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SWA 737 overrun at BUR - Dec 6 2018

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SWA 737 overrun at BUR - Dec 6 2018

Old 13th Dec 2018, 07:20
  #101 (permalink)  
 
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No aircraft manufacturer or Company SOP suggests duck under technique nor does certified landing performance expects a pilot to do that. So there is simply no justification narrow body, wide body, turbo prop all included. If there is a runway which requires that then that type of aircraft should not be operating there. It is not proper to suggest unsafe alternate techniques to increase landing run for the present SWA case. If the touchdown was at proper distance then it will prove that the landing should not have been affected with so many limiting variable environmental and RW lenth factors
You are not giving us anything new. I think most pilots are aware of their type's "air distance" which the landing distance is predicated on. 455 m for the 737. The runway aiming point is 300 m for runways shorter than 2400 m, 450 m for longer runways. The TDZ lights (if installed) extend to 900 m or half the runway length, whichever is shorter. These are ICAO standards and taken from memory, if they're wrong., I would think BUR is close to it anyway. My point is, it's purely academic. Don't come and tell me you touch down half way down a wet runway 8, with 10 kts tail, and tell me it was a good landing cause it was in the TDZ!!! (not saying they did).

Do you ever operate on contaminated? Slush, dry snow, sanded, snow on ice... a combination of them all? The calculations show we are legal, but we all know the braking action is a best guess. My experience with 737 is the brakes are doing a great job. We often stop much shorter than the app tells us. But 1800 m in a 737-800 with contamination and a river at the far end is not the place to be "academic".
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Old 13th Dec 2018, 07:31
  #102 (permalink)  
 
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For the sake of a good discussion, a question for those who are categorically against touching down a bit early- If on a bad wx day, your company builds a flightplan with the absolute legal minimum fuel, do you always accept fuel shown on the flightplan?
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Old 13th Dec 2018, 11:07
  #103 (permalink)  

Only half a speed-brake
 
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Oh come on, you can do better than that C/A.

Different game: On your A/C type for an ILS approach, when everything is perfectly aligned, the RA auto-calls "50" when the pilot seat is over the THR markings (piano keys) - TRUE or FALSE? (it's not an open book question). Close your eyes and say it .... ?

Yet to give you an answer, I am sure everyone does a bit more pushing on the short runways and tries to tweak it closer to the tarmac edge.

The point made is the correct normal technique will suffice: 291 m aim-point, 450 m (-50/+25) touch-down point, Vref to Vref -5. The best a pilot can do to be safe and effective on short runways is to practice on the longer ones to get that skill perfected.

(clickable image)

This is where I earned my first stripes - LDA 3400ish. The rubber marks paint a picture where many of the pilots are in true need of a different technique for the shorter runways. No denying that.

Maybe we can see a picture from your side of the world.

Last edited by FlightDetent; 13th Dec 2018 at 11:23.
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Old 13th Dec 2018, 11:52
  #104 (permalink)  
 
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If you land the aircraft in the way the Boeing, training manual specifies you will attain the required landing performance every time. No need to have a separate short field or long runway technique. Do it the same every time and the performance requirements will be met. Now, there is room for error and the wiggle room the performance calculations give you is less on wet runways and almost nothing on contaminated. You’ve also got to make 100% certain the auto speed brake deploys, the auto brakes activate, and the reversers which may normally only be brought to idle are used straight away, at maximum reverse. If you land long and/or one of the autobrake, speedbrake or reversers are not activated, an overrun may well be on the cards. Read through the NTSB reports on the AA 757 overrun, at Vale, the SWA, Midway overrun and the Eastern, La Guardia 737 overrun to see how a short runway and a braking system failure or late selection can cause trouble fast.
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Old 13th Dec 2018, 12:15
  #105 (permalink)  
 
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If you land the aircraft in the way the Boeing, training manual specifies you will attain the required landing performance every time. No need to have a separate short field or long runway technique.
Not necessairly on contaminated, as those who have operated on them can testify.
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Old 13th Dec 2018, 12:31
  #106 (permalink)  
 
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I suppose you are right 172 driver. The biggest problem with contaminated runways is that when you are in dynamic situation i.e it’s starting to snow or raining heavily it can be hard to know when the runway is contaminated and what the braking actions are. It’s not not like there is someone measuring the contaminant depth or checking the braking action every few seconds. Pilot, reports are not reliable either. Maybe the SWA pilots, thought that the braking action was better than it truly was.

I don’t know much about performance as a subject, other that it is kind of vague.
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Old 13th Dec 2018, 12:48
  #107 (permalink)  
 
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The biggest problem with contaminated runways is that when you are in dynamic situation i.e it’s starting to snow or raining heavily it can be hard to know when the runway is contaminated and what the braking actions are
Exactly that. It's not an exact science. And we do divert when the numbers are really down, but we can't divert for every reported reduction of braking action. So where do we draw the line in the sand? Pilot discretion. However, one tool you have at your disposal is is to drop down a bit below your normal descent path and touchdown earlier than what the performance app assumes - i.e. " duck under". Done with caution, not a big deal on the 737. I won't speak for longer bodies. However, that discussion was equivalent to opening a can of worms.
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Old 13th Dec 2018, 14:01
  #108 (permalink)  
 
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Originally Posted by FlightDetent View Post
Oh come on, you can do better than that C/A.

Different game: On your A/C type for an ILS approach, when everything is perfectly aligned, the RA auto-calls "50" when the pilot seat is over the THR markings (piano keys) - TRUE or FALSE? (it's not an open book question). Close your eyes and say it .... ?

Yet to give you an answer, I am sure everyone does a bit more pushing on the short runways and tries to tweak it closer to the tarmac edge.

The point made is the correct normal technique will suffice: 291 m aim-point, 450 m (-50/+25) touch-down point, Vref to Vref -5. The best a pilot can do to be safe and effective on short runways is to practice on the longer ones to get that skill perfected.

(clickable image)

This is where I earned my first stripes - LDA 3400ish. The rubber marks paint a picture where many of the pilots are in true need of a different technique for the shorter runways. No denying that.

Maybe we can see a picture from your side of the world.

As you can see here, many folks going into LGA prefer to add a buffer to the landing distance available. Couldn't find a similar picture for DCA.
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Old 13th Dec 2018, 14:50
  #109 (permalink)  

Only half a speed-brake
 
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In response to to 172

A cautious duck under as you describe it (= closer choice of the aiming point for purists) is surely not a sin. 172 we are in agreement it is part of the duty even, to make sure all the odds are in our favour.

My aeroplane on the G/S has 30 ft RA margin over the THR, leaving
- 10' for me not being accurate
- 10' for a gust or shear
- 10' before the making news.

Geometrically, G/S intersects 291 meters deep. To keep at least 20' screen, aiming for the 200 m point is the shortest sensible option. The extra 90 meters is not a negligible distance, sure. Still, it is a straw-man. Only the touchdown point and speed count. Both are defined by the speed vector at 50' more or less, bit by individual flare technique and largely by correct thrust reduction for the landing.

If we point the A/C steadily to the correct point (not short) between 150-50 feet AGL, cross the THR on the G/S and retard the thrust to idle by 15', the proper touchdown distance is always assured. Mr. Newton and mother Earth will take care of that.

One way to mess things up is to fiddle with thrust through a non-standard flare, having decided at 70' to do something creative. Not aiming short(er) never caused an overrun.
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Old 13th Dec 2018, 16:34
  #110 (permalink)  

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Without any real intention, just a few pictures.
- the red dot is 3° intersect, i.e. instrument aiming point
- the blue line is the PAPI reference
- the green field is 400-475 meters from THR

(There are some unusual things about Burbank)

Burbank 8


Regan 19


LaGuardia 22


Kingston 19


Toronto 24L


Sweet Home 24

Last edited by FlightDetent; 13th Dec 2018 at 17:08.
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Old 13th Dec 2018, 17:26
  #111 (permalink)  
 
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Let's not kid ourselves, shorter runways require different flying. Aim point and touchdown take a higher priority vs trying to land smoother. The touchdown zone where the landing is required is 1/3 of the landing distance or the first 3000'. With a 5802' runway the requirement to be on the ground is 1930'. How many regular landings go around if they're not down by the 2000' mark? None. Shorten the runway to 5100' and the go-around requirement reduces to 1700'. How many normal runway landings go-around if they're not on the runway by 1700' from the threshold? Answer: none.
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Old 13th Dec 2018, 18:33
  #112 (permalink)  

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Shorter runways require correct flying, whereas the long runways don't, absolutely.

Full points on the priorities, not so much about the touchdown zone. Although we say the touch-down zone is the first 1/3 or 3000 ft (shorter of), it is not how the aeroplane should be landed.

Touching down at 3000 ft (1000 meters ffs!) on a 9000 runway is NOT ok. To keep the performance data valid the ILS receiver passes the THR at 50', going for 955 ft (291m) intersect point against the pavement. The normal touchdown ensues around 450 m (1500 ft), anything beyond 600 m is not correctly done. Irrespective of runway length. Sure, we've all done it multiple times and nothing was compromised but it is not playing by the rules.


Somewhere in Germany - pure ICAO Annex 14 standard for runways 1500-2399 m. Four distance markers.
LDA 2180 m of which 1/3 is 730. 5x markers would be appropriate to show the 1/3rd "touchdown" zone.


Last edited by FlightDetent; 13th Dec 2018 at 20:18.
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Old 13th Dec 2018, 19:18
  #113 (permalink)  

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Back on the topic of the SWA over-run itself.

Red point
= nominal 3° slope intersect with pavement (assuming 50' at THR)

Green field
= expected landing area as per FCOM and AFM/performance assumptions

Blue area
= conventional understanding of touchdown zone (1/3rd of the runway here)

Magenta line
= actual position of the PAPI

Note: according to ICAO Annex 14 there should only be 4 distance markers for this runway length.



The crew should fight nails and teeth to use this in their defence. The PAPI will take you 600 feet beyond the proper aiming point, and the last two distance markers on the pavement are nothing but a deathtrap.

Comments?

Last edited by FlightDetent; 13th Dec 2018 at 20:20.
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Old 13th Dec 2018, 20:06
  #114 (permalink)  
 
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On the the charts it notes that VGSI and ILS are not coincident.

VGSI at 3 degrees has 72' TCH
ILS at 3 degrees has 60' TCH.

That extra 12 feet puts you quite a ways down the runway.....228 feet to be exact.

Note: FAA does not use ICAO standards.





Last edited by underfire; 13th Dec 2018 at 20:52.
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Old 13th Dec 2018, 20:19
  #115 (permalink)  
 
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Originally Posted by FlightDetent View Post
Back on the topic of the SWA over-run itself.

Red point
= glide-slope intersect with pavement

Green field
= expected landing zone as per FCOM and AFM/performance assumptions

Blue area
= conventional understanding of touchdown zone (1/3rd of the runway here)

Magenta line
= actual position of the PAPI

Note: according to ICAO Annex 14 there should only be 4 distance markers for this runway length.



The crew should fight nails and teeth to use this in their defence. The PAPI will take you 600 feet beyond the proper aiming point, and the distance markers on the pavement are nothing but a deathtrap.

Comments?
Comments?
I think it is safe to say you have never landed 60 tons of 737-800 on a 1800 m snow covered runway with BA Medium.
When you have done this exercise, please return with your fancy theories and tell us you don’t want as much runway ahead
of you as possible when you touch down.
ONE focus only, get the wheels on the ground as early as possible, very little flare, spoliers, reverse and brakes. STOP.
Breathe.



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Old 13th Dec 2018, 20:27
  #116 (permalink)  
 
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Originally Posted by Underfire
That extra 12 feet puts you quite a ways down the runway.....
Isn't it actually 22' compared to the 50'AGL crossing height assumed for the landing performance? I make that approx 22x 20* = 480' or about 135m reduction in runway available. That takes the effective landing distance down to slightly under 1700m, assuming that you are exactly on the visual slope. Not a lot of runway in the wet on that machine.

A recent report on a over-run near miss in Christchurch shows what effect just a little bit of ponding can do to the braking action: Reduced braking effectiveness during landing involving Boeing 737-800, VH-VOP at Christchurch Airport, New Zealand on 11 May 2015

*3 degrees is 5% = 20 x factor
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Old 13th Dec 2018, 21:10
  #117 (permalink)  
 
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In design, we begin with a 3 degree GS with a 50 TCH. Usually, due to obstacles in the approach, the TCH is raised up. This is not encouraged because of the issues with the lights, markings, and runway length. Some procedures keep the 50 ' TCH and use a higher glideslope..this helps with some of the issues.

Looking at the chart, the ILS and RNAV TCH are both 60. The VGSI is set at 3 degrees with 72 TCH, so if you follow that, you are really long...

This airport is funny, looking at the missed, it requires 340/nm climb rate, tough to do in the heat...the reason? The controlling obstacle in the missed is the folded wings monument to aviation!




Look at SFO, especially after the accident, multiple TCH

Last edited by underfire; 13th Dec 2018 at 21:36.
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Old 13th Dec 2018, 21:23
  #118 (permalink)  
 
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Having a senior moment here gents. On Jepp charts, is the TCH based on the GS or PAPI?
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Old 13th Dec 2018, 21:38
  #119 (permalink)  
 
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Glideslope
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Old 13th Dec 2018, 21:38
  #120 (permalink)  
 
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at BUR both the GS and PAPI use a 3 degree GPA....

The TCH places the GPA height at the Threshold.
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