SWA 737 overrun at BUR - Dec 6 2018 [Archive]

Zeffy

6th Dec 2018, 18:06

https://aviation-safety.net/wikibase/wiki.php?id=219098

Date: 06-DEC-2018
Time: 09:04 LT
Boeing 737-7H4 (WL)
Owner/operator: Southwest Airlines
Registration: N752SW
C/n / msn: 29804/387

Fatalities: Fatalities: 0 / Occupants: 117

Other fatalities: 0

Aircraft damage: Minor

Location: Hollywood Burbank Airport, CA (BUR/KBUR) - United States of America

Phase: Landing

Nature: Domestic Scheduled Passenger

Departure airport: Oakland International Airport, CA (OAK/KOAK)

Destination airport: Hollywood Burbank Airport, CA (BUR/KBUR)

Narrative:
Southwest Airlines flight WN278 from Oakland suffered a runway excursion on landing on runway 08 at Hollywood Burbank Airport. The aircraft was stopped by the Engineered Material Arresting System (EMAS) at the end of the runway. No injuries reported. 117 people on board. Emergency slides deployed for evacuation. Heavy rain at time of landing.

Weather reported about the incident time (1704Z):
KBUR 061715Z 29008KT 1SM +RA BR FEW005 BKN013 OVC031 08/08 A2993 RMK AO2 AIRCRAFT MISHAP P0026 T00830078
KBUR 061653Z 28011KT 1 1/2SM +RA BR FEW004 OVC013 08/08 A2991 RMK AO2 SLP122 P0033 T00830083

Airbubba

6th Dec 2018, 18:33

Not the first time Southwest has overrun runway 8 at BUR. From Y2K in the pre-EMAS era:

https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/938x724/20000305_0_c_1_a30f3cfe25f30f77cb6df3d9aa9591e034620514.jpg

NTSB report on the Y2K overrun:

https://www.ntsb.gov/investigations/AccidentReports/Reports/AAB0204.pdf

aterpster

6th Dec 2018, 18:37

11 knot tailwind!

A0283

6th Dec 2018, 18:46

@SouthwestAir (https://twitter.com/hashtag/FAA?src=hash"#FAA[/url]Statement: Shortly after 9:05 a.m PT today, [/url][url="https://twitter.com/SouthwestAir) Flight 278 rolled off the end of Runway 8 while landing at @fly_BUR (https://twitter.com/fly_BUR) Airport in #Burbank (https://twitter.com/hashtag/Burbank?src=hash), CA, and came to rest in the Engineered Material Arresting System (EMAS). This information is preliminary and may change. 09:50 - 6 dec. 2018.

Note: I dont see the escape slides on the photos ... simple ladder starboard forward ...

tdracer

6th Dec 2018, 19:00

Looks like the EMAS did it's job. Makes you wonder why it's use isn't more widespread...

thcrozier

6th Dec 2018, 20:25

Anyone know anything about the procedure for pulling the plane out of its hole, repairing the EMAS, and getting the runway open again?

Airbubba

6th Dec 2018, 20:32

Looks like the EMAS did it's job. Makes you wonder why it's use isn't more widespread...

Like grooved runways in some countries, I strongly suspect it's a case of NIH (Not Invented Here).

Bizjets seem to be the most common EMAS users and the FAA has found that pilots will sometimes try to take the plane off the side rather than into the EMAS:

FAA Confirms Cases of EMAS Phobia

August 3, 2017

@aviationweek #aviationsafetyhttps://static.wixstatic.com/media/5d1d17_08e8b1bc7a2642ac98e60d48d092aae6~mv2.jpg/v1/fill/w_546,h_308,al_c,lg_1,q_80/5d1d17_08e8b1bc7a2642ac98e60d48d092aae6~mv2.jpg

WASHINGTON—Pilots in some cases appear to be avoiding a special type of crushable concrete designed to gently stop an aircraft from overrunning the end of a runway—a finding that is puzzling to FAA officials.

“Of all the Engineered Material Arresting System (EMAS) saves, there’s a relatively small number where the aircraft curves off to the side,” said James Fee, the FAA’s manager for runway safety, at a recent safety conference sponsored by the Air Line Pilots Association (ALPA). “It is somewhat perplexing.”

First installed in 1994, EMAS is now in place at 106 runway ends at 67 airports that do not have the standard 1,000-ft. runway safety area buffer. Seven more pads are slated to be installed at six additional airports. Although tailored for the traffic mix at each airport, the design standard calls for stopping an aircraft traveling 74 kt. when it first enters the pad, which is as wide as the runway and several hundred feet long.

Khalil Kodsi, the manager of the FAA’s airport-engineering division, said there have been 12 EMAS “saves” to date, the most recent being an arrest in Burbank, California, when a Cessna Citation business jet with two pilots on board overran a runway and stopped in the EMAS pad.

Greg Wooley, vice president of flight operations for ExpressJet Airlines, said in many cases, the reasons have to do with publicity. “Probably 50% of the folks that I talk to say that if it’s going to be a low-energy event where they’d be 30–40 kt. at the end of the runway, [they question whether] they should take the EMAS or take it into the dirt,” Wooley said at the ALPA safety forum. “We don’t want to make the news, and there are some folks that think if you take the EMAS you’re making the news for sure.”

Alternatively, pilots think if they “take the dirt,” they might get “tugged back up onto the asphalt” and not make the news, he said. “That’s something that we’ve got to address and emphasize more—doing the right thing should be applauded and not be shamed,” Wooley said. “People have that fear of having the spotlight on them because they’ve gotten themselves into that situation.”

Another BUR EMAS save in 2006 with Alex Rodriguez' G-II:

https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/1600x1213/1124053_c885920e36a15970238f37cb469c98bb2c098d1d.jpg

ukpilotinca

6th Dec 2018, 20:48

My favourite news quote of the day, from CNN

The FAA implemented a ground stop that kept incoming flights in the air for an extra 45 minutes

ManaAdaSystem

6th Dec 2018, 20:52

https://aviation-safety.net/wikibase/wiki.php?id=219098

Short runway, heavy rain, tailwind. Is the runway grooved?
Not that usual for the -700 to be involved in off piste events, but given the conditions....

BluSdUp

6th Dec 2018, 21:03

Now considering that fact I wonder why they came up with the brilliant idea of doing a 10 kt tailwind landing in driving rain on a 1768meter runway. Short for my 738 not long for a 737-700 , me thinks! Does anyone have the charts?

Now , we need to make a bet on how fast did they go when the nose wheel left Terra firma LDA and entered the Engineered Stuff!!
I say at least 20 kts, so just to make it interesting , I bet they did 35 kts .
That means they would have entered the Highway with a good 10 to 15 kts depending on deceleration.
Totally wild guess from me, but I think they were sliding without much wheel BA as they drifted left dramatically.
TD ,it is all about money, but this time it did pay back, in property and most probably life.
I used to hate tailwind operation , just out of principle and certainly on lesser powered aircraft then the 737.
Intersection takeoffs and tailwind operation is all about money , it has no operational advantage, in principal, and this reminds me to be more on the ball this winter.

TriStar_drvr

6th Dec 2018, 21:25

Runway 8 is the only one with an instrument approach and yes, it is grooved. Circling to another runway would not be an option in that weather.

Sailvi767

6th Dec 2018, 22:25

Runway 8 is the only one with an instrument approach and yes, it is grooved. Circling to another runway would not be an option in that weather.

A divert would certainly have been a option. Hard to imagine a professional crew accepting a 11 knot tailwind on a short runway in driving rain.

Airbubba

6th Dec 2018, 22:35

Southwest 278 was given a report of braking action good 10 minutes earlier from another 737, they were shooting the ILS 8. You have to pop the autopilot off at least 300 feet above the touchdown zone according to the approach plate. The tower reported an area of heavy precipitation right over the airport. Southwest replied 'perfect, thanks'. Final wind given was 270/10. The accident occurred around 1702Z from the liveatc.com tapes.

http://archive-server.liveatc.net/kbur/KBUR3-Gnd-Twr-Dec-06-2018-1630Z.mp3

http://archive-server.liveatc.net/kbur/KBUR3-Gnd-Twr-Dec-06-2018-1700Z.mp3

From overhead pictures of the mishap and the BUR taxi chart, it appears that the EMAS pad is offset from the end of the runway with more crunchy concrete area to the left of the extended runway 8 centerline.

TriStar_drvr

6th Dec 2018, 23:16

A divert would certainly have been a option. Hard to imagine a professional crew accepting a 11 knot tailwind on a short runway in driving rain.

A divert would certainly be an option, but if the airport was above landing minimums and your perfromance calculations indicated the aircraft could be stopped on the runway, would you divert? Hindsight is always 20/20.

Gilmorrie

6th Dec 2018, 23:30

Oakland to Burbank? Ye gods, take a Uber.

tdracer

6th Dec 2018, 23:48

Oakland to Burbank? Ye gods, take a Uber.

Seriously? 360 miles/6 hour drive (and that's assuming traffic doesn't suck, which it usually does) and you'd take Uber?

Deadstick126

6th Dec 2018, 23:54

Seriously? 360 miles/6 hour drive (and that's assuming traffic doesn't suck, which it usually does) and you'd take Uber?
Take a Lyft. We're nicer. https://www.pprune.org/images/icons/laugh.gif

thcrozier

7th Dec 2018, 00:02

I've found flying vs driving between those cities to be a toss up, given the wait times at the airports.

sherburn2LA

7th Dec 2018, 00:46

I have commuted between Burbank and the Bay Area on SW on a more or less weekly basis for the past 13 years which means I have flown about 500 times and driven maybe a dozen times or so. There was one period of over 5 years I didn't drive at all and when I did I remembered why not.

On the original subject RWY 8 downwind is the norm. I wonder how long the touchdown was as the usual technique seems to be smash it on with landings you don't get elsewhere and then stand it on its nose even allowing for a possible LAHSO. Makes for some excitement in my usual seat on the back row.

Because of the terrain and terminal location adjacent the runway 33 and certainly 26 are rarely if ever used. Maybe if you are a helicopter. In my 'unsecure' spam can 15 was the only option as they think you will be contaminating the secure area even taxiing near the terminal at the end of 8.

machtuk

7th Dec 2018, 00:57

Looks like the EMAS did it's job. Makes you wonder why it's use isn't more widespread...

$$$$$$$$$$$$$$…………... there's your reason why not !

tdracer

7th Dec 2018, 02:04

$$$$$$$$$$$$$$…………... there's your reason why not !

And a hull loss costs how much? Not to mention the potential human costs...

pattern_is_full

7th Dec 2018, 03:50

EMAS is an expense to the airport or the city/authority. A hull loss doesn't cost them anything - that is a cost to the airline or its insurer or the leasing co., or whoever.

Different pots of money controlled by different people and entirely separate budgets.

Unless airlines want to pay for their own EMAS installations at difficult airports they serve. Or threaten to stop service unless the airport pays for EMAS. Or lobby the FAA or equivalent regulators to lean on the airports to do it.

73qanda

7th Dec 2018, 03:53

A divert would certainly be an option, but if the airport was above landing minimums and your perfromance calculations indicated the aircraft could be stopped on the runway, would you divert?
Yes I would in some circumstances TriStar.
This SAFO is important,all crew should have thought about the practical implications of it.
Subject: Turbojet Braking Performance on Wet Runways
Purpose: This SAFO warns airplane operators and pilots that the advisory data for wet runway landings
may not provide a safe stopping margin under all conditions.
Background: Landing overruns which occur on wet runways typically involve multiple contributing factors such as long touchdown, improper use of deceleration devices, tailwind and less available friction than expected. Several recent runway landing incidents/accidents have raised concerns with wet runway stopping performance assumptions. Analysis of the stopping data from these incidents/accidents indicates the braking coefficient of friction in each case was significantly lower than expected for a wet runway as defined by the Federal Aviation Administration (FAA) in Federal Air Regulation (FAR) 25.109 and Advisory Circular (AC) 25-7C methods. These incidents/accidents occurred on both grooved and un- grooved or non-Porous Friction Course overlay (PFC) runways. The data indicates that applying a 15% safety margin to wet runway time-of-arrival advisory data as, recommended by SAFO 06012, may be inadequate in certain wet runway conditions.
Discussion: The root cause of the wet runway stopping performance shortfall is not fully understood at this time; however issues that appear to be contributors are runway conditions such as texture (polished or rubber contaminated surfaces), drainage, puddling in wheel tracks and active precipitation. Analysis of this data indicates that 30 to 40 percent of additional stopping distance may be required in certain cases where the runway is very wet, but not flooded.
For non-grooved or non-PFC runways, experience has shown that wheel braking may be degraded when the runway is very wet. If active moderate or heavy precipitation exists, the operator should consider additional conservatism in their time-of-arrival assessment.
For grooved or PFC runways, experience has shown that wheel braking is degraded when the runway is very wet. If active heavy precipitation exists; the operator should consider additional conservatism in their time-of-arrival assessment.
Possible methods of applying additional conservatism when operating on a runway which experience has shown is degraded when very wet are assuming a braking action of medium or fair when computing time- of-arrival landing performance or increasing the factor applied to the wet runway time-of-arrival landing performance data.
Distributed by: AFS-200 AFS-240
In some cases manufacturers have provided improved performance landing data for grooved/PFC runways. This improved performance grooved/PFC runway landing data should only be used when following any other Airplane Flight Manual (AFM) requirements and/or requirements of section 7 of AC 121-195(d)-1a, “FAR PART 121 OPERATIONAL APPROVALS OF AIRCRAFT WITH OPERATIONAL LANDING PERFORMANCE ON WET RUNWAYS” or equivalent operation specification.
Some of the wet runway braking shortfalls have occurred at US airports where Title 14 of the Code of Federal Regulations (14 CFR) 139 runway design and maintenance standards apply. Operators should be aware that the aforementioned runway design and maintenance standards may not be met in other countries. Many country’s standards for design, construction and maintenance of runways are based on International Civil Aviation Organization (ICAO) Annex 14 runway design and maintenance standards, however they may lack oversight in implementation of these standards. Also, outside of the United States there is often less usage of grooving or PFC overlay which, when present, will normally aid in drainage and mitigate the risk of hydroplaning during active precipitation, thus impacting braking action.
Operators should be aware of the runway maintenance program and wet runway friction capability at the airports to which they operate. Mitigation should be considered at airports where aircraft operators have reason to suspect the runway’s capability of creating good friction while very wet during active precipitation.
As stated initially the other common contributing factors for wet runway excursions are long touchdown, improper application of deceleration devices and tailwind landings. Aircraft operators should review their flight training programs to ensure flight crews are familiar with the assumptions used in creating the data used for the time-of-arrival assessment such as the assumed distance from threshold to touchdown, recommended uses of deceleration devices; aircraft operators should also ensure flight crews are aware of the wind assumed in the original dispatch calculations for the flight. Advisory Circular 91-79A has been recently updated to address these issues and operators should review the guidance contained therein.
In 2015 a committee of manufacturers and regulators will further investigate the issues with wet runway braking performance shortfalls. Airport and aircraft operators will be included in this investigation.
Recommended Action: Directors of safety and directors of operations (Part 121); directors of operations (part 135, and 125), program managers, (Part 91K), and Pilots (Part 91) should take appropriate action within their operation to address the safety concerns with landing performance on wet runways discussed in this SAFO.
Contact: Questions or comments regarding this SAFO should be directed to the Air Transportation, New Program Implementation Branch, AFS-240 at (202) 267-8166.

SquintyMagoo

7th Dec 2018, 05:14

737er

7th Dec 2018, 05:28

Oakland to Burbank? Ye gods, take a Uber.

That’s hilarious. NY City to Baltimore: 187 miles. Oakland to Burbank: 363 miles.

Mark in CA

7th Dec 2018, 08:45

Oakland to Burbank? Ye gods, take a Uber.
The grapevine was snowed in that day! That's where Interstate 5 heads up into a small mountain range before dipping down again into the Los Angeles basin. Travel came to a complete halt.

ManaAdaSystem

7th Dec 2018, 14:31

4 Holer

7th Dec 2018, 15:17

I think he meant Ontario LA California not Oakland....

Doors to Automatic

7th Dec 2018, 20:33

737er

7th Dec 2018, 21:47

Oh dear - a landing in driving rain onto a short runway with an 11kt tailwind followed by the inevitable meeting with Uncle EMAS. When will they ever learn?

Pre-Xmas tea and biscuits without mince pies I fancy :p

How do you figure? Tower reported winds 270/10 to them right before landing. Before that, a higher than a 10 knot tailwind component reported on ATIS would have locked out their landing data numbers and said no can do when they retrieved it,

Callsign Kilo

7th Dec 2018, 21:56

They’ve possibly landed long on a short wet runway with a TWC approaching limits. Could’ve been carrying excess speed (easy to do on an NG) and maybe an inappropriate autobrake setting and possible late application of reverse thrust (think Midway Accident a few years back). All speculation and I sympathise with the guys at the coal face. The aircraft is renowned to bite in similar scenarios. I’ll be interested to see the NTSB report when it becomes available however I do wonder what’s pushing people into accepting approaches on to RW08 with a tailwind at BUR?

ontheklacker

7th Dec 2018, 22:28

737er-
They could have got their legal landing data way before the tailwind picked up...

Kilo-
Theres no other instrument approach available into BUR (vis was 1 mile ish)

Zeffy

7th Dec 2018, 23:43

...interested to see the NTSB report when it becomes available...

Probably not an accident; don't know if or to what extent NTSB will get involved.

NTSB 830 (https://www.ecfr.gov/cgi-bin/retrieveECFR?gp=&SID=11478b3f54ce75f24c11a8ddc8f4f419&mc=true&n=pt49.7.830&r=PART&ty=HTML)

§830.2 Definitions.
As used in this part the following words or phrases are defined as follows:

Aircraft accident means an occurrence associated with the operation of an aircraft which takes place between the time any person boards the aircraft with the intention of flight and all such persons have disembarked, and in which any person suffers death or serious injury, or in which the aircraft receives substantial damage. For purposes of this part, the definition of “aircraft accident” includes “unmanned aircraft accident,” as defined herein...

...Substantial damage means damage or failure which adversely affects the structural strength, performance, or flight characteristics of the aircraft, and which would normally require major repair or replacement of the affected component. Engine failure or damage limited to an engine if only one engine fails or is damaged, bent fairings or cowling, dented skin, small punctured holes in the skin or fabric, ground damage to rotor or propeller blades, and damage to landing gear, wheels, tires, flaps, engine accessories, brakes, or wingtips are not considered “substantial damage” for the purpose of this part.

Airbubba

7th Dec 2018, 23:50

Before that, a higher than a 10 knot tailwind component reported on ATIS would have locked out their landing data numbers and said no can do when they retrieved it,

Is a ten knot tailwind a limitation on a wet runway for the 737 with braking action reported good?

737er

8th Dec 2018, 01:46

Is a ten knot tailwind a limitation on a wet runway for the 737 with braking action reported good?

Yes, sort of, and usually granted for 10 knots tailwind down to braking action 2 (medium to poor) but could be even higher tailwind allowed...that’s the “sort of” because extremely rare exceptions granted for a particular airports. Overriding that of course is yay or nay from performance data calc which have beefy margins built in.

737er

8th Dec 2018, 02:11

737er-
They could have got their legal landing data way before the tailwind picked up...

h)

Well of course they sent for performance ahead of time. Wind 280/11. That’s not an 11 knot tailwind component, it’s 10. So provided the other safety margins were met the performance data would come back with the speeds and stop margins. If it was an 11 knot tailwind component it would be all blanked out..... meaning ya can’t land like that so we ain’t tellin ya nothin..so ya don’t take the bait by accident.

As far as the wind picking up, tower gave them a report on fairly short final of 270/10. 10 knot tailwind component again. Which is probably why they said “perfect”, finger on the TOGA button had it been 260/11 or something. That’s the last wind info they received.

Im just trying to keep it real here regarding the specific issue of did they think they had an 11 knot tailwind component and just landed anyway. To that I’d say it’s monumentally and fantastically implausible.

KBUR 061715Z 29008KT 1SM +RA BR FEW005 BKN013 OVC031 08/08 A2993 RMK AO2 AIRCRAFT MISHAP P0026 T00830078
KBUR 061653Z 28011KT 1 1/2SM +RA BR FEW004 OVC013 08/08 A2991 RMK AO2 SLP122 P0033 T00830083

tdracer

8th Dec 2018, 02:12

Unless airlines want to pay for their own EMAS installations at difficult airports they serve. Or threaten to stop service unless the airport pays for EMAS. Or lobby the FAA or equivalent regulators to lean on the airports to do it.

EMAS at Burbank was partly paid for by an FAA grant after the 2000 Southwest overrun.

73qanda

8th Dec 2018, 10:23

Overriding that of course is yay or nay from performance data calc which have beefy margins built in.
And of course the yay or nay from the PinC.
Whether or not the margins are ‘beefy’ is a matter of opinion. The margin in this case would be around 220m if a 1500ft touchdown was made, that’s 2.8 seconds of float if the surface friction is perfect and the machine performs as advertised. If the surface friction is not as good as the performance software assumes, how many seconds float is it? 2? 1?
The FAA put out a SAFO in 2015 saying that on wet runways the beefy margins can be inadequate due to less than ideal runway surface friction ( rubber build up, water pooling in tyre tracks, surface treatment compounds etc) and they encouraged a ‘nay’ from the PinC even when ‘computer says yes’.

ManaAdaSystem

8th Dec 2018, 12:42

We have 15 knots tailwind limit on our NGs. Sometimes I need to use it.

aterpster

8th Dec 2018, 13:51

We have 15 knots tailwind limit on our NGs. Sometimes I need to use it.
That was a $$$ option on the 767. Don't know whether it's standard on the NG.

ManaAdaSystem

8th Dec 2018, 14:14

I think it’s an option. You pay, you get.
SWA has a 10 knots tailwind limit?

alf5071h

8th Dec 2018, 14:23

Re #35. This event should, must have a public investigation (‘An incident involving circumstances indicating that an accident nearly occurred’ - Annex 13).

Overruns are a top order issue in safety statistics, thus the industry needs all possible feedback to help reduce the number of occurrences.
The aircraft should have been capable of stopping well within the available landing distance; why didn’t it.
More so, why did it enter the overrun area, either ‘engineered’ or as recommended by ICAO, this event has used more than all of the available distance.

A ‘safe’ outcome does not indicate the quality of the decision to land; what were the factors influencing perceptions and decisions (PIREP), the operational safeguards, the assumptions, knowledge base.

If there were technical failures then discuss them openly; over-dependence on reverse thrust, autobrake.
If the conditions were not as ‘broadcast’, measured, assessed, then again we need to know why, particularly after the recommendations and changes from TALPA.

What performance basis does this operator use; manufacturer’s OLD / FOLD, or some third party, is the data digitised, what are the opportunities for miscalculations, … …

edmundronald

8th Dec 2018, 23:12

PJ2

9th Dec 2018, 00:21

edmundronald;

Some FDM/FOQA programs provide this information already.

The flight data requires GPS data in addition to the usual parameters used to calculate air distance from the threshold to the touchdown point.

Determining touchdown point is easy with wheel-spin combined with a couple of other parameters but without wheel spin it can be done using a combination of vertical 'g', longitudinal 'g', spoiler deployment, radio-altitude.

Using standard formula and an airport database, distance remaining as well as distance required at a certain deceleration rate can all be calculated for every landing and fed back in terms of the usual graphs.

The data can be presented on-board but such systems require robust testing & certification if the runway remaining is to be helpful in real-time. Oviously runway contamination plays a significant role...

stilton

9th Dec 2018, 06:41

Might be time for SW to install tail hooks on their aircraft and arresting gear at some of those shorter runways they’re making a habit
of overrunning

They don’t seem to be learning, the culture of hurrying through everything is a real problem, it’s endemic to their entire operation

ATC Watcher

9th Dec 2018, 08:15

interesting comment from Southwest . Spinning the news of fact ? in a photo taken from a drone above the aircraft could leave to believe this .
Southwest Airlines Flight 278 from Oakland to Burbank landed safely and rolled to a stop at the end of a runway. The aircraft rolled into the overrun area known as the Engineered Material Arresting System (EMAS).

safetypee

9th Dec 2018, 09:24

Sailvi767

9th Dec 2018, 11:59

Does SW use FOQA?

alf5071h

9th Dec 2018, 13:03

edmundronald, PJ,

Modern technology and analytical methods are very good at evaluating the past; ‘what happened’, but not so good as explaining ‘why’, or what might be done to reduce the likelihood of further occurrence.
A widespread statistical evaluation might identify local hazards - deteriorating runway surface, poor drainage, on specific runways. However, if the analysis shows a widespread reduction is safety margin (challenges to the regulatory assumptions - ‘work as done is not the same as work as imagined’), then how will the industry react.

Predictive calculation and guidance can help before landing, but this would still be limited by the quality of incoming information - runway braking action, extent of contamination.
Reactive warnings when the aircraft is on the runway should have more accurate data, but if the landing has been well planned, then at best any ‘on the runway actions’ might only suggest the optimum way of using the remaining safety margins, which may already be insufficient.

Many problems have been addressed with revised landing distance calculations (OLD /FOLD) - providing they are used. Additional hazards (lower safety margins) on wet runways have already been identified, but defences remain within the frailties of human evaluation; ground measurements, reporting, choice of performance and levels of braking / reverse.

Heeding ‘Amalberti’s’ views on highly a reliable industry, we must be careful not to disturb the delicate balance which contributes to modern safety.
Beware calls for more EMAS or other technologies, because ‘it saved the day’. Such systems are indicators of upstream problems; these must first be understood and fixed before resorting to ‘engineered’ solutions.
What if EMAS gives crews a subconscious feeling of safety, we ‘drift’ to operate closer to existing (scant) margins of safety; which might become the norm.

aterpster

9th Dec 2018, 13:55

edmundronald, PJ,

Beware calls for more EMAS or other technologies, because ‘it saved the day’. Such systems are indicators of upstream problems; these must first be understood and fixed before resorting to ‘engineered’ solutions.
What if EMAS gives crews a subconscious feeling of safety, we ‘drift’ to operate closer to existing (scant) margins of safety; which might become the norm.

Like drivers over-relying on automobile anti-lock brakes? I don't believe a professional pilot would consider EMAS as a "buffer."

RatherBeFlying

9th Dec 2018, 16:00

The various formulae for landing distance provide margins, but real world surface conditions and variations in touchdown point, weight and speed (seemingly minor approaching the threshold) can blow past those margins.

Instituting larger margins can require lower weights and reduce revenue.

An FOQA program would do well to monitor performance on shorter runways and raise flags when too much margin is getting used.

A really clever FMS could take in groundspeed, weight and expected touchdown point against runway remaining and possibly recommend go around, but at what point in the approach?

Better an EMAS excursion than a failed go around.

Airbubba

9th Dec 2018, 16:45

Like drivers over-relying on automobile anti-lock brakes? I don't believe a professional pilot would consider EMAS as a "buffer."

Indeed, I don't believe EMAS lets you land at a higher weight or with less braking ability. On the other hand, I think a non-EMAS overrun can improve your FAA FAR takeoff numbers if it qualifies as a stopway for an RTO.

Is 737 takeoff and landing performance figured differently from that of the larger Boeing twins? I somehow got that impression from an earlier discussion of the 2005 Southwest MDW overrun.

The various formulae for landing distance provide margins, but real world surface conditions and variations in touchdown point, weight and speed (seemingly minor approaching the threshold) can blow past those margins.

Instituting larger margins can require lower weights and reduce revenue.

An FOQA program would do well to monitor performance on shorter runways and raise flags when too much margin is getting used.

The FOQA program looking over our shoulders supposedly does see things like long landings. If I'm not stable on approach or won't put it on in the touchdown zone even if there are miles of runway left, I can expect a call if I land or no call if I go around (and do it right ;)). Back in the 'good old days' it was considered manly to salvage a botched approach and a lot of metal was bent as a result. I cringe when I think of some of the 'watch this' stunts I saw with paying passengers decades ago on the 727. :eek:

West Coast

9th Dec 2018, 19:56

Now it can be done It would be smart to record each plane's landing weight and stopping distance and windspeed and runway at every landing. Experience would accrue faster and machine learning might save some damage :)

I wouldn't trust numbers under extreme conditions, but then I trained as an engineer, not a pilot.

Edmund

The landing distance aren’t simply AFM data but rather have SAFO distances (fudge factor) factored in from the SWA overrun at the same airport, same runway years ago. The question to me isn’t the data in of itself, rather whether conditions were correctly accounted for and whether the PF did his or her part.

Fursty Ferret

9th Dec 2018, 20:59

. Beware calls for more EMAS or other technologies, because ‘it saved the day’. Such systems are indicators of upstream problems; these must first be understood and fixed before resorting to ‘engineered’ solutions.

Are you mad? What we've just seen is a perfect example of a case which may have led to multiple casualties reduced to little more than dented pride and a new set of gear.

No professional pilot would ever see EMAS as a reason to cut things tighter than is safe - but on the day that someone reports the braking action as "good" when it isn't, I'll be glad that it's there.
ther

West Coast

9th Dec 2018, 21:47

Well said Ferret.

alf5071h

9th Dec 2018, 22:04

aterpster #52 ‘I don’t believe’, but we cannot judge other pilots’ beliefs; this is just another example of the difference between how work should be done - imagined vs work as done - reality, even when we are in the same environment.

Fursty Ferret #56. - (West Coast). Not mad, only an irrational human.
The outcome of an event is not a measure of the hazards which existed before the landing, nor the quality of the decision. The pilots perception and judgement may have been exemplary, yet the outcome was not as expected; the margin of ‘unexpectedness’ should have been contained within current safety margins, but it wasn’t. Why?

EMAS is a ‘fix’ for a runway with insufficient overrun margin, either being less than the ICAO recommendation, or for a specific hazard. It must not be consciously considered as part of the normal operational margins, but subconsciously … who knows.

‘No professional pilot would ever see…’ as above you assume that you know how all pilots will behave in all situations; the decision may not be the conscious ‘seeing’ it, but the subconscious bias from the knowledge that something else exists. Our biased belief is that we are rational, all pilots are rational, irrespective of situation and context; except that most accidents show that these beliefs are misformed.

And re PIREPs, the conditions perceived by the report could have been ‘good’, by their judgement at that time, etc, etc; we don’t know, but having been broadcast, the potential for bias exists, we skip our revised assessment.
With such subjectivity PIREPS are valueless for assessing actual conditions, good or not so (NB use in triggering downgrading assessment TALPA).

PJ2

10th Dec 2018, 00:27

. . . I cringe when I think of some of the 'watch this' stunts I saw with paying passengers decades ago on the 727. :eek:

Believe it or not, a "watch this..." stunt still shows up in the data once in a while. Go figure.

aterpster

10th Dec 2018, 00:34

westhawk

10th Dec 2018, 07:24

When the runway required as calculated under reported conditions approaches the runway available, it just doesn't take much variance in actual conditions to get this sort of outcome. As well, any variance in technique or execution from the assumptions inherent in the performance calculations invalidates the predicted performance to some degree.

With the above in mind, heavy rain associated with a cold front is often accompanied by changing wind direction and velocity during approach. Some amount of shearing in both horizontal and vertical planes is to be expected. This often makes staying on speed and profile during approach somewhat more challenging. The FDR data will shed some light on how much a factor that may have been. I'm just saying that arriving at the TDZ on speed and profile is more challenging in that sort of weather.

I'm also curious as to the location on the airport where the reported wind measurement was taken. They have sensors all over the airport for the purpose of LLWS alerting. While there is no mention of any wind shear advisory having been issued, that does not necessarily mean that the wind at the end of rwy 08 was the same as the wind stated in the report.

It's been many years now since I was based at BUR, but I certainly recall that the winds were always more variable and gusty when out of the West through North. "Normal" winds always seemed to 180/10! KBUR's location with respect to the nearby hills in all quadrants probably has allot to do with the "swirl effect" that so commonly rears it's ugly head when the wind kicks up.

In the three years I flew out of BUR, I only landed during rain storms a couple of times.The rain was only moderate. And that was in a jet that required only about 3/4 of runway distance that a modern 737 at typical loads does. Maybe we were just being overly conservative in some people's view, but we were encouraged by the management to use an 80% (or 125% when looked at the other way) standard and that was before the 15% safety factor was even "a thing". Every pilot has used more runway than they planned to. It's just that most of the time, you don't land if it looks like you're gonna need all of it. So maybe something went way different than planned?

Zeffy

10th Dec 2018, 13:31

“Rolled to a stop !”
Considering that the aircraft stopped half way between the end of the runway and the airport wall / road, that is a lot of energy which has been absorbed. Not a ‘slow speed’ excursion then.

In addition to ‘Lawyers can be found in the grass at the end of the runway’
add
‘The sound of EMAS crunching is like lawyers’ cash registers at full speed.’

Peter Lemme has updated his blog, citing a number of FAA references on overrun prevention as well as design criteria for construction and certification of EMAS:
https://www.satcom.guru/2018/12/stopping-distance.html#more

Near the bottom of the page:
An approximate 110 foot excursion into the EMAS occurred. This suggest that the airplane was travelling less than about 30 kntos.

safetypee

10th Dec 2018, 15:20

Thanks for the link Zeffy ; it presents a credible analysis.
There could be several quibbles in the details; based on the aircraft length the ‘estimated’ distance into EMAS is reasonable, as would be the speed. However the aircraft stopped ~> 50m beyond the threshold (thus faster at runway exit), and the attention getting safety point is that the wall is ~ 80m beyond the threshold - a distance margin equivalent of ‘third’ to ‘home base’ - so no sliding into ‘the wall’ !

The underlying point is that these types of incident should not occur, (the second EMAS at BUR) which indicates an accumulation of several contributing factors, perhaps something common to BUR.

Airbubba

10th Dec 2018, 15:36

Actually this incident is at least the third EMAS save at BUR, A-Rod's G-II in 2006 is missing from some of the lists:

A-Rod on Board Jet That Overruns RunwayThe Associated Press

Saturday, October 14, 2006; 5:36 AM BURBANK, Calif. -- A private jet, carrying Yankees third baseman Alex Rodriguez and six others, overran a runway at Bob Hope Airport on Friday and was brought to a halt by an arresting system. "I spoke to Alex. He's fine," agent Scott Boras said.None of the seven people aboard were injured, federal officials said.The Gulfstream G-II carried five passengers and two crew members, the National Transportation Safety Board said in a statement from Washington, D.C. It departed from Las Vegas earlier in the day.The twin-engine jet was stopped by the Engineered Materials Arresting System, a 200-foot-long stretch of pavement injected with air bubbles designed to collapse under the weight of an aircraft as large as a Boeing 737 jet traveling as fast as 50 knots, airport spokesman Victor Gill said."It came to a pretty quick stop," Gill said.Damage to the aircraft was minor, the NTSB said.

A-Rod on Board Jet That Overruns Runway (http://www.washingtonpost.com/wp-dyn/content/article/2006/10/14/AR2006101400291.html)

alf5071h

10th Dec 2018, 15:48

aterpster #60 ‘I would have either held or gone around.’
I have no problem with that view - as we sit in the sunshine and clear views of hindsight.

The lessons to be learnt will in the difference between our beliefs based on outcome, and the in-situation crew’s beliefs before the approach, and would we have performed any better.

climber314

10th Dec 2018, 16:02

"... was stopped by the Engineered Materials Arresting System, a 200-foot-long stretch of pavement injected with air bubbles designed to collapse under the weight of an aircraft as large as a Boeing 737 jet traveling as fast as 50 knots."

Sounds like he MAY have been doing less than 50 knots? Beyond that it's anyone's guess on waaaay too many variables. :confused:

pattern_is_full

10th Dec 2018, 16:03

"Rolled to a stop" and "crunched to a stop" is a question of semantics and P.R. - but:

- it means the aircraft still retained at least 20% of its touchdown (ground) speed when it ran out of runway.
- "less that about 30 knots" equates to "less than about 35 mph" or "less than about 55 kph."

Not exactly slow.

The NTSB does report on EMAS overruns (cf. Mike Pence/737/LGA and the incident at Yeager/Charleston, WV), so I imagine we'll get good information on the critical possible little details that make the difference - extra speed for gusts, reverser lever jam, failed deployment of spoilers, reverted-rubber planing, etc.

aterpster

11th Dec 2018, 12:46

The NTSB does report on EMAS overruns (cf. Mike Pence/737/LGA and the incident at Yeager/Charleston, WV), so I imagine we'll get good information on the critical possible little details that make the difference - extra speed for gusts, reverser lever jam, failed deployment of spoilers, reverted-rubber planing, etc.
Where we get this good information from? I've read nothing that indicates an NTSB investigation of this overrun.

aterpster

11th Dec 2018, 12:47

alf5071h

11th Dec 2018, 15:08

aterpster, just to round this point off; ’similar situations’ are never the same ;)

Does FSF ALAR CAAG ring any bells ?

meleagertoo

11th Dec 2018, 15:37

On a short runway I'd be minded to accept either heavy rain or a tailwind on limits but not both. That's stacking the odds too much.
Heavy rain implies the possibility of (perhaps locally) contaminated runway - a downwind landing on that is imo a rather risky call.

Meester proach

11th Dec 2018, 16:09

FlyingStone

11th Dec 2018, 17:00

So if the performance data was OK, and you diverted where does that leave you ?

If the margin between LDA and LDR is tight, any sensible company would understand that a tailwind landing onto a short and wet runway wasn't the best idea.

flyingchanges

11th Dec 2018, 17:09

So if the performance data was OK, and you diverted where does that leave you ?

Somewhere else, not off the end.

I view the landing distance numbers as limits, not goals.

172_driver

11th Dec 2018, 17:22

Tailwind is, somewhat, predictable. At least you can run the calculations with some extra knots and see where it leaves you.

Braking action is harder, you don't know what you gonna get until you try. Not sure about California runways but I remember California freeways being quite slippery after months of accumulated dirt followed by rain.

If the undershoot is flat you can duck under to get extra distance. Not everyone's cup of tea, but if you're close to the margain.....

aterpster

11th Dec 2018, 17:34

aterpster, just to round this point off; ’similar situations’ are never the same ;)

Sometimes, sufficiently similar to be a distinction without a difference.

In any case, holding until a red cells moves off the airport is using the "least cost of being wrong" operating philosophy, especially when the tailwind component is at its limit on a short (for jet transports) runway.

misd-agin

11th Dec 2018, 18:43

FMC PROG 2/4 shows the wind components - headwind, tailwind, crosswind. Good reference if you're at the limits and performance is tight.

Vessbot

11th Dec 2018, 19:05

FMC PROG 2/4 shows the wind components - headwind, tailwind, crosswind. Good reference if you're at the limits and performance is tight.

True for X miles away from the airport and Y thousands of feet up. Not at the runway, and (especially in a case like the one being considered) the difference is bound to be big, and variable.

CHfour

11th Dec 2018, 19:48

If the undershoot is flat you can duck under to get extra distance. Not everyone's cup of tea, but if you're close to the margain.....

"Not everyone's cup of tea" Really? If you try that one over on my side of the pond you'll find yourself in the Chief Pilot's office and there won't be any "cup of tea" (or any biscuits for that matter).

73qanda

11th Dec 2018, 21:21

So if the performance data was OK, and you diverted where does that leave you ?
At home or in a hotel having a beer and planning my next holiday.

aterpster

12th Dec 2018, 00:48

At home or in a hotel having a beer and planning my next holiday.

Perhaps even two beers and no hearing in my near future.

vilas

12th Dec 2018, 03:33

If the undershoot is flat you can duck under to get extra distance. Not everyone's cup of tea, but if you're close to the margain... The very fact that you feel that the approch requires something which is not done is a message that you shouldn't be landing there. Short runway, limit tail wind which could easily go over the limit, heavy rain can make the braking action poorer than imagined and control of flight path difficult these are too many variables which can prevent a successful outcome. Not a safe decision to continue the landing.

punkalouver

12th Dec 2018, 03:40

The very fact that you feel that the approch requires something which is not done is a message that you shouldn't be landing there. Short runway, limit tail wind which could easily go over the limit, heavy rain can make the braking action poorer than imagined and control of flight path difficult these are too many variables which can prevent a successful outcome. Not a safe decision to continue the landing.

Different type of operation, but when operating turboprops on short, snow covered remote airstrips years ago, we would almost always intentionally go below the Papi's on short final. No doing so was the higher risk decision.

Sailvi767

12th Dec 2018, 11:42

So if the performance data was OK, and you diverted where does that leave you ?
What could make a difference is local knowledge - does this runway feel like it actually meets the performance normally or not from past experience ?

i think the question is did they have the performance data. Was it updated with the large report of very heavy rain?

Check Airman

12th Dec 2018, 12:29

"Not everyone's cup of tea" Really? If you try that one over on my side of the pond you'll find yourself in the Chief Pilot's office and there won't be any "cup of tea" (or any biscuits for that matter).

For exercising airmanship? In limiting conditions, many ppl will go 3 red on the PAPI at LGA or DCA for example (where your final approach is over water) to get a few extra feet of runway.

aterpster

12th Dec 2018, 12:47

West Coast

12th Dec 2018, 15:10

That's where airmenship comes into play. Long body/heavy perhaps not, narrow body perhaps yes.

meleagertoo

12th Dec 2018, 15:23

Check Airman

12th Dec 2018, 16:02

At LGA if I did that in the 1011, I'd be risking leaving the main gear with the end of the pier.
I've seen Air Canada go to LGA with a 767-300. Not an assignment I'd be hurrying to take. In a narrowbody though, it's quite safe.

172_driver

12th Dec 2018, 16:06

The very fact that you feel that the approch requires something which is not done is a message that you shouldn't be landing there. Short runway, limit tail wind which could easily go over the limit, heavy rain can make the braking action poorer than imagined and control of flight path difficult these are too many variables which can prevent a successful outcome. Not a safe decision to continue the landing.

I am aware of the realities we face in day to day operation, I am assuming we have a valid landing performance. With good visual references and decent knowledge where my under carriage is, I could easily buy myself a couple of hundred feet. What if the undershoot is a displaced threshold? As I said, not everyone's cup of tea.

PEI_3721

12th Dec 2018, 18:04

172, ‘valid landing performance’, no such thing before the landing, only judgement of the unknowns: wet or flooded, what about all the conditions in between. Who measures / reports the conditions; the same with wind, at least +/- 2, so allow +/- 5.
There are few absolutes in flying other than the position where you stop; assumption kill, so concentrate on minimising all other variables, speed, touchdown, bakes, etc … .

FlightDetent

12th Dec 2018, 18:17

There is no short landing technique on a jet this size. Arriving on a decreased angle (3 red) carries higher pitch, more thrust, flatter sink and in general results in a longer touchdown and a higher speed at wheel spin-up. After that, exactly the same sort of people who use the A word to cover gaps in competency or understanding, will immediately claim: see how tight this was? Lucky my skygod decision to go 3 reds, it saved us. Yeah.

Aiming closer to the threshold, steepening the angle in the last stages is more consistent with the intention. Why not, if you know how not to try too hard. Still, reducing geometrical margins on purpose, creating ad-hoc flying techniques, is not the road to a happy retirement.

Land it consistently, as much identical as your everyday approach. Consistency brings predictable results. The touchdown is usually decided between 150 and 50 feet above the ground. If a runway below 2000 m requires a different skill-set, then the one you have on the longer runways is not a correct one. (Placement of PAPI at 400 or 450 m beyond the THR, as opposed to 291 m where the G/S geometric intercept is, WILL create a wrong skill set for those who follow PAPI through to the landing).

The above is a comment to the discussion here, not the incident itself. We will see what the investigation reveals, however, "no landings beyond TDZ markings" is a sound principle. I am curious to see if it did not work in BUR?

One last note: the (lack of) friction over THR markers at the far end, when wet/snowed, is what makes this man uneasy. The last 60 m you might critically need, and as if they did not exist. I suppose everyone had a NW skid during line up once, for no apparent reason.

Airbubba

12th Dec 2018, 18:54

For exercising airmanship? In limiting conditions, many ppl will go 3 red on the PAPI at LGA or DCA for example (where your final approach is over water) to get a few extra feet of runway.

At LGA if I did that in the 1011, I'd be risking leaving the main gear with the end of the pier.

I've seen folks who brief that they want to drop a dot low on the glideslope on short final in widebodies 'since the weather is good'. Is this in the book anywhere? I get the impression that this 'technique' was taught in some Air Force communities (possibly the C-141) years ago.

Check Airman

12th Dec 2018, 19:37

I've seen folks who brief that they want to drop a dot low on the glideslope on short final in widebodies 'since the weather is good'. Is this in the book anywhere? I get the impression that this 'technique' was taught in some Air Force communities (possibly the C-141) years ago.
Not in any book that I've seen, but when landing on a short, wet runway as described above, most of the people I fly with decide against leaving the first thousand feet of the runway behind.

JPJP

12th Dec 2018, 21:01

Not in any book that I've seen, but when landing on a short, wet runway as described above, most of the people I fly with decide against leaving the first thousand feet of the runway behind.

True. Although, more commonly the mains are touching at or just before the 1000 foot markers. Rather that being in mid-flair there.

The expression used was ‘duck under’ (the glide path) on short final. The concept, and the expression were remarkably unpopular with the FAA due to the quite sensible requirement for a stabilsed approach. Ducking under was replaced with the more politically correct term of ‘adjusting the aim point’. Midway, Key West and Burbank are relevant examples.

The Ancient Geek

12th Dec 2018, 22:42

This boils down to how much runway should be behind the touchdown point. When I were a lad, many moons ago, there were no piano keys and we were taught to aim for the numbers. The piano keys were introduced to reduce the incidence of landing short of the paved surface, thus "wasting" part of the runway. All modern aids such as ILS and PAPI are calibrated for the piano keys so the actual landing distance available is less than the runway length which can become an issue for shorter runways in poor weather conditions.
Should we aim shorter for the numbers in these cases ? - I will leave that can of worms for others to chew, the risks have not changed.
Aiming for a firm contact, avoiding greasers, is probably a better idea getting good weight on the wheels ASAP to improve braking.

Fursty Ferret

12th Dec 2018, 22:47

. If a runway below 2000 m requires a different skill-set, than the one you have on the longer runways is not a correct one.

Absolutely spot on.

Vessbot

12th Dec 2018, 23:02

aterpster

13th Dec 2018, 00:25

That's where airmenship comes into play. Long body/heavy perhaps not, narrow body perhaps yes.
Before I flew the 1011 into LGA I briefly flew the DC9-10 into there and many years flew the 727 into there. I wouldn't have considered a duck-under with the 727. The only difference the company touchdown zone for the narrow bodies was 500 feet closer to the threshold then with the 1011.

Capn Bloggs

13th Dec 2018, 03:32

All modern aids such as ILS and PAPI are calibrated for the piano keys Fixed Distance markings so the actual landing distance available is less than the runway length which can become an issue for shorter runways in poor weather conditions.
Apart from the mixup with Piano Keys and the Fixed Distance markings at 1000ft in, this statement isn't right. The LDR takes into account an air-run distance from 50ft to touchdown. In my aeroplane the air-run distance is 455m, almost 1500ft. "Duck under" and use part of that 455m to roll along on if you wish, but the LDR figures assume you will take 455m/1500ft to get the wheels on the ground.

Arriving on a decreased angle (3 red) carries higher pitch, more thrust, flatter sink and in general results in a longer touchdown and a higher speed at wheel spin-up.
I think those effects are overstated. But more importantly, flying three reds allow you to plant it with almost no flare. In my experience, it is the type of flare that is the thing that most-affects the touchdown point. Not that I am suggesting you routinely fly three reds! ;)

vilas

13th Dec 2018, 04:08

172_driver

13th Dec 2018, 07:20

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".

Check Airman

13th Dec 2018, 07:31

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?

FlightDetent

13th Dec 2018, 11:07

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.

https://i.postimg.cc/XXjhTKGP/TDZ-area.jpg (https://postimg.cc/XXjhTKGP) (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.

Fair_Weather_Flyer

13th Dec 2018, 11:52

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.

172_driver

13th Dec 2018, 12:15

Fair_Weather_Flyer

13th Dec 2018, 12:31

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.

172_driver

13th Dec 2018, 12:48

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.

Check Airman

13th Dec 2018, 14:01

FlightDetent

13th Dec 2018, 14:50

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.

FlightDetent

13th Dec 2018, 16:34

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
https://i.postimg.cc/901gt54R/BUR-tdz.jpg (https://postimg.cc/jnwht14t)

Regan 19
https://i.postimg.cc/022B5Q3p/DCA-tdz.png (https://postimg.cc/kDzcfn74)

LaGuardia 22
https://i.postimg.cc/Y96s0mMx/LGA-tdz22.jpg (https://postimg.cc/phdZ1r99)

Kingston 19
https://i.postimg.cc/h40YqxCD/MBJ-tdz.png (https://postimg.cc/mhtjYcfJ)

Toronto 24L
https://i.postimg.cc/rmXHq9Xm/YYZ-tdz.jpg (https://postimages.org/)

Sweet Home 24
https://i.postimg.cc/j2Rk7djY/TDZ-area.jpg (https://postimg.cc/ZBDckm3w)

misd-agin

13th Dec 2018, 17:26

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.

FlightDetent

13th Dec 2018, 18:33

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.

https://i.postimg.cc/ZKYZpJ9c/PAD-tdz.png (https://postimg.cc/jC1Gr04w)

FlightDetent

13th Dec 2018, 19:18

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.

https://i.postimg.cc/05m52n6q/Burbank-distances.png (https://postimg.cc/yW1CLFXf)

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?

underfire

13th Dec 2018, 20:06

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.

https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/608x444/y0gmcwx_806b0772302f0eb68e85d96c6517760d76e2292a.jpg

https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/612x230/taxiway_abbbef3692bc021254045f2a69a22aaebff801f4.jpg

ManaAdaSystem

13th Dec 2018, 20:19

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.

https://i.postimg.cc/05m52n6q/Burbank-distances.png (https://postimg.cc/yW1CLFXf)

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.

CurtainTwitcher

13th Dec 2018, 20:27

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 (https://www.atsb.gov.au/publications/investigation_reports/2015/aair/ao-2015-046/)

*3 degrees is 5% = 20 x factor

underfire

13th Dec 2018, 21:10

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!

https://cimg3.ibsrv.net/gimg/pprune.org-vbulletin/250x333/250px_folded_wings_shrine_portal_89e9277e0722811007f99b9508a 5d9a312184f63.jpg

Look at SFO, especially after the accident, multiple TCH

Check Airman

13th Dec 2018, 21:23

Having a senior moment here gents. On Jepp charts, is the TCH based on the GS or PAPI?

CurtainTwitcher

13th Dec 2018, 21:38

Glideslope

underfire

13th Dec 2018, 21:38

at BUR both the GS and PAPI use a 3 degree GPA....

The TCH places the GPA height at the Threshold.

Capn Bloggs

13th Dec 2018, 22:06

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.
Settle down. If you read Flight Detent's post closely, he is pointing out that the PAPI leads you to a longer touchdown, past the ILS touchdown point. If you were following the PAPI, you'd probably even touchdown past the certification point (455m in).

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'.
In the old days. The current certification numbers (for me at least) are based on touching down at 455m/1490ft in. That extra 500ft might have saved them, eh?

Flight Detent, you need to move your red dot for BUR to a 60ft TCH.

underfire

13th Dec 2018, 23:04

They way they buried themselves 200 feet in, they were coming in real fast...

I would also note that the aiming bars and distance markers are set for the VGSI, not the ILS....(or RNAV/GPS)

misd-agin

13th Dec 2018, 23:07

Wasn't the old data based on "1,000' air distance"? Isn't it now seven seconds, which is a longer distance? All runway behind you based on the expected touchdown point which is used to figure out the required landing distance? 130 kts = 1517'?

Check Airman

13th Dec 2018, 23:21

Glideslope
thanks

Filler

Check Airman

13th Dec 2018, 23:22

Settle down. If you read Flight Detent's post closely, he is pointing out that the PAPI leads you to a longer touchdown, past the ILS touchdown point. If you were following the PAPI, you'd probably even touchdown past the certification point (455m in).

In the old days. The current certification numbers (for me at least) are based on touching down at 455m/1490ft in. That extra 500ft might have saved them, eh?

Flight Detent, you need to move your red dot for BUR to a 60ft TCH.

My last company assumed a touchdown at 1500ft. Always appreciated the buffer.

ManaAdaSystem

14th Dec 2018, 07:36

Settle down. If you read Flight Detent's post closely, he is pointing out that the PAPI leads you to a longer touchdown, past the ILS touchdown point. If you were following the PAPI, you'd probably even touchdown past the certification point (455m in).

In the old days. The current certification numbers (for me at least) are based on touching down at 455m/1490ft in. That extra 500ft might have saved them, eh?

Flight Detent, you need to move your red dot for BUR to a 60ft TCH.

My comment was for all that he posted in this discussion.
What would he do if the landing calculation shows a stopping margin of 10 metres? Land 455 m down the runway because the book tells him to?
I live in the real world where this scenario is not an academic discussion.

73qanda

14th Dec 2018, 08:03

What would he do if the landing calculation shows a stopping margin of 10 metres? Land 455 m down the runway because the book tells him to?
10m?
If the performance calculations suggested that I had 10m margin using maximum manual braking, and the runway was wet or damp, I would divert. The FAA encourages me to :)

ManaAdaSystem

14th Dec 2018, 08:42

aterpster

14th Dec 2018, 13:57

10 m on top of the required margins. Not wet or damp. Snow and ice. BA Medium.
FL40, max manual and Vref +0.
This is the reality on some winter days.
No, 455m air distance is not an option, whatever the books say.

If Burbank were in a snowy/icy climate, I would refuse Runway 8 when covered with ice and snow and a poor braking action report. I'd go for Runway 33, weather permitting. If not, I would divert.

ManaAdaSystem

14th Dec 2018, 16:50

If Burbank were in a snowy/icy climate, I would refuse Runway 8 when covered with ice and snow and a poor braking action report. I'd go for Runway 33, weather permitting. If not, I would divert.

No option to change runway in my example. Calculation shows the landing is doable. Divert and put 150 pax in a hotel or land and have a beer before bedtime?
Would you land and insist on 455 m air distance, or put the wheels as close inside the threshold as possible?
I tell you, I see four red lights every time, and I have done this for 30 years.
That’s why I react when fair weather pilots tell me I can’t do it. Or that the book says this or that.
This is the real world.

BTW, there is a differenece between BA Poor and BA Medium.

alf5071h

14th Dec 2018, 18:01

ManaAdaSystem

14th Dec 2018, 18:26

MAS, whilst public forums enable open opinion, these opinions are of little value without substanciating information or reasoned argument.

One aspect we have yet to discover is the standard of the landing performance charts the accident crew might have used; similarly for your views, especially over the years where there could have been different data source and understandings.

Then there is the question of safety margin; stopping within the published distance does not provide an equivalent level of safety to that expected by regulation, or the passengers.

The real world is uncertain, where ill-judged, false beliefs, and the variability of one’s ‘infallible’ actions, will sooner or later result in a surprise.
The skills in flying are required to manage thoughts and actions so there are no big surprises.

Are my arguments unreasonable? I am landing on a runway where my data says I can land, and I add additional margins with my technique.
As for data sources, I have done paper tables through various other sources up to todays very easy to use computer calculations. From the outside I have been through various vehicles using various speeds to measure BA, up to todays way of inserting conditions into a computer that spit out a BA. That includes the FAA and UK method of saying nothing.
Experience is everything. That is why I do what I do, and I have never been close to running off the end.

Stone69

14th Dec 2018, 18:34

I'm long retired now, but my one and only flight into LGA was Nov 30,2001... flying a 767-300 for AC . It was a charter from YUL bringing a corporate group to a 9/11 ceremony of some sort.... as both myself and the F/O were on reserve we didn't have much choice and neither of us had been there before.... it was a Friday night and it was busy, but really the worst part of it all was taxiing to a parking spot in the boonies after the pax had deplaned.... managed to avoid hitting anything, but it was real tight....

Reluctant Bus Driver

14th Dec 2018, 19:53

CurtainTwitcher

14th Dec 2018, 20:34

I'm surprised this hasn't yet been mentioned in the thread when it comes to the "legal" assessment of landing distance: SAFO 15009, Turbojet Braking Performance on Wet Runways (https://www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/safo/all_safos/media/2015/SAFO15009.pdf) because the FAA now says that the perhaps you won't stop within the factored landing distance.

Subject: Turbojet Braking Performance on Wet Runways
Purpose: This SAFO warns airplane operators and pilots that the advisory data for wet runway landings may not provide a safe stopping margin under all conditions.

Personally, 10 tail on a short wet runway on the performance limit with SAFO 15009 in the back of my mind, I would have gone elsewhere.

hans brinker

14th Dec 2018, 20:35

Are my arguments unreasonable? I am landing on a runway where my data says I can land, and I add additional margins with my technique.
As for data sources, I have done paper tables through various other sources up to todays very easy to use computer calculations. From the outside I have been through various vehicles using various speeds to measure BA, up to todays way of inserting conditions into a computer that spit out a BA. That includes the FAA and UK method of saying nothing.
Experience is everything. That is why I do what I do, and I have never been close to running off the end.

I have read a lot of your posts here, and they are always well grounded and reasonable. I do have to disagree with this one. If you as you stated in your previous post always land with 4 reds, you are doing something wrong. This isn't a technique issue. Unless there is a reason to have more than 2 reds like GS and visual GP indication not coincident, you should not dip below the path to increase you LDA on a normal landing. It might give you a more runway in front, but it will definitely decrease your safety margin for an early touchdown. On my plane if the radar altimeter crosses the threshold at 50ft, the landing gear crosses at 22', so dipping 20 feet low and I will hit the runway edge lights. Don't flare long or reduce power too late.

ManaAdaSystem

14th Dec 2018, 20:35

On the A319 the land app requires 6400 ft of runway with 10 knots tailwind and wet runway with 129000 lbs
landing weight. The 737-800 is a fast lander. I doubt very very much that their landing data showed a legal landing unless they were extremely light.Your hearing always improves at the hearing! A divert would have been quite rational me thinks. Live to fight another day..

This was a -700, and with 58.5 tons (he was probably lighter), landing is OK with 10 kts tailwind, FL30 on a wet 2000 m runway. Better margins with FL40.
The -700 is a lot easier to handle and stops much faster that the -800.
He was legal.

73qanda

14th Dec 2018, 20:37

I am landing on a runway where my data says I can land, and I add additional margins with my technique.
I can definitely see your logic but I don’t share your assessment of the risk. Why I don’t share it is probably a complex mix of life experiences, personal motivations, and expectation. Everyone will have a different combination of these so it is inevitable that where humans are involved there will be very different assessments of the risk of one particular activity whether that be a child climbing a jungle gym or a 737 Captain landing on a contaminated runway.
Some of my reasons for diverting in the circumstances that you have given are as follows,
1/ The braking action may or may not be as reported. There are many many cases of this reported globally on an annual basis and I have experienced it myself so I have an expectation that if I do this job long enough I will experience it again, when I do, I want more than 255m wiggle room (1700 x 0.15)
2/ The wind may not be as reported. I can mitigate this to a certain degree through knowledge of my expected ground speed approaching the threshold but I also know that if my brain is working hard on the required scanning both inside and outside of the aircraft my assessment of ground speed in the last 100ft might be left wanting.
3/ The machine itself is not infallible. Once I have selected reverse thrust all of my passengers lives will be relying on mechanical cylinders,hydraulic lines, speed brakes etc to operate as advertised. There is a very small chance that this might not happen. ( I acknowledge that this chance is very slim).
4/ I am not infallible. I have made mistakes in the past and I assume I will fly a less than perfect flare and thrust reduction in the future.
5/ The FAA SAFO issued in 2015 suggests that I should exercise conservative judgement of braking action even when the data suggests that I can legally land. This SAFO was motivated by incidents and accidents where braking action was less than anticipated.
These things combine to create a risk assessment in my mind that is more conservative and would result in a divert. That variation in decision making is to be expected. Let’s just hope it ends well for us all.

ManaAdaSystem

14th Dec 2018, 20:37

I have read a lot of your posts here, and they are always well grounded and reasonable. I do have to disagree with this one. If you as you stated in your previous post always land with 4 reds, you are doing something wrong. This isn't a technique issue. Unless there is a reason to have more than 2 reds like GS and visual GP indication not coincident, you should not dip below the path to increase you LDA on a normal landing. It might give you a more runway in front, but it will definitely decrease your safety margin for an early touchdown. On my plane if the radar altimeter crosses the threshold at 50ft, the landing gear crosses at 22', so dipping 20 feet low and I will hit the runway edge lights. Don't flare long or reduce power too late.

Thanks, but I go below the GS when it is needed. On nornal landings I just follow the GS or PAPI.

73qanda

14th Dec 2018, 20:47

I tell you, I see four red lights every time, and I have done this for 30 years.
I think the above statement may have been mis interpreted as meaning you always aim short of 1000ft.

ManaAdaSystem

14th Dec 2018, 21:25

Yes, I see that, but I said this with reference to the short and icy runway discussion.
Most of the time I’m not landing weight limited, so no need to go below the GS.

172_driver

14th Dec 2018, 21:57

On my plane if the radar altimeter crosses the threshold at 50ft, the landing gear crosses at 22', so dipping 20 feet low and I will hit the runway edge lights. Don't flare long or reduce power too late.

The 737 radio altimeter reads 0 at touch down - i.e. distance between my sole and ground. I would have thought the same applied over the approach lights with slight variance for different deck angles, perhaps?

73qanda

14th Dec 2018, 22:09

Only one foot variance.
Not sure what your ‘sole’ is but the gear is 15ft lower than your eyes when you are sitting in your seat with either flap 30 and 2.4 degree body angle or flap 40 and 1.4 degrees body angle.

172_driver

14th Dec 2018, 23:23

I meant bottom of my boots - i.e. my gear. When the "fifty" is called doesn't that mean my gear is 50 ft off the ground? Me sitting 15 ft higher is then 65ish ft up in the air.

I am not saying I have the answer - but I think the radio altimeter is calibrated to read distance between the wheels and the ground. Thus I am not going to drag my wheels through the approach light for being "a tad low on my RA",

PJ2

15th Dec 2018, 00:26

I meant bottom of my boots - i.e. my gear. When the "fifty" is called doesn't that mean my gear is 50 ft off the ground? Me sitting 15 ft higher is then 65ish ft up in the air.
I don't think so...

https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/448x600/2018_12_14_171858_b737_400_landinggeometry_l_e854aa4df8cd851 0ae2d42538b9a91133ecca2d2.jpg

Also, 737 radio altimeters do not usually read '0' on the ground. The readings I've seen (in data) are in the -4 to -2 range.

The radio altimeter antennae are located just behind the EE-bay access door. The #2 RA Transmitter is first, then the #2 RA receiver, then the #1's in the same order.

73qanda

15th Dec 2018, 00:29

When the "fifty" is called doesn't that mean my gear is 50 ft off the ground? Me sitting 15 ft higher is then 65ish ft up in the air.
On a standard ILS with a 50 ft TCH, the ILS antenna will cross the threshold at 50ft. The ILS antenna is about 3 feet in front of your chest and 15ft above the gear. The “fifty” call seems coincident with crossing the threshold in my experience.

Capn Bloggs

15th Dec 2018, 00:56

172's question was related to the rad alt call, not the ILS TCH. Why would the rad alt call "50" if the wheels were only 35ft off the ground? In my jet (not 737), when it calls "5", I'm still in the air...

PJ2

15th Dec 2018, 01:50

RA calls are generated by the GPWC and may be pin-selectable (on/off). So far, the AMM isn't clear on the how the call is generated.

73qanda

15th Dec 2018, 02:03

737er

15th Dec 2018, 02:32

Also, 737 radio altimeters do not usually read '0' on the ground. The readings I've seen (in data) are in the -4 to -2 range.

If you look, it’s always at 0 at wheel touch. The -2 is after strut compression.

hans brinker

15th Dec 2018, 02:41

Fair point.
I guess my question would be “ Does the rad alt call “fifty” when the rad alt is 50ft above ground? or does that rad alt call “ fifty”when the gear is 50ft above the ground?. I don’t think it calls it when the gear is at 50ft because it so often appears to call it exactly when we cross the threshold.

50ft call is at 50ft Rad Alt. Based on the antenna position and body angle the gear will often be lower, as you can see from the picture in the previous post. In my airplane around 25ft lower.

hans brinker

15th Dec 2018, 02:43

Thanks, but I go below the GS when it is needed. On nornal landings I just follow the GS or PAPI.

Sorry, but it should never be needed. Either you have enough LDA to land in the touchdown zone, or you go somewhere else. Just because you haven't hit the runway lights doesn't make it ok.

Reluctant Bus Driver

15th Dec 2018, 03:07

Anyone have access to 737-700 landing data? It would be interesting to see what the margins where. Even if legal it had to be pretty tight..

Reluctant Bus Driver

15th Dec 2018, 03:17

As some have alluded to, the usable landing distance, assuming they did not go below GS, is 4575ft. Not much to hang your hat on..

ManaAdaSystem

15th Dec 2018, 14:17

Sorry, but it should never be needed. Either you have enough LDA to land in the touchdown zone, or you go somewhere else. Just because you haven't hit the runway lights doesn't make it ok.

On paper I agree with you 100%. In real life I am very aware that braking action during winter operations is not an exact science. So, I add 100 - 200 m to the 12 m margin my calculations give me. I can pretty much guarantee that if you spent a few days in my cockpit to see what we do in the winter season on short, contaminated runways situated near high terrain, with moderate turbulence, snow showers, wind and 4 degree glide slopes... you would do the same.

ManaAdaSystem

15th Dec 2018, 14:57

Anyone have access to 737-700 landing data? It would be interesting to see what the margins where. Even if legal it had to be pretty tight..

On a 5800 ft (1768 m) wet runway with 10 kts tailwind, 56 tons, my tool says he would need max autobrakes.
FL30 1409 m actual landing distance.
FL40 1380 m actual landing distance.

Sailvi767

15th Dec 2018, 15:18

On a 5800 ft (1768 m) wet runway with 10 kts tailwind, 56 tons, my tool says he would need max autobrakes.
FL30 1409 m actual landing distance.
FL40 1380 m actual landing distance.

Were those numbers using fair braking action to account for the heavy rain?

ManaAdaSystem

15th Dec 2018, 20:55

Were those numbers using fair braking action to account for the heavy rain?

There are no options for «heavy rain» in my performance tool, and my calculations are based on our aircraft options. Which may or may not be the same as the SWA aircraft. I believe BA Good is used for a wet runway, however I have never had any braking problems on a wet and grooved runway.
India + Wet + Monsoon + Rain = a different story.

172_driver

15th Dec 2018, 20:57

50ft call is at 50ft Rad Alt. Based on the antenna position and body angle the gear will often be lower, as you can see from the picture in the previous post. In my airplane around 25ft lower.

If the 50-call occurs at the exact moment the antenna is 50 ft off the ground, the lowest point of the landing gear would be at 25 feet. Yet touch down occurs as the radio altimeter reads 0. Something doesn't add up in my head......

Reluctant Bus Driver

16th Dec 2018, 02:52

On a 5800 ft (1768 m) wet runway with 10 kts tailwind, 56 tons, my tool says he would need max autobrakes.
FL30 1409 m actual landing distance.
FL40 1380 m actual landing distance.

Usable glide slope landing length, assuming they did not go below, is 4575ft. Flap 40 actual landing distance is 1380m=4527ft. A legal margin of 48 ft? I am not trying to split hairs here, I am simply saying that looking at total runway length and equating it to legal landing distance is not correct. You have to look at available runway distance. It's an easy mistake. I know because I have made the same mistake, just not with consequences! On a razor thin margin like what happened in BUR it could be the difference between taxiing to the gate or ending up in the EMAS..

CurtainTwitcher

16th Dec 2018, 04:34

SAFO 15009 (https://www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/safo/all_safos/media/2015/SAFO15009.pdf)
Discussion: The root cause of the wet runway stopping performance shortfall is not fully understood at this time; however issues that appear to be contributors are runway conditions such as texture (polished or rubber contaminated surfaces), drainage, puddling in wheel tracks and active precipitation. Analysis of this data indicates that 30 to 40 percent of additional stopping distance may be required in certain cases where the runway is very wet, but not flooded.

If you are down to your last 48m to be "legal", then should you be doing this? I've diverted in similar circumstances from almost exactly the same runway length in due to heavy rain.

alf5071h

16th Dec 2018, 09:15

#159, without details of performance ‘tools’:- what is the basis of calculation, origin, who published them and the guidance for use, suggests weak knowledge ‘in the workshop’.
Blunt or rusty ‘tools’ are of little value; a key point about landing distances is that they are approximate (never really sharp), and that accuracy decreases with increasing ‘wetness’ and contamination.

Technical variation can be estimated, but the human contribution less so, especially in new or novel conditions. The conditions in each landing differ, we never experience the same landing twice; past comparison is of lesser value, but the lessons learnt should be, providing they are applied to the next landing.
Tools are best used by skilled craftsmen, according to circumstance, judgement - ‘the right way to cut the grain’.

BA ‘good’, is good relative to a wet runway. Wet performance is a projection, an estimate based on dry runways, which have a different version of ‘good’.
Consider how performance tables might accommodate the range of water depths up to 2.99 mm, but differ where 3 mm is defined as flooded (% of runway covered). The tables do not cover every combination, particularly when we consider runway surface texture, tyre wear; that’s why we have regulatory advice and the need for professional knowledge, and above all else the ability to apply professional judgement.

CT, I support your underlying view, but please there is no ‘legal’ value in performance, nor perhaps in anything we do in aviation. ;)

There are required or recommended values, and most important, justifiable choices of action - these are the basis of your defence.
There is nothing legal about sitting in EMAS quoting book figures when the lawyers are speeding down the runway behind you, measuring the actual landing conditions (‘legal’ hindsight), and forming their judgement on how you handled the situation and aircraft.

ManaAdaSystem

16th Dec 2018, 09:29

Reluctant Bus Driver

Thank you for your info. I just googled the available landing distance since I don’t fly there. With the numbers you came up with, a legal landing is not possible with our -700s. I don’t know the technical details of SWA aircraft, and the landing weight was a guess.
My numbers are raw numbers and do not include the legal margins. Add those on your runway lenght and this landing is a no go.

wiedehopf

16th Dec 2018, 10:58

ManaAdaSystem

I'm curious, does this actual landing distance include distance to the touchdown point?

Which margin do you normally have to add in your operation?
(Just being curious here so the numbers have some more meaning for me)

ManaAdaSystem

16th Dec 2018, 11:25

Yes, they include air distance to full stop.
As for the additional margins, some performance buff will probably come along with the explanation, but if i remember correctly, wet runway add 15% to the required dry landing distance. If you operate in Germany, you follow the same rules as me.
I just can’t be bothered to dig into the books at the moment.

Reluctant Bus Driver

16th Dec 2018, 15:33

Regardless of the theories posted here, I hope for the sake of the SWA crew, that their landing data was calculated correctly and that they touched down in the touchdown zone. If they did not do the data or ignored it they will be in a lot of trouble. It's a similar scenario to the AA 737 that went off the runway in kingston where there was no EMAS and the aircraft was destroyed. The crew is back on the line and had no enforcement action against hem because the NTSB and subsequently the FAA stated they acted in accordance with all procedures and did not know of the standing water on the runway. I hope this will be the case here as well..

PEI_3721

16th Dec 2018, 16:18

RBD
Agree re performance data. Is the 737 landing performance now based on OLD / FOLD calculations opposed to the old style ‘actual’ data. The wording in some posts suggest the latter, if so then either Boeing - tardy publication revision, or Operator - not using the best available data, might get a hard time from the FAA.

Re standing water; there are subtle differences between not knowing due to inaccurate surface descriptions, or if reported not ‘knowing’ because the previous information was not checked, based on what could be deduced - WXR etc, also not knowing or not seeking the best data at all. The dividing line of professionalism.

Where crews have followed procedures, this should not be taken to imply that the procedures are sufficiently accurate or have considered a wide range of situations.

CS 25.1591(~page 199) and particularly CS AMC 25.1591 (~page 878) give salutary enlightenment of the limitations in calculated performance.
Of note, these sections do not appear in the corresponding FAA documentation - non harmonised rule making.

FlightDetent

16th Dec 2018, 19:59

@ hans, 172 (and C/A)
Both 737 and 320 have quite a similar landing geometry. If the antenna passes THR on the G/S at 50', later the MLG will cross at 33' (34) which should be the RA indication (calibrated that way).

The radio call "over the numbers" should be 30 (not 50 btw) - the normal landing technique for the expected touchdown point at 455 m (1490 ft). Irrespective of LDA. Runways >= 2400m are a small cognitive challenge due to the placement of the large distance marker and PAPI (nicely documented by the incumbent's almost contradicting statements above).

The no-flare point is 200m (-ish) plus another 255 m (835 ft) is calculated for the flare. That's a fair deal. On a good day, a 400 m touchdown is perfectly possible while keeping the normal profile. 350 surely too with a thump :) Re-iterated: To fit the actual trajectory inside the calculation model, no extra skill or fjord-pilot tricks are required.

video: https://www.youtube.com/watch?v=j2WHVjP60Gg&feature=youtu.be&t=330 (https://www.youtube.com/watch?v=j2WHVjP60Gg&feature=youtu.be&t=330)
54' TCH/RDH, aim-point 314 m deep (nominal 3°)
35' RA when wheels over the THR
4 reds on the PAPI (displaced 470 m) at the round out and touchdown exactly abeam https://www.google.com/maps/@48.9931357,2.5714839,266m/data=!3m1!1e3

However, the plot thickens in the second act where the relationship between the actual achieved vs. calculated deceleration needs to be discussed.

ManaAdaSystem:I'll pass on the measuring exercise, yet for my improvement: Which of these I actually said do you disagree with?

Shorter runways require correct flying, whereas the long runways don't, absolutely.
anything beyond 600 m is not correctly done. Irrespective of runway length.
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.
The touchdown is usually decided between 150 and 50 feet above the ground
350 (m touchdown) ...with a thump ...is surely ...perfectly possible ... while keeping the normal profile
To fit the actual trajectory inside the calculation model, no extra skill or fjord-pilot tricks are required.
Aiming closer to the threshold, steepening the angle in the last stages is more consistent with the intention (of saving distance)
I am sure everyone does a bit more pushing on the short runways and tries to tweak it closer to the tarmac edge.
A cautious duck under… is part of the duty even, to make sure all the odds are in our favour. The (another) extra 90 meters is not a negligible distance.
The touch-down point and speed are what matters.
retard the thrust to idle by 15'
Vref to Vref -5
"no landings beyond TDZ markings" is a sound principle
the last two (extra and incorrect) distance markers on the pavement (at BUR RWY 8) are nothing but a deathtrap.
(after the touchdown) the plot thickens ... where the relationship between the actual achieved vs. calculated deceleration needs to be discussed
(due to low friction) The last 60 m (at the far end) you might critically need, and as if they did not exist (when wet or worse)

The numbers are not priorities, just labels so you can respond easily.

73qanda

16th Dec 2018, 20:04

One thing comes to my mind regarding this conversation.
Why is the First Officer not the Captain? If decisions around takeoff and landing performance ( along with hundreds of others) were simply a matter of checking the data and seeing whether it said yes or no, then plenty of 19 year old bright young things would be employed to operate the airliners flying around the globe.
The reality is that the regulator and the company have determined that the aviation environment has too many variables for this to work. For safe operation there needs to be an experienced person in the flight deck with the authority to say yes or no regardless of what the computer says. To abdicate decision making to the onboard performance tool is to disregard that reality and the paying passengers and their relatives would rightly feel uncomfortable if they were aware of this happening.
As technology becomes faster, more accurate and more reliable, are we less inclined ( as Captains) to exercise our command authority based on experience? I think so. There are examples of it on this thread.
If we are less inclined now than thirty years ago, where does that leave us twenty years from now? There will be Captains who have witnessed extremely reliable technology their entire lives, there is every chance of increasing reluctance to over ride or even question it’s solutions.
I think we need to be aware of this tendency within ourselves and actively question the common sense element of our decision making and consider what the passengers, company, and regulators expect of us.

Gipsy Queen

16th Dec 2018, 20:33

One of the most pertinent contributions to Prune I have read in quite some time. It does touch on some pretty profound philosophical considerations.

Junkflyer

17th Dec 2018, 04:59

Have not every post on this long thread.
My thoughts (and actions in the cockpit) is that a short runway,
tailwind, or wet runway require vigilance. Having two of these together requires an extra amount of vigilance and thoughts of holding or diverting,
All three, is realistically something you don't want to subject yourself, crew and pax to. A 5800 foot runway with numbers that give just a margin of just a couple of hundred meters is unacceptable.
Heavy rain may mean that the braking action and reported winds are incorrect.
Don't know all the facts in this case, but everything reported does not seem to point to landing in these conditions.

Sailvi767

17th Dec 2018, 11:44

ManaAdaSystem

BUR RW 8 is 5802’ long not 6500’. Using medium or a 3 for braking action that +R would require I can’t make the numbers work for a 700 with a 10 knot tailwind.

Reluctant Bus Driver

17th Dec 2018, 15:57

As some have alluded to, the usable landing distance, assuming they did not go below GS, is 4575ft. Not much to hang your hat on..
I realized afterwords that this statement is incorrect. You use the runway distance on the 10-9 pages minus any displaced thresh hold. In this case it is indeed 5802 ft., so they may very well have been legal with a very light -700. Apologies.

737er

17th Dec 2018, 19:15

Sailvi767

Is 3 automatically required for heavy rain? Does that override the airport’s current field condition report?

Sig229

19th Dec 2018, 02:16

Not at SWA anyway. Heavy rain is a weather condition, not a runway condition. You could always argue to use a more conservative setting than is being reported, but you'd still just be guessing. There's a table in the back of our AOM that provides a relationship of runway conditions to RCC values. Wet is damp or standing water up to 1/8in, RCC 5. There's also a slippery when wet for excess rubber, RCC 3, which is probably what they actually had and if it was reported would most likely have prevented them from attempting to land. But when you're given an RCC of 5 and "braking action good" by the Tower it's hard to argue with their decision based on what they knew at the time.

Sailvi767

19th Dec 2018, 11:43

The report of the rain increasing to +R should cue any crew to downgrade to medium braking for calculations.

PEI_3721

19th Dec 2018, 13:10

Sig, interesting views.

Because ‘slippery when wet’ is additive, not directly related to weather or runway contaminants, it might be better used to reduce the assessed braking action; select the next lower value.

‘Tower’ information is advisory; it might be the best assessed or calculated, or their best guess by looking out of the window, worst still, incorrectly passing on a PIREP.
None of these remove the need for reassessment according to the situational conditions.

Some operators have a rule of thumb which linked any red WXR over the airfield in the preceding 15 min, to the assumption of a flooded runway.

Risk is not determined by assessing what is known, it’s the understanding of what is not known and possible consequences of the knowledge gap.

ImbracableCrunk

22nd Dec 2018, 17:37

At my operator, +RN equals a Runway Condition Code of 2. That would limit the tailwind to 5 knots. However, the braking action report of GOOD from the preceding aircraft could have upgraded the BA to GOOD and possibly allowed the landing, depending on weight.

aterpster

23rd Dec 2018, 14:29

Unfortunately, we'll never know.

Blade Master

24th Dec 2018, 05:52

One of the first posts in this thread quotes aviation-safety.net's web page that claims "Aircraft damage: Minor". It looks like the cowlings are resting on the ground, although aerial views online do not clearly show scrap marks on the EMAS blocks, with blocks costing around $2000 each average, not including labor. Is there anyway this accident is minor, or does a minor accident go up to a few million dollars in repair costs?

westhawk

24th Dec 2018, 06:11

I bolded the most relevant parts pertaining to NTSB 830 reporting requirements. Major repairs are defined in CFR 14 part 43 and require a properly filled out and signed form 337. The completion of this form constitutes the approval of the repair by an appropriately qualified and authorized inspector and becomes part of the aircraft maintenance record.

[edited for brevity]

Aircraft accident means an occurrence associated with the operation of an aircraft which takes place between the time any person boards the aircraft with the intention of flight and all such persons have disembarked, and in which any person suffers death or serious injury, or in which the aircraft receives substantial damage. For purposes of this part, the definition of “aircraft accident” includes “unmanned aircraft accident,” as defined herein.

Substantial damage means damage or failure which adversely affects the structural strength, performance, or flight characteristics of the aircraft, and which would normally require major repair or replacement of the affected component. Engine failure or damage limited to an engine if only one engine fails or is damaged, bent fairings or cowling, dented skin, small punctured holes in the skin or fabric, ground damage to rotor or propeller blades, and damage to landing gear, wheels, tires, flaps, engine accessories, brakes, or wingtips are not considered “substantial damage” for the purpose of this part. Substantial damage means damage or failure which adversely affects the structural strength, performance, or flight characteristics of the aircraft, and which would normally require major repair or replacement of the affected component. Engine failure or damage limited to an engine if only one engine fails or is damaged, bent fairings or cowling, dented skin, small punctured holes in the skin or fabric, ground damage to rotor or propeller blades, and damage to landing gear, wheels, tires, flaps, engine accessories, brakes, or wingtips are not considered “substantial damage” for the purpose of this part.

strawpile

5th Sep 2019, 03:42

edmundronald

That is a comforting sentiment to entertain, but in the real world, a pilot who diverts to an alternate in order to avoid a landing that the data supports will most certainly get a phone call from his base chief pilot asking him to explain himself. This implicit pressure certainly can cloud judgement. Unfortunately, the aviation industry employs "binary decision making" (i.e. there is no spectrum of safety, an operation is either safe or unsafe, no grey areas are acknowledged).

neilki

5th Sep 2019, 12:45

My operator uses LD*SAFO +500'. I'm very happy to report that we're unlikely to get a phone call for making a prudent decision in marginal Wx.
Either the environmentals were incorrectly reported in this case, or the jet didn't land in the right place. I know Burbank is closer to many peoples destination than LAX, but this was taking things a little too far...
As an aside, I watched Mike Pences' 737 steer round the EMAS in LGA one rainy night. Luckily the six lane Grand Central Parkway was there to absorb his overrun...Some wit photoshopped the Vice Presidential Seal on a satellite picture of the EMAS....

aterpster

5th Sep 2019, 13:59

Perhaps at SWA, but not at most airlines on that runway with the weather at the time.

Airbubba

11th Feb 2021, 19:55

NTSB Accident Docket opened: NTSB Docket - Docket Management System (https://data.ntsb.gov/Docket?ProjectID=98737)

FlightDetent

11th Feb 2021, 22:26

Tower reported wind with the landing clearance directly from the tail, 9 kts, advisory call later with 10 kt tailwind, duly noted as a maximum by the pilots on the CVR.
Approx. 750 RA crew verbalizes 20 knots tailwind from the FMC, but then mere 4 seconds later the tower advises 270/11.
(*)
No further wind observations recorded on the tape.
GS faster than IAS at touchdown by 23 knots, ouch.
Touchdown at Vref 126, around 2500 ft beyond the threshold.
Deceleration diminished to half the previously recorded rate for the last 5 seconds before entering the EMAS.

(*) in detail here what followed: 0901:36.2 BUR wind two seven zero at one one.
0901:41.3 HOT-2 #.
0901:43.2 HOT-2 er there's five hundred.
0901:44.8 HOT-1 roger.
0901:48.9 HOT-1 we need some kind of lights. I got some lights.
0901:51.6 HOT-2 alright we got eleven knots. you want to call it good?
0901:54.5 HOT-1 yeah.

This, even from a cushy chair, is still somewhat an eye-watering read. If CRM classes on confirmation bias had an exercise for the students to write a script from a hypothetical accident, this would be exactly it. Check the timings, one can almost hear the skipper's brain working the human error. Then the sentence in brown just sealed it airtight, for the grace of God.

Airbubba

12th Feb 2021, 02:51

Im just trying to keep it real here regarding the specific issue of did they think they had an 11 knot tailwind component and just landed anyway. To that I’d say it’s monumentally and fantastically implausible.

It looks like they acknowledged the 11 knot tailwind and indeed landed anyway.

The Aircraft Performance Study in the Accident Docket has this analysis:

Reported vs. actual wind conditions

The maximum tailwind allowed by the SWA AOM is 10 kt. The tailwind component corresponding to the wind report provided by the ATC tower at 09:02 (wind from 270° (magnetic) at 11 knots) is 10.8 kt., i.e., higher than the limit. However, the Captain stated in his interview that he and the First Officer “acknowledged this call and agreed that the tailwind component was 9-10 kt. and it was within limits.” The error in the crew’s estimate of the tailwind component is admittedly small (about 1 kt.); consequently, it is possible that if the winds reported by the tower had been more consistent with the winds recorded by the ASOS (and computed using the FDR data), which were 3 to 5 kt. higher than those reported by the tower, the crew might have recognized that the AOM tailwind limit was exceeded and abandoned the approach.

And, it wasn't just the one knot over the AOM tailwind limit that caused the plane to overrun the runway according to the Aircraft Performance Study:

The higher than expected tailwind, the longer than normal touchdown point, and to a lesser degree, the faster than nominal approach speed all contributed to the overrun. However, of the three, the long touchdown is the most significant contributor. The airplane could have stopped on the runway with the high approach speed and tailwind even if the touchdown had been 312 ft. longer than the nominal 1,500 ft. from the threshold; however, with the actual touchdown point of 2,504 ft. from the threshold, either the tailwind or faster approach speed by themselves would have prevented a stop on the runway. Per the SWA AOM, once the airplane overflew the nominal 1,500 ft. touchdown point, the PWB landing distance calculations became “invalid” and “a go-around [was] the better option.”

They did discuss the threats in the briefing.

0824:52.9 HOT-2 yeah it's wet with a tailwind...and # short runway.

0824:58.3 HOT-1 awesome.

0825:00.0 HOT-2 yeah that's great. what could possibly go wrong.

rnzoli

14th Feb 2021, 08:38

They did discuss the threats in the briefing.
Now I really start wondering how the "awesome" word was pronounced.
I tend to imagine it with a sarcastic touch, but what if the pilot behind HOT-1 was actually excited about this challlenge?
The pilot behind HOT-2 was far more afraid, yet didn't speak up for busting the OM limit and calling for a go-around.

FlightDetent

14th Feb 2021, 10:17

Contrary opinion here. The HOT2's indistinctive relay of information and downplaying tone greased the stairs.

Clear, unbiased and precise delivery of support facts is the true responsibility of the PM and that has completely failed here. Although we do not see the whole story, why he communicated in such an inadequate manner.

Tangent question: If there was a SIM scenario where tailwind would gradually increase from 7 to 20 knots (assuming limit at 10) below say 400 feet once visual after breaking the cloud, and the PM failed to speak up that the landing must be discontinued,... is it a fail-and-retake situation where you work? Probably it should be, it is a two-pilot operation after all, yet my bet is there is no such general training practice. Certainly have not experienced one like that.

Regardless of the above, the crew was illegal to start lt the approach with regards to LDA under the reported wind conditions. No lessons learned from the previous overrun. The only topic left to discuss is if they did, what will prevent me doing the same as well.

1) Clarify to oneself the difference between the so-called and useless touchdown zone definition (shortest of 900 m or 1/3 runway) and the acceptable touchdown point from the stopping performance viewpoint: THR plus 400 m +/- 200 or 1200 ft +/- 600.

Going beyond the target of 1500 ft / 500 m starts to remove the first protective coat and losing three of them will put the naked truth on the front page. So, train your mind thoroughly to execute a G/A when landing deep. Let there be no doubt the subconscious WILL play your rational self very dirty, same as it did to the skipper here. There will be zero defences not do the stupid thing. Raw sensory information that will trigger an automated escape drill is the
only hope for cases where the PM is gone missing. If you happened to step over any lines in the previous moments no matter how thin and formal, do not expect the F/O to speak as the plot thickens. It's the human nature to stay put and be a good boiled frog.

In pilot speak: No landings beyond the last distance markings! Be acutely aware that PAPIs must be disregarded as a general rule because many of them mark for an aiming point that is already on the far edge of where the touchdown is permissible.

2)... passing on to the next contributor..