand what Centaurus is saying but I think it worth pointing out that if you are comfortable on your instruments then the desire to look out isn't overpowering. All the information is there in front of you and shouldn't change much until the flare.

[galdian]

Cosmo

Ah yes - the good old FCTM that seems so ignored by so many!

To note the use of "maintain" glide path/flight path ie. do not adjust your aiming point.

Bear in mind also landing distances in Boeing narrowbody aircraft are predicated on one aiming point only - 1,000ft, I doubt anybody could show any company technical data for OTHER than 1,000ft aiming point.
You want to aim at anything else....and f**k it up....well I suppose your licence, your choice.

As PAPI are configured for larger aircraft understanding and adapting what the PAPI is telling you is all that's required:
- 200ft 2 white/2 red;
- below 200ft "allow" the PAPI to slide onto 3 red;
- below 100ft "allow" the PAPI to slide onto 4 red;
- "50" call passing the threshold

and...almost as if by magic...a stable approach at a 1,000ft aiming point!:ok:

[LNIDA]

At DA you need visual reference to continue (BIG CLUE) or go around, so if you have visual reference you land visually, now this may come as a shock to some, but why would you want to follow glide path?

Framer

We operate into a couple of airfields where the TCH (threshold crossing height) is negative on an ILS !!

So following the glide path at Bardufoss ILS 28 after DA would bury you, the TCH is -25' i.e. 25 feet below the threshold, so at DA you fly visually to the touch down zone.

At DA aim for the touch down zone, if your stable at DA and the PAPI are set for an aircraft with a higher eye crossing height why upset things by adjusting up to the PAPI you will likely bleed speed off and increase the risk of a tail strike

[framer]

We operate into a couple of airfields where the TCH (threshold crossing height) is negative on an ILS !!
Wow that's a new one to me, I take it the ILS is stationed offset in a gully or something? Anyway, if your company SOP was for the PM to remain on the clocks until DA, that would be a pretty comfortable exercise, if your company SOP was to be on them until TCH then no wonder pilots are looking out the window :eek: my point being that you most likely have a company briefing on those airports and that won't include being on instruments until TCH as that would be silly. If it has the PM on instruments only until DA, no problem.
I'm now off to google Bardufoss, sounds cool.

[Centaurus]

RAAF F-111 Belly Landing (http://biggeekdad.com/2013/04/raaf-f-111-belly-landing/)


About five minutes into the 7 minute video of this F-111 doing a belly landing at RAAF Base Amberley you will see a view from a cockpit of an aircraft on short final of the landing runway. It is instructive to note the proliferation of rubber touch down marks starting at the piano keys and more or less averaging touch-downs at the runway 500 feet markers. At civil airports the rubber touchdown marks are usually to be found to average around 1500-2500 ft in from the landing end of the runway. Why the difference between military and civil operations?

[slast]

Any chance you could post a profile of that approach at Bardufoss and your other approach - you said "a couple" ??

[Kefuddle]

https://www.ippc.no/norway_aip2/current/AIP/AD/ENDU/EN_AD_2_ENDU_5-5_en.pdf

[RAT 5]

below 200ft "allow" the PAPI to slide onto 3 red;
- below 100ft "allow" the PAPI to slide onto 4 red;
- "50" call passing the threshold

The PAPI's are offset quite a way to the side of the RWY. I don't now by how many m's they are from the centre line of the rwy, but who the hell should be looking at PAPI"s below 200' on a visual landing? I'm concentrating on the TDZ point in the middle of the rwy.

[seaduck]

In my company we have a line in our OMA, that the PAPIES are unreliable below 200ft. So we fly to 200ft, and then you fly aiming point.

[BOAC]

I'm concentrating on the TDZ point in the middle of the rwy. - probably the most useful post here so far. On a 'CatI' ILS, at the usual 200' DH, the PAPIS/T-VASIS/VASIS/man with red flag are NOT reliable from there on in, and providing you are on GP at 200' you will NOT come to grief just pointing and landing - in any sized thing.

PS I think R5 means "in the middle of the touchdown zone" (unless, of course, he flies for AA....................:D)

[galdian]

Seeing as the initial post was about changing the aiming point all I'm saying is that IF you maintain your initial (nominal) aiming point of 1,000 ft this is what the PAPI's should indicate.

If you go to - and maintain - 2 white/2 red then you have changed your aiming point.

No comment about looking out/looking in etc.

[RAT 5]

I suggest this confusion about what is best to do stems from a coupe of things. First, though, let me throw in the red hot 'circular discussion point' whether you should follow the ILS G.S or PAPI's when visual after an ILS. IMHO it is always the ILS. I've had numerous discussion on line checks with the LTC, even TRE, who quote what they think the HOT or CP wants. My answer always is "which is the autopilot going to follow? Which is flight checked to the lower minima? Which is more stable? etc."
Moving back to the discussion about what to below 200': in the days of 3 bar VASIS they were usually sited at airports with a mix of wide & narrow body a/c. Thus a B737 type flew 2 reds 1 white and the B747's flew what they flew, possible 2 whites 1 red. Remember the length of the VASIS was quite some meters. Now, according to my local XAA flight check chappy, the airport can set the PAPI's to the worse case of their common a/c. Thus with many wide bodies and an equal mix of smaller a/c the PAPI's are likely to be set for the big boys. Thus it is quite common to fly the ILS to DA, B737, and then dribble into 3 reds. Shock horror from F/O who is on the point of screaming "Go Around." If the airport/Jeppeson would inform us about the set-up of the PAPI's i.e. the TDZ distance in, we could make a reasoned pre-approach brief about what to expect. But they don't. Why not? I do not know. Perhaps they should. They do publish THCH. It could be argued that if this is 50' then a B737 could accept 35' and thus, likely, be 3 reds. This is the only info we have published.

What do the A380 drivers see on standard PAPI's? Is it 3W 1R?

[Capn Bloggs]

If the airport/Jeppeson would inform us about the set-up of the PAPI's i.e. the TDZ distance in, we could make a reasoned pre-approach brief about what to expect. But they don't.
They do 'ere. Meht for every PAPI/TVASIS installation in the country is published on the 10-9. Not as easy as giving the actual TDZ distance in but will give a good idea. A simple Excel will give you the distance. Otherwise, look where the PAPI boxes are relative to the 300m markers.

[RAT 5]

What I really meant was, if the PAPI's are set up for wide bodies. If I see the THCT is 50' I assume so. Trigonometry without my old slide rule beyond me.