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738 over runs


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You land a plane 6500’ down a wet 10,000’ runway and expect..... what? Left the runway end at 65kts groundspeed. Overran the runway by 550’.

Forget that it was a 737NG which has its own unique landing distance issues. Based on the Avherald flight data this was an example of appallingly poor airmanship and decision making. Stable approach criteria........ apparently just a concept.

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The only thing I can think of , as to why they took a huge tailwind , would be to avoid thunderstorms on the approach to  the into wind side of runway.

Never take a tailwind, on a wet runway, with 737-800!!! Go somewhere else or hold till storm goes by.

 

 

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From the initial report:

Quote

According to Mode-S data transmitted by the aircraft the aircraft landed long and hot, 1500 meters before the runway threshold the aircraft was descending through 950 feet MSL (corrected for local pressure, actual Mode-S reading 1500 feet)/661 feet AGL at 194 knots over ground, touched down about abeam taxiways T/F (about 1950 meters/6400 feet past the threshold, about 1000 meters/3300 feet before the runway end) at about 130 knots over ground, overran the end of the runway at about 63 knots over ground 

No surprise here there was an accident!!

What are guys thinking?!?!   With the number of overruns and incidents, most recently with WJ in HZ,  will this become the new norm?

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On 1/18/2020 at 8:33 PM, Marshall said:

From the various reports on PPrune, AVHERALD ETC, there are numerous reports of 738 over runs, excursions etc. What is wrong?    

maybethedriversnot theaircraft.

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2 hours ago, Marshall said:

or is the aircraft just too aerodynamic (floats more)? 

Hi Marshall;

In general. Not commenting on this latest accident...

As you might expect, I'm reluctant to accept that an airplane is "too aerodynamic and so floats more" as a reason for long landings and potential overruns. I think that the touchdown point is, with the rarest of exceptions, well within the pilots' ability to control, and if the airplane is floating along just above the runway, almost invariably the pilot is permitting it to do so.

Let me push this just a bit if I may as I wish to avoid handing over to the airplane, what may be human factors, decision-making and skill levels in overrun accidents. If I recall, most overrun accidents occured after touching down in the last half of the runway?...I'd have to look, of course.

I think that, once the planning work has been done and the decision has been made to begin the approach, the touchdown point in all but the rarest of circumstances is well within the crews' ability to control when the airplane touches down. Of course, this assumes a stabilized approach from 1000ft AGL.

Put another way, whether Boeing or Airbus, I think that in a majority of landing circumstances it is a choice to allow the aircraft to float along just above the runway surface waiting longer than 8" for the airplane to settle and land.

I think the techniques provided in both the FCTM and the FCOM for the 50ft-to-touchdown segment provide ample guidance for getting the airplane onto the runway within the first 2000ft.* By this I mean, if one flares a bit high and begins to ride on ground effect, one can put the aircraft onto the runway with suitable control input. "Rolling it on" (slight forward check on the CC), was almost standard on the DC8 & DC9. The only aircraft one never pushed the CC forward just a little was the L1011 as the MDLC raised the spoilers to increase the descent rate!

Most of the time our runways are suitable and sufficiently long to permit some 'finesse' in the touchdown without compromise. But in my opinion I think one should fly the aircraft onto the runway to the touchdown point one has mentally selected on the approach.

I don't think smaller wheels/brakes, too-aerodynamic an airplane, the requirement for (slightly) higher approach speeds for the 800 are primary or combined contributions to overrun accidents. The Actual Performance FCOM Chapter provides data for crews to plan the landing on a less-than-ideal runway in less than ideal weather conditions.

*B737 NG FCTM, "Landing", p6.8, June 30 2019

Edited by Don Hudson
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Avherald says ADSB data had the aircraft 800’ AGL at 1 mile back from threshold (950’ MSL with airport elevation 163’).

Using the 1:3 rule that is way too high for a 3 degree FPA. As a result, the aircraft is alleged to have touched down nearly 5000’ beyond the touchdown point.

That is not floating. That is continuing an unstable approach to touchdown.

There is airport video of the aircraft running off the end of the runway then disappearing over the embankment.

Pegasus has 3 B737-800 runway overruns in the last 25 months. 

Edited by rudder
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hi rudder;

Yes, clearly this approach, this accident is shaping up to be, by a very long way, an outlier so far away from SOPs that the books are meaningless. Reminds me of the American Airlines 738 accident at Kingston. I wonder what the pressures were to cause such decision-making?

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John Wayne-Orange County, Santa Ana California. The runway is 5701 feet, grooved. Monsoonal rain, 737-700 we need good braking with flap 40 and autobrake max or we divert. American Airlines lands their 737-800 in front and reports good braking. We would have been stopped in 4000 if the auto brake was left on.

I can't say that the 800 has the best braking for a narrow body with a max landing weight of 146,300 lbs. I also cannot figure out why NG pilots continue to accept long landings and tailwinds. Our company limit is 10 knots, I don't even like to entertain that.

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3 hours ago, Don Hudson said:

hi rudder;

.......................................I wonder what the pressures were to cause such decision-making?

Don,

There are times when there is no "pressure", just a very bad decision by the driver, based on his own 'presumed' ability  that he can handle the situation.

 Some  may call it fear of being looked upon in unfavorable light, (can't get the job done), if "he/she" calls for a "go-around". Others may call it an "ego override" in that the driver feels he can master any situation....

When it is all said and done, the brotherhood of pilots don't want to say it out loud but in these cases most think it to themselves.........Pilot Error.

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Kip,

Bad decisions and actions happen, but rarely in complete isolation. Considering a company's culture, training/checking regime and even hiring practises is not exonerating individuals where investigations make clear how an accident occurred. But unless the context is considered, the same accidents seem to re-occur.

Question for any and all here: I understand any answer depends upon conditions but what would you consider a "long landing", and what would you consider acceptable?

Edited by Don Hudson
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Yes, late night, not well-worded ? Also, when composing the post I somehow lost the quote from Leeroy's post in which the question was posed:

10 hours ago, Leeroy said:

I also cannot figure out why NG pilots continue to accept long landings and tailwinds.

So yes, the question I'm asking is the one you've posted above.

Obviously there will be a range of values and flare durations. What is 'normal' and acceptable, what draws one's attention with eyebrows raised and what raises the hair on the back of one's neck? I know it depends upon weather & runway conditions.

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Don,

As you stated the answer depends on conditions, primarily the runway condition. In fact "conditons " can be very encompassing  and I don't think anyone can give you an absolute answer unless a full range of conditions are given and that  may include, aircraft type, weather, day/night, fuel remaining, aircraft weight, pilot experience and even the pilot's state of mind..

I have certainly "gone around", particularly in the C130 while operating up North and there were a few cases where I had to tell the PF to "Go Around" because, based on his/her performance the landing was going to be  beyond what I deemed acceptable .........in other words...not enough runway..

To be honest I have never been in the pointy end where a completed landing raised the hair on the back of my neck. In WD, CP, and AC there was never a point where i was concerned about the PF flying and obviously we always aimed at 1000 feet on the rw with  TD at or near 500-800 feet.

I had one go-around  at YYR with a B737 because once we had the runway visual after a minimums ADF approach, I felt we were in no position to get accurately lined up and make the runway unless we landed about 3000 feet down the runway.

Interestingly enough I made a very long landing with the CV580 on a small strip in Europe but I deemed it was possible because I knew the aircraft and I had the experience on type. The runway was about 6500 feet long but unfortunately the first 1500-2000 feet was occupied by wandering goats, (uncontrolled airport), but I knew, given all the other conditions that I only needed about 4000 feet to land and stop,( in Mil terms the procedure  is called MAX EFFORT landing). If you have not flown the CV580 then you would be surprised how those 8 prop blades become giant speed brakes when the thrust levers are pulled to flight idle, and naturally we had full reverse.

So to drift off a bit on a tangent.......are the long landings / over runs being done by inexperienced pilots, low time on type  pilots or "pressured" pilots or just pilots who feel they can cut it, (ego driven), no matter  what conditions confront them ??

In my world, with jet aircraft,  there is absolutely no reason to land long ....but it will happen again, I guarantee that.

 

Edited by Kip Powick
speling
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Thanks Kip, a good read. I've not flown anything with two 16ft "speedbrakes" but I'll bet they test the shoulder harnesses. 

From one comment, (unless we landed about 3000ft down the runway), would it be fair to say that three-thousand feet from the threshold is probably not what to aim for, no matter what conditions?

An airborne distance from the threshold to touchdown of three thousand feet appears to be the upper limit in most of the documents which govern(ed) us, (FCTMs, FCOMs), and two-thousand feet from the threshold seems the upper end of the touchdown zone according to Boeing, (B737 NG FCTM, "Landing" chapter, p.6.8.), with a flare duration of 4" to 8".

I wish I knew the psychology and perhaps the physiology behind long landings but I don't, and so can't make any assumptions or conclusions although I think most here could hazard a good SCWAG. One factor can be ego but in discusions I find that that is less important now, (so they say...); I'm wondering more about experience and training.

Fortunately I suppose, the frequency of overruns vs. the tens of thousands of landings each day around the world doesn't provide a very good "dataset" to tell us anything solid. What that does tell us is the opposite - that the safety levels and standards and threat-management systems preventing untoward/expensive events which aviation has achieved is the envy of other industries.

As has been pointed out by several here, there is simply no good reason to "land long"; I've heard most of the reasons early in the career...,"stay above the wake turbulence from the previous heavy", "aim for this exit point or taxiway (to save time to the terminal)", "give the passengers a nice arrival" and so on and none of them are valid. There is simply no justification for a fifteen-second flare duration - anytime.

 

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2 minutes ago, Don Hudson said:

From one comment, (unless we landed about 3000ft down the runway), would it be fair to say that three-thousand feet from the threshold is probably not what to aim for, no matter what conditions?

Absolutely !! 

 Unless, of course you were landing at CFB Namao when they had a runway that was in excess of 13,500 feet !!!

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Thanks again Kip...that does help me sort out perceptions of what would be considered a "long landing". I suspect that would be most everyone's view on the matter.

I think that any airborne distance that exceeds 3000ft is in "no-man's territory" and, all being equal, is indefensible if something goes wrong. There is no "slop" built into the performance data and no documentation that I'm aware of that provides validation or support for any airborne distance beyond 3000ft or flare durations above eight seconds.

I emphasize for others reading this who sit in either front seat, that every touchdown point is, with very rare exceptions, within the PF's control because that's the way these aircraft are designed, tested and certified to be flown. Recent events have demonstrated that if the flare/touchdown is incorrectly planned and/or handled, one's airplane can overrun a 9000ft runway.

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Don,

I agree with the conversation you and Kip are having

I do think that the 800 gets a bit of a bad rap for braking. On speed and on the numbers it generally makes the numbers in the manual. I don't know if it's a mindset due to the automation, but I find some tend to go through the motions (SOP) when selecting auto brake, they see a number and take it as a given. In my book if I have selected auto brake 3 and I don't feel some braking it's time to get more aggressive, not when the planned exit is rapidly approaching.

I think the long landings, tailwinds and unstable approaches are cultural, company culture. When the NG first came into our fleet there were a lot of unstable approaches continued to landing. It was pounded into us to just go around. Can't say it doesn't still happen, but rare.

Long day of LGA turns in crappy weather, hope this is legible.

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