737 runway overruns
Join Date: Jun 2000
Location: last time I looked I was still here.
Posts: 4,507
Likes: 0
Received 0 Likes
on
0 Posts
Telling the PF to "put it down" (during a long hold-off) is asking for trouble. That can lead to "spiking" the aircraft nose-wheel first and a bounce is the likely result. It is usually a nervous captain saying "put it down" as I can not visualise a first officer demanding that if the captain is landing.
I found many pilots were not advised how to 'put it down'. If it became necessary it was often caused by too much back elevator; thus the answer was to relax the nose and land flat; or worse. The other danger is pulling back even more. My technique, if tending to float a couple of feet above the tarmac, was to 'drop a wing', remembering of course where the wind was. Immediately a main wheel touches down the speed brakes deploy and the a/c sits down.
It's a simple technique, it works, and is not emphasised; but I used to teach it.
I found many pilots were not advised how to 'put it down'. If it became necessary it was often caused by too much back elevator; thus the answer was to relax the nose and land flat; or worse. The other danger is pulling back even more. My technique, if tending to float a couple of feet above the tarmac, was to 'drop a wing', remembering of course where the wind was. Immediately a main wheel touches down the speed brakes deploy and the a/c sits down.
It's a simple technique, it works, and is not emphasised; but I used to teach it.
Join Date: Jul 2006
Location: Somewhere over the rainbow
Posts: 946
Likes: 0
Received 0 Likes
on
0 Posts
Hello RAT 5,
Very true. What you say works so nicely. Very helpfull especially with the ones equipped with Sharklets who are good gliders haha. One little push on the side and it goes down smoothly. Also learned that one from colleagues but not officially from instructors during initial training.
Very true. What you say works so nicely. Very helpfull especially with the ones equipped with Sharklets who are good gliders haha. One little push on the side and it goes down smoothly. Also learned that one from colleagues but not officially from instructors during initial training.
Join Date: Jun 2000
Location: last time I looked I was still here.
Posts: 4,507
Likes: 0
Received 0 Likes
on
0 Posts
Also learned that one from colleagues but not officially from instructors during initial training.
And I've always wondered why not. It works for most a/c. We're talking a couple of feet off the deck, not 6 feet. Boeing does write the x-wind limitation for side-slip only approach & touchdown due to trailing edge outboard flap grond contact. I wonder if they are too nervous to include our little 'piloting technique' as there will always be some who mis-interpret it and infringe that other limit. We're back in the circular discussion about training pilots not monkeys. All has to be for the lowest common denominator. It would be nice to raise the bar so the lowest was still a high standard. But that's for another day's debate over a cold one.
Still, for instructors to pass it on, like many other 'unofficial' tips & tricks, seems a proactive move to prevent some over runs, especially on the short runways B737's often operate into. Sitting there floating in ground effect hoping that the beast will settle in time, and wondering why you didn't use F40 in the first place, and wondering if there was a gem of an answer to help the dunlops meet the tarmac PDQ is not a cosy predicament, when there is a little gem.
And I've always wondered why not. It works for most a/c. We're talking a couple of feet off the deck, not 6 feet. Boeing does write the x-wind limitation for side-slip only approach & touchdown due to trailing edge outboard flap grond contact. I wonder if they are too nervous to include our little 'piloting technique' as there will always be some who mis-interpret it and infringe that other limit. We're back in the circular discussion about training pilots not monkeys. All has to be for the lowest common denominator. It would be nice to raise the bar so the lowest was still a high standard. But that's for another day's debate over a cold one.
Still, for instructors to pass it on, like many other 'unofficial' tips & tricks, seems a proactive move to prevent some over runs, especially on the short runways B737's often operate into. Sitting there floating in ground effect hoping that the beast will settle in time, and wondering why you didn't use F40 in the first place, and wondering if there was a gem of an answer to help the dunlops meet the tarmac PDQ is not a cosy predicament, when there is a little gem.
Join Date: Aug 2005
Location: fairly close to the colonial capitol
Age: 55
Posts: 1,693
Likes: 0
Received 0 Likes
on
0 Posts
737 generally doesn't like to be landed half down the contaminated runway, with speedbrakes not armed, selecting reverse 10 seconds after touchdown with VREF + a lot, using lower flap setting and one reverser inop.
Which is how most of those overrun reports go (regardless of aircraft type I might add).
Which is how most of those overrun reports go (regardless of aircraft type I might add).
Planting oneself halfway down a contaminated runway is usually cause enough - for any transport category aircraft.
[I] My technique, if tending to float a couple of feet above the tarmac, was to 'drop a wing', remembering of course where the wind was. Immediately a main wheel touches down the speed brakes deploy and the a/c sits down.
It's a simple technique, it works, and is not emphasised; but I used to teach it.
It's a simple technique, it works, and is not emphasised; but I used to teach it.
Join Date: Mar 2007
Location: Another Planet.
Posts: 559
Likes: 0
Received 0 Likes
on
0 Posts
What are the statistics for undershoots for similar types over the same sample period?
Once upon a time Bae146-300 series were landing at Berne, 1300m of runway and none of this 300m wasted real estate merde!
Then all runways were fitted with PAPIs for long-bodied aircraft and we were all forced to aim further down the concrete.
Then people like Mr Boeing insisted on factoring the approach speeds with half STEADY headwind component up to Vref+20kts even though windshear was not necessarily present.
Add to these the average performance of line dogs, some of whom should not have been in the front seats and hey presto we have numerous excursions onto the inhospitable terrain in the overrun area with inevitable hull losses and fatalities/injuries.
It's purely an energy management task corrupted by some rather odd presumptions about how the 'frame behaves in IAS and infection by the large eye-wheel brigade.
Why is the runway threshold marked by "piano keys" and are there any medium category jetjocks out there capable of dropping the 'frame onto the concrete just beyond said markings?
Awaiting the undershoot stats with my tin hat on................🙄
Once upon a time Bae146-300 series were landing at Berne, 1300m of runway and none of this 300m wasted real estate merde!
Then all runways were fitted with PAPIs for long-bodied aircraft and we were all forced to aim further down the concrete.
Then people like Mr Boeing insisted on factoring the approach speeds with half STEADY headwind component up to Vref+20kts even though windshear was not necessarily present.
Add to these the average performance of line dogs, some of whom should not have been in the front seats and hey presto we have numerous excursions onto the inhospitable terrain in the overrun area with inevitable hull losses and fatalities/injuries.
It's purely an energy management task corrupted by some rather odd presumptions about how the 'frame behaves in IAS and infection by the large eye-wheel brigade.
Why is the runway threshold marked by "piano keys" and are there any medium category jetjocks out there capable of dropping the 'frame onto the concrete just beyond said markings?
Awaiting the undershoot stats with my tin hat on................🙄
Join Date: Jun 2000
Location: last time I looked I was still here.
Posts: 4,507
Likes: 0
Received 0 Likes
on
0 Posts
Ah Ha. Now I remember why my PPL had a 'short field landing' included in the test. The last time, on a short runway, I retracted the flaps on my Boeing, before I had vacated the runway, my name was up before 'The Beak' ASAP. But sir, I cried................
my PPL had a 'short field landing' included in the test
Since most instructors who came back from the war became civilian flying school instructors because of lack of available jobs in the start-up airline industry, these instructors taught what they in turn were taught by military flying instructors. Usually the technique was to knock off 10-15 knots from the normal over-the-fence IAS and plonk it on the threshold and slam on the brakes and hey presto there was your short field landing.
Try knocking off 10 knots below Vref in the Boeing and Airbus and as you say it is tea and bikkies with the chief pilot.
Nowadays short field landings on singles and twins are still required to be demonstrated for the PPL and CPL as per CASA syllabus but speeds used are as per normal threshold speeds from the AFM or POH. Knock off 10 knots over the fence in the CASA test and you fail. Then join an airline and there is no such thing as a short field landing in an airliner - not legally, anyway.
There has been no attempt by CASA to delete the syllabus requirement for a demo of a short field landing for the PPL and CPL tests. It is long overdue. Caution
All the above is IMHO.
Join Date: Mar 2007
Location: Another Planet.
Posts: 559
Likes: 0
Received 0 Likes
on
0 Posts
Who mentioned short field landings?
C'mon folks, concentrate?
Read my original post and then work forwards from when jet transports were landed close to the threshold with minimal additions to Vref/Vapp until the current scene where 300 metres of paved runway real estate are wasted and for some odd reason a headwind is regarded as a special case requiring extra knots of IAS even though shear/turbulence is NOT a factor.
Probably I'm biased as my first post-military job was the Bae146 where the manual clearly stated "in order to make the scheduled landing distance...cross the landing threshold at Vref (airbrakes fully deployed) aiming to touchdown at Vref-7kts". Yes, that hyphen was a minus sign!
Whilst I appreciate the Boeings various may not use airbrakes whilst airborne, my abiding memory of transitioning onto the 74s and then 73s is that flying even at Vref over the landing threshold caused apoplexy amongst trainers and experienced capts, so that the only way to avoid criticism was to arrive at the threshold with minimum Vref+5kts and then everyone was happy.
Which has left me wondering why Boeing mentions Vref at all if it's never used. I suspect a ruse to get the paper Vref down to such a value in order to allow the approach Category of the 'frame to be listed as 1 below where it belonged.
There may now follow much discussion of 1 point something the stalling speed in the particular configuration depending on whose airworthiness or XAA regulations one is following, all I'm asking is a reasonable explanation of why the world's overruns are littered with disasters whereas the odd undershoot doesn't seem to feature in the stats. Please don't quote the San Fran disaster, they were just exploring a place all competent jocks wouldn't dream of going!
Maybe the airports' runway inspection routines may show up some inadvertent early (short of 300m) tyre marks but I would suggest this is less likely to happen if the guilty drivers had the orifice-puckering sensation of rocks/grass/gravel/lights/beach underneath them as they aim for the proper medium category transport touchdown point?
Still awaiting the comparison of stats to disprove the old adage that "there's nothing as useless as...the runway you've left behind".
But in the bright new dawn of the 21st century there are old lessons in aviation which are being forgotten.
In summary, the original posting asked about 737 overruns and I'm posing "why so fast and why so far in?" And we haven't even got to the tailwinds cases!
Read my original post and then work forwards from when jet transports were landed close to the threshold with minimal additions to Vref/Vapp until the current scene where 300 metres of paved runway real estate are wasted and for some odd reason a headwind is regarded as a special case requiring extra knots of IAS even though shear/turbulence is NOT a factor.
Probably I'm biased as my first post-military job was the Bae146 where the manual clearly stated "in order to make the scheduled landing distance...cross the landing threshold at Vref (airbrakes fully deployed) aiming to touchdown at Vref-7kts". Yes, that hyphen was a minus sign!
Whilst I appreciate the Boeings various may not use airbrakes whilst airborne, my abiding memory of transitioning onto the 74s and then 73s is that flying even at Vref over the landing threshold caused apoplexy amongst trainers and experienced capts, so that the only way to avoid criticism was to arrive at the threshold with minimum Vref+5kts and then everyone was happy.
Which has left me wondering why Boeing mentions Vref at all if it's never used. I suspect a ruse to get the paper Vref down to such a value in order to allow the approach Category of the 'frame to be listed as 1 below where it belonged.
There may now follow much discussion of 1 point something the stalling speed in the particular configuration depending on whose airworthiness or XAA regulations one is following, all I'm asking is a reasonable explanation of why the world's overruns are littered with disasters whereas the odd undershoot doesn't seem to feature in the stats. Please don't quote the San Fran disaster, they were just exploring a place all competent jocks wouldn't dream of going!
Maybe the airports' runway inspection routines may show up some inadvertent early (short of 300m) tyre marks but I would suggest this is less likely to happen if the guilty drivers had the orifice-puckering sensation of rocks/grass/gravel/lights/beach underneath them as they aim for the proper medium category transport touchdown point?
Still awaiting the comparison of stats to disprove the old adage that "there's nothing as useless as...the runway you've left behind".
But in the bright new dawn of the 21st century there are old lessons in aviation which are being forgotten.
In summary, the original posting asked about 737 overruns and I'm posing "why so fast and why so far in?" And we haven't even got to the tailwinds cases!
Join Date: Jun 2000
Location: last time I looked I was still here.
Posts: 4,507
Likes: 0
Received 0 Likes
on
0 Posts
... my abiding memory of transitioning onto the 74s and then 73s is that flying even at Vref over the landing threshold caused apoplexy amongst trainers and experienced capts, so that the only way to avoid criticism was to arrive at the threshold with minimum Vref+5kts and then everyone was happy.
Which has left me wondering why Boeing mentions Vref at all if it's never used.
I understand your comments. Surely the 1000' aiming point is to ensure a gear clearance height over the threshold and thus the approach lights shortly there before. Plonking it on the numbers with the gear many meters behind you and feet below is a challenging task fraught with tears.
In Boeing's FCTM they suggest a technique that is challenging and probably rarely achieved. Cross the threshold at Vref +5 + headwind & gust and touchdown at Vref + gust. The max addictive is +20. Dream on baby.
The technique suggested doesn't work. You arrive at 50' over the threshold at Vref + add ons. You false at 20' and close the TL's to idle so as to touch down at Vref or Vref + gust. So they some that this single technique can remove +5kts of whatever 1/2 the head wind was, which could be more. How is that possible for a constant drag scenario. If it removes 5kts how can it remove more than 5kts? Also, when committed to the landing, and n the flare, why is all the gust additive so important? For me, after 35 years on Boeing beasts Ive yet to achieve or seen achieved the perfect speed decay in the flare. It is a myth and perhaps only the Boeing sky gods can demo it. I suspect it is a numbers game to plug into the OPT landing performance calculation. Having said that, an over run is not caused by touching down in the correct place a couple of knots too fast; it is more likely caused by touching down too far, even at the correct speed, and then being too tardy with braking. Given all the buffers built into the calculations an over-run has to be either very different wind conditions than expected or gross mishandling; and that includes too fast or too long, usually both.
Which has left me wondering why Boeing mentions Vref at all if it's never used.
I understand your comments. Surely the 1000' aiming point is to ensure a gear clearance height over the threshold and thus the approach lights shortly there before. Plonking it on the numbers with the gear many meters behind you and feet below is a challenging task fraught with tears.
In Boeing's FCTM they suggest a technique that is challenging and probably rarely achieved. Cross the threshold at Vref +5 + headwind & gust and touchdown at Vref + gust. The max addictive is +20. Dream on baby.
The technique suggested doesn't work. You arrive at 50' over the threshold at Vref + add ons. You false at 20' and close the TL's to idle so as to touch down at Vref or Vref + gust. So they some that this single technique can remove +5kts of whatever 1/2 the head wind was, which could be more. How is that possible for a constant drag scenario. If it removes 5kts how can it remove more than 5kts? Also, when committed to the landing, and n the flare, why is all the gust additive so important? For me, after 35 years on Boeing beasts Ive yet to achieve or seen achieved the perfect speed decay in the flare. It is a myth and perhaps only the Boeing sky gods can demo it. I suspect it is a numbers game to plug into the OPT landing performance calculation. Having said that, an over run is not caused by touching down in the correct place a couple of knots too fast; it is more likely caused by touching down too far, even at the correct speed, and then being too tardy with braking. Given all the buffers built into the calculations an over-run has to be either very different wind conditions than expected or gross mishandling; and that includes too fast or too long, usually both.
Join Date: Sep 2017
Location: Bremen
Posts: 118
Likes: 0
Received 0 Likes
on
0 Posts
Having said that, an over run is not caused by touching down in the correct place a couple of knots too fast; it is more likely caused by touching down too far, even at the correct speed, and then being too tardy with braking. Given all the buffers built into the calculations an over-run has to be either very different wind conditions than expected or gross mishandling; and that includes too fast or too long, usually both.
I have no idea what considerations went into the setting of the touchdown standards, but I'd guess that putting the touchdown zone safely behind the threshold means the flare occurs over tarmac: maybe over soft ground, pilots would come out of the flare higher since they'd be afraid of hitting the dirt, and then "float" longer? and the extra 5 knots on the air speeds might be a safety allowance for sudden wind variations?
To get back to the original topic of this thread: the NLR-ATSI runway excursions page also has links to statistics on overruns/veeroffs for select years that show the aircraft type, and they're sortable. Sort first by aircraft type, then by phase and occurrence, and the incidents are easily countable: in 2013, the B737 had 10 landing overruns (and 3 veeroffs), while the A320 had 10 landing veeroffs (and 2 overruns). In previous years, the A320 had a lot less veer-offs, but the B737 overruns had comparable numbers, so the premise of this discussion seems correct.
I have been searching for figures on worldwide departures by aircraft type, but couldn't find any; fleet sizes are not that different, but departure numbers can still vary considerably if a type flies more short sectors. Does it seem plausible that the B737 would have 5 times as many departures as the A320?
