Are we still speaking of an executive configured, low payload, B737 on a 2100 m LDA?

tdracer:
We have it at MHT 06 also. Nothing on 24 which also has a drop off towards the river. The 300 ft on 06 was added during the runway expansion in 2001 if I recall correctly.

Thank you. I appear to have missed that bit. :\

A device intended to automatically help slow aircraft upon landing wasn’t operating when a jet carrying vice-presidential candidate Mike Pence skidded off a La Guardia Airport runway Thursday night, federal investigators said.

The pilots had to manually deploy panels that pop up on top of the wings, called spoilers, delaying by some seconds their effectiveness, the National Transportation Safety Board said Friday.

Mike Pence?s Jet Had Faulty Device - WSJ

And then the Penny dropped ...

With autospoilers inop there is normally a runway table that gives adjusted landing lengths. On some versions of the 737 there appear to be weight penalties associated with manual speed brakes, I'm thinking this probably depends on the rules in effect when the model was certified on the basis of the long-grandfathered 737 airworthiness certificate.

After the Southwest B-737-700 overrun at MDW in 2005, the FAA has been big on doing a landing performance assessment at the time of arrival.

Hopefully the crew explicitly did this, discussed and briefed the landing conditions and the autospoiler MEL.

And, remembered to raise the speedbrakes on landing.

EMAS is great stuff from the several saves in recent years. Like grooved runways, I'm sure it will eventually catch on overseas.

Was reading a number of 737 overrun cases the last few weeks. Just wondering if there was a good picture of an actual overrun through an EMAS when Mr Pence obliged.

Interesting to read in those reports how the NTSB covered post-dispatch-release and post-takeoff landing performance assessment issues already for a number of years, and @Airbubba pointing out that the FAA is following up.

For those interested. The spoiler issues from literature (at least from what i am reading) amongst others shows a number of important issues. First arming spoilers at all, and second armed spoilers automatically deploying but retracting again, and third automatically retracting spoilers with or without the crew manually deploying them again.

Will be interesting to compare for instance the case of American Airlines 1420 (MD82) of 1999 with the present case.

[tangent alert]

So what's the expected result if an a/c lands short on a rwy w/EMAS .. that is, the MLG touches down on the stuff?

Well, with the particular EMAS in question at the approach end of LGA 04, if you are low/short enough to touch down on it, you likely already took out the top of a semi or bus on the highway (Grand Central Parkway) that is only 300 feet or so south of the EMAS end.

But in general, depends on whether you plant the landing hard, or grease it on, such that the full weight only settles on the wheels after passing the EMAS.

Edit for correction.....

Durrh! - peekay is correct. Picture shows ramp (also blast deflector to prevent take-off thrust in the other direction stripping off the EMAS) and EMAS positioning on top of runway surface:

http://www.ainonline.com/sites/defau...citation-3.jpg

Is there a 'ramp' under the EMAS to ease the transition to the runway if you land short?

Or would it be like the MC-130 that landed at night in Iraq on the closed runway? Closed because there was a 4' deep ditch across the runway.

Iraq C-130 Crash Photos

There is no "ramp" or "step up" if you land short. It's the other way around -- EMAS actually sits "on top" of the paved surface. The "bottom" (base) of the EMAS is at the same elevation as the runway.

The issue if you land short is if the EMAS bed is too soft (think of landing into soft mud that's unable to withstand the aircraft's weight -- you can easily lose control). So EMAS including its base must be constructed to some minimum strength and density.

Since EMAS is actually "on top" of the runway surface, then there is in fact a ramp, but on far side. I.e., if you land long, there is a gentle ramp past the runway end that supports the plane up onto the EMAS bed.

Is there a set height to cross the threshold or on a short runway can the PF use discretion and come in a little lower?

50 feet. Not much room for any lower with regards to tail clearance. And it would not be an authorized technique anyhow.

Short version: yes, we can.

Ducking under is a BIG NO NO nowadays.

Ducking under is OK and used by professionals on a day to day basis where I work. E.g. a contaminated runway with displaced threshold. Plenty of flat surface under you before the 'real' threshold. The point is not to land on it but land earlier than normal to maximize stopping distance. You can gain a couple of hundred meters if needed. If visual references are poor, then you might not want to try it. Your call.

I certainly concur with JW411 that ducking under the 3deg approach path is a very big no-no.

To fine-tune this point, if one decides to do so or it is condoned at one's carrier, one must know one's aircraft and the runway.

One never, ever ducks under with a wide body due to gear clearances at the threshold - THAT is a no-no. If one is feeling the need to do so because one has even slight doubts about stopping distances, redo the actual landing distance calculations using all applicable factors in the charts, (which normally do take reverse into consideration, at least on the Boeing).

If it is close, one should not be there in the first place. Don't do the approach, period. How one then resolves that, (divert, different runway, hold), is a PIC decision.

With smaller transports, (B737/A320, etc) one may make a decision to do so if one knows the airport and one's clearances and knows what a displacement of say a half-dot low means in actual height above the threshold, (a dot low at the threshold is a big no-no even though it can be technically done).

In those rare situations where one diverges from SOPs, one must think, "Now is the 30" I have in hand, which I may wish I had, 45" from now..."

There is simply no percentage in hitting a light or worse, just to satisfy your passengers' need to get to their destination. I should think that very few companies these days will question the resulting diversion if that's what it ends up being.

Can you elaborate on what you mean there ? Surely a dot low at the threshold is better than a dot low at any time prior to the threshold? From memory I think a dot low is only about four feet low by the time you are at the threshold on a standard 3 degree slope.

A friend of mine has heard it touched down well into the runway leaving <1000m to stop. Is that correct?

172, there are many issues with 'duck under'.

• The threshold crossing altitude considers the preceding obstacle free surface, penetrate that at you own risk.
• A duck under manoeuvre destabilises the approach; there is plenty of evidence that this adds risk to the landing.
• If you feel that you need an extra 'two hundred meters' then the pre-landing assessment has been misjudged; go around.

The objective of calculating landing distance with appropriate safety margins is that if there are no aircraft failures or gross pilot mishandling then the landing risks are minimised. The safety margins should accommodate most system failures or mishandling, but perhaps not both together. Then and only then might EMAS be considered, but this is a risk mitigation strategy for inadequate or special emergency overrun areas, not for pilots to plan on having.

framer, you assume that duck under can be done whilst maintaining a 3 deg slope; and perhaps overlook that the GS abeam is angular. Thus linear extrapolation of a 'little bit low' at the threshold could be much larger before that.

Landing closer to the Threshold than the 3-400m touchdown zone was a question for judgement on the day, and only on a very clear visual approach. A Devil's Advocate comment might be: "if the 3 most useless things to a pilot are 1. runway behind you, 2. sky above you & 3. fuel in the bowser," then why is No.1 only for takeoff?
OK, I know all the arguments about obstacle clearance and safety zone penetration, and beat it into my students for years. Now, OFDM that includes 'below G.S' data has stamped that out on ILS. However, I remember a day many years ago, before Big Brother, going into Inverness (short) in winter (patches of ice & snow and an 'finger in the wind' BA assessment) with no headwind, even swirling: (a previous F27 had said it was OK) we decided that leaving excessive tarmac behind us at touchdown was not desirable, and we might 'pinch a bit'. This was before OFDM and an NPA in any case. Neither of us considered this a dangerous or destabilising manoeuvre. Risking going off the end was considered the worse option.
RW32L MAD has a huge displaced threshold. The displacement is a short runway in itself. Totally clear of any obstruction. So what would you do if you had an anti-skid landing to make? Would you leave 300-400m behind you when Mk-1 eyeball says the air underneath you is clear & free. I'm not talking of death defying dives, never; but equally I can't say never to pinching a bit. There need to be mitigating and extenuating circumstances. As a matter of course on a clear & dry day with fully functional a/c? No.
Watching the landings in ST. Maarten makes one wonder. Look at the wheel height over the beach B747 and wonder if they've flown on the slope all the way down. Pinching a bit on that runway, in such a high eye height, would be fraught with danger. If you do it correctly, on speed, with a head wind, on a clean & dry runway with all the buffers included, there should be no problem to the skilled.
There were some very short looking runways in the european tourist network where we took B767. They did look short at 2-3 miles out, but the brakes are made for MTOW RTO's so stopping a light weight landing was never a problem, if you arrived on schedule and not 5 secs late. 2 seconds early was not required.