EMAS Save at ORD
Doors to Automatic, thanks (#20). This reinforces the need for accurate qualification of data presented in Pprune (#11), i.e. ‘ground roll’ vs the ‘landing distance (factored/unfactored)’.
The assumption that the landing will occur 1000ft beyond the threshold is an important criterion, but it is affected by threshold crossing height, airspeed compared with ref, and wind; thus these and other aspects have to be considered before the ground roll distance.
Most importantly you do not qualify the runway condition, particularly where an increasingly wet runway results in deteriorating braking performance.
Although safety factors in landing distances indicate a 15% increase (1.67-1.92) between dry and wet, this does not mean that the achievable distances vary in the same proportion. Dry data is the result of flight test measurement, wet data uses a factor and might be checked with calculations, but this does not account for all combinations of ‘wet’ friction.
Thus with an airborne distance greater than 1000ft, ground roll (wet) considerably longer than 3000ft, and perhaps with a safety factor approaching 2.0 (braking level, flying accuracy, etc, etc), all indicate that a landing within 8000ft is not without risk, i.e. not a ‘good margin’.
The assumption that the landing will occur 1000ft beyond the threshold is an important criterion, but it is affected by threshold crossing height, airspeed compared with ref, and wind; thus these and other aspects have to be considered before the ground roll distance.
Most importantly you do not qualify the runway condition, particularly where an increasingly wet runway results in deteriorating braking performance.
Although safety factors in landing distances indicate a 15% increase (1.67-1.92) between dry and wet, this does not mean that the achievable distances vary in the same proportion. Dry data is the result of flight test measurement, wet data uses a factor and might be checked with calculations, but this does not account for all combinations of ‘wet’ friction.
Thus with an airborne distance greater than 1000ft, ground roll (wet) considerably longer than 3000ft, and perhaps with a safety factor approaching 2.0 (braking level, flying accuracy, etc, etc), all indicate that a landing within 8000ft is not without risk, i.e. not a ‘good margin’.
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Mexicana
I was a non-rev pax on an American flight from Cancun that landed on 4R at ORD 40 minutes prior to Mexicana. At the time the WX was still nice, with calm winds, but thunderstorms were approaching from the Northwest. On my way home from the airport I drove (northwest bound) through torrential rain for 20 minutes. My guess is that Mexicana landed into the approaching WX. I am based in ORD and have experienced many WX systems approaching... ATC will keep you going until you tell them no... I guess Mexicana maybe thought they could beat the WX... Just a guess.
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4R tecnique at KORD
I have operated in and out of O'Hare for almost 20 years flying aircraft such as 727, 757/767, 747 and currently A320/319.
Whilst landing 4R, the local controller normally tells the crew to "roll to the end". All well and good...You know you have traffic behind you, the aircraft will die in 8,000 feet of concrete, so you tend to use idle reverse, low braking and meter the roll out to the end..
Now, the part that "may" have gotten MX in trouble. If you do the above and the runway is even slightly contaminated, it gets very slick, the last 1,000 feet or so. I anticipate this and tend to have my speed adjusted accordingly so as not to slide on the painted surfaces etc...
I am in no way trying to guess what happened or attempting to find fault with anyone. I am just describing real world operations on a runway that I am extremely familiar with.
Cheers,
Slats
Whilst landing 4R, the local controller normally tells the crew to "roll to the end". All well and good...You know you have traffic behind you, the aircraft will die in 8,000 feet of concrete, so you tend to use idle reverse, low braking and meter the roll out to the end..
Now, the part that "may" have gotten MX in trouble. If you do the above and the runway is even slightly contaminated, it gets very slick, the last 1,000 feet or so. I anticipate this and tend to have my speed adjusted accordingly so as not to slide on the painted surfaces etc...
I am in no way trying to guess what happened or attempting to find fault with anyone. I am just describing real world operations on a runway that I am extremely familiar with.
Cheers,
Slats
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Landing with 8,000 feet of runway doesn't seem very hard at ORD elevation. A320's have had an awful lot of overruns in the last year. Maybe all that automation doesn't give the pilots the tools to deal with problems with computer conflicts that Boeing lets pilots override. I don't hate airbus but I am very happy I never flew one.
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Resurrecting an old thread....
Have been reading up on NTSB reports on EMAS saves. There has been 9 of them so far. Usually there is a report on the NTSB site but I can't find one for this or the Polar 747 at JFK which is surprising because even small single engine accidents have some sort of info on the NTSB site.
However, I have had some difficulty on occasion finding a report for a while so perhaps someone out there knows if there is any further info on these two serious incidents.
Thanks.
Have been reading up on NTSB reports on EMAS saves. There has been 9 of them so far. Usually there is a report on the NTSB site but I can't find one for this or the Polar 747 at JFK which is surprising because even small single engine accidents have some sort of info on the NTSB site.
However, I have had some difficulty on occasion finding a report for a while so perhaps someone out there knows if there is any further info on these two serious incidents.
Thanks.
Usually there is a report on the NTSB site but I can't find one for this or the Polar 747 at JFK which is surprising because even small single engine accidents have some sort of info on the NTSB site.
However, I have had some difficulty on occasion finding a report for a while so perhaps someone out there knows if there is any further info on these two serious incidents.
However, I have had some difficulty on occasion finding a report for a while so perhaps someone out there knows if there is any further info on these two serious incidents.
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Originally Posted by DaveReidUK
Correct, there is no record in either the NTSB or FAA AIDS database for either of those two incidents
Regardless if there was little damage to the aircraft, the cost to repair an EMAS bed, from what I've heard, is very expensive.
600 ft of EMAS is used to prevent overruns on either end of runway 10R/28L at FLL.
The photo below was taken from NE 7th Ave, courtesy of Google Maps, looking up at the EMAS extension on the far east end of FLL's new south runway. The dimensions of the safety area in the photo are approximately 600 ft Long X 500 ft Wide X 55 ft High from grade level.
It's designed to stop a maximum gross weight B-777-200 from going over the edge with an EMAS entry speed of 70 kts.
Last edited by wanabee777; 5th Dec 2015 at 09:00.
