ATA 757 overrun at Midway
Someone's comment about how seldom we read about any incident at Midway seems accurate. As to another person's comment that Midway is safe, maybe so, if all wind reports are accurate, it is dry and both pilots brief each other on the vital need to avoid any floating or bursts of throttle while in the flare-and they never make a serious error in judging which flair technique to use. I've told FOs in our 60's vintage twin-turbofan machines that if there is ever any doubt about stopping ability at Midway (and no option to circle in VMC to 22R...), i.e. winds, heavy plane, water or snow etc on the landing runway, then we are going around and/or diverting next door to O'Hare etc. If there is any similar question at DCA or LGA, you have much longer runways nearby at airports which definitely qualify as safe airports. The inside of Midway's terminal now has a nice selection of places to eat and find chocolate coffee etc, but what a hazardous, cramped, dump of an airport which is waiting for you outside.
There is the additional hazard of so many runways and almost identical parallel taxiways to cross, when certain runways are in use. You must constantly turn your head because of so many almost identical stretches of concrete. At that airport, you often must either stop your taxi, in order to safely do most checklists, or wait until in the hold-short area. Make sure the Captain tells you about his "plan" before you taxi out of Midway, Boston, etc.
In my opinion, there is no excuse for heavy transport operations into any of these three airports, (and we all know that the US, among other countries, has been in the "jet-age" for decades) under any and all weather conditions with the present physical limitations, except by rationalizing by using a "Third World" mentality, knowing that there has always been money available to lengthen at least one runway at any of these, but political expediency and convenience is sometimes much more important than "normal" safety in the good old USA. If you don't believe me, read about what Chicago Mayor Richard Daley JR did in the middle of the night to permanently shutdown/destroy Meigs Field by downtown Chicago. As for questionable info given to pilots at another very small airport, one major airline decided, due to unreliable reports on runway de-icing treatment resulting in an incident, to avoid Traverse City, Michigan in the winter, or at least not use "mainline" equipment.
Not long ago at SAT/San Antonio, on a STAR for runway 12R, we figured out that the tailwinds reported on the ATIS did not sound right. When we asked the tower controller about it, they said that something was wrong with the equipment and then immediately were vectored southeast, in order to now land on runway 30L. Wind reports can be in error anywhere, with our new-fangled high tech equipment used by the tower controllers.
There is the additional hazard of so many runways and almost identical parallel taxiways to cross, when certain runways are in use. You must constantly turn your head because of so many almost identical stretches of concrete. At that airport, you often must either stop your taxi, in order to safely do most checklists, or wait until in the hold-short area. Make sure the Captain tells you about his "plan" before you taxi out of Midway, Boston, etc.
In my opinion, there is no excuse for heavy transport operations into any of these three airports, (and we all know that the US, among other countries, has been in the "jet-age" for decades) under any and all weather conditions with the present physical limitations, except by rationalizing by using a "Third World" mentality, knowing that there has always been money available to lengthen at least one runway at any of these, but political expediency and convenience is sometimes much more important than "normal" safety in the good old USA. If you don't believe me, read about what Chicago Mayor Richard Daley JR did in the middle of the night to permanently shutdown/destroy Meigs Field by downtown Chicago. As for questionable info given to pilots at another very small airport, one major airline decided, due to unreliable reports on runway de-icing treatment resulting in an incident, to avoid Traverse City, Michigan in the winter, or at least not use "mainline" equipment.
Not long ago at SAT/San Antonio, on a STAR for runway 12R, we figured out that the tailwinds reported on the ATIS did not sound right. When we asked the tower controller about it, they said that something was wrong with the equipment and then immediately were vectored southeast, in order to now land on runway 30L. Wind reports can be in error anywhere, with our new-fangled high tech equipment used by the tower controllers.
Last edited by Ignition Override; 13th Sep 2003 at 12:02.
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FLYCHICAGA
"We takeoff and land with tailwinds about 50% of the time."
Do you work for Southwest by chance? That is a figure that I have never heard from anyone.
"What I believe came into the factors here was that they landed a bit long and did not have use of the thrust reversers. But I am not going to speculate."
You just did speculate. By the way, since when have thrust reversers ever been used to certify an aircrafts ability to stop? I am sure someone will correct me, but isn't stopping distance based on brakes and spoilers without the use of reverse thrust. At least Boeing and Douglas uses that criteria.
" People look at it as if it is dangerous, however nothing is farther from the truth."
I don't know if people consider it dangerous or not, however it is looked at as extremely critical by knowledgeable people. There is a reason that operations were shifted to O'hare many years ago. I don't know if MDW is the most critical airport to fly large aircraft out of, but it is certainly one of the top 3 in the USA. The newer transport aircraft handle MDW very easily on landing if it is a nice dry pleasant day. Landing in the winter on ice and snow with gusting winds is another story. Landing one of the older generation transports like the 727-200 or 707 is quite frankly not the same thing. I still consider the hot summer day takeoff at max gross the critical maneuver out of MDW, there is simply nowhere to go if everything does not work properly. MDW is an airport that is completely unforgiving unless everything is working perfectly. Fortunately for most of our newer pilots that have only flown the newer generation aircraft, they are extremely reliable.
"We takeoff and land with tailwinds about 50% of the time."
Do you work for Southwest by chance? That is a figure that I have never heard from anyone.
"What I believe came into the factors here was that they landed a bit long and did not have use of the thrust reversers. But I am not going to speculate."
You just did speculate. By the way, since when have thrust reversers ever been used to certify an aircrafts ability to stop? I am sure someone will correct me, but isn't stopping distance based on brakes and spoilers without the use of reverse thrust. At least Boeing and Douglas uses that criteria.
" People look at it as if it is dangerous, however nothing is farther from the truth."
I don't know if people consider it dangerous or not, however it is looked at as extremely critical by knowledgeable people. There is a reason that operations were shifted to O'hare many years ago. I don't know if MDW is the most critical airport to fly large aircraft out of, but it is certainly one of the top 3 in the USA. The newer transport aircraft handle MDW very easily on landing if it is a nice dry pleasant day. Landing in the winter on ice and snow with gusting winds is another story. Landing one of the older generation transports like the 727-200 or 707 is quite frankly not the same thing. I still consider the hot summer day takeoff at max gross the critical maneuver out of MDW, there is simply nowhere to go if everything does not work properly. MDW is an airport that is completely unforgiving unless everything is working perfectly. Fortunately for most of our newer pilots that have only flown the newer generation aircraft, they are extremely reliable.
Last edited by dudly; 13th Sep 2003 at 04:18.
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Note on anti-skid brakes:
Aircraft making a full performance stop with the use of anti-skid brake systems usually leave skid marks. The hydraulic pressure is rapidly cycled to prevent the wheels from 'locking up'. Braking Coefficient of a locked wheel is less than that of a turning one. A turning wheel will still leave rubber behind if it is turning at a rate which is less than that required by the forward movement of the aircraft. Anti-lock brakes would be a better name. Examine photos from most runway excursion incidents and you will see skid marks. You may see 'chattering' of the marks which is another indication of system operation. If you see long spans of nothing it is because the pilot may have started to pump the brakes in a futile attempt to stop - or there was a system malfunction.
Try not to armchair quarterback on incident or accident too much before the official report and remember: Accidents are usually the result of more than one thing/ system malfunction (brakes, spoilers, reversers)/ unexpected wx / poor briefing / unexpected distractions / fatigue / etc etc..
Aircraft making a full performance stop with the use of anti-skid brake systems usually leave skid marks. The hydraulic pressure is rapidly cycled to prevent the wheels from 'locking up'. Braking Coefficient of a locked wheel is less than that of a turning one. A turning wheel will still leave rubber behind if it is turning at a rate which is less than that required by the forward movement of the aircraft. Anti-lock brakes would be a better name. Examine photos from most runway excursion incidents and you will see skid marks. You may see 'chattering' of the marks which is another indication of system operation. If you see long spans of nothing it is because the pilot may have started to pump the brakes in a futile attempt to stop - or there was a system malfunction.
Try not to armchair quarterback on incident or accident too much before the official report and remember: Accidents are usually the result of more than one thing/ system malfunction (brakes, spoilers, reversers)/ unexpected wx / poor briefing / unexpected distractions / fatigue / etc etc..
Accident investigation statistics for runway excursion / overrun are characterised by several similarities, some of which may apply to this accident. Tailwinds and (wet) concrete runways.
It appears that the landing at Midway was on a dry runway; however, how often have pilots been caught out by a change in braking coefficient? The difference between a good ‘black top’ runway and a concrete surface could be 0.2 mu. The larger differences occur at higher speeds – note ground speed – tailwind landings. Tailwinds always reduce the safety margins; 150% landing distance factors are applied. A small change (5 kts) in a reported light tail wind could easily cause an aircraft, heavier than usual, to rapidly approach the limiting landing performance, Then of course the crews performance has to be considered; do they always land at the assumed touchdown point or use max braking …. ?
Are crews now over-familiar with the standard black top runways or the more recent high friction course (HFC) surfaces that they forget that there are still some poor runway surfaces out there? I have no recent knowledge of Midway, but on a wet day even with grooving, the reduction in mu could approach 0.4; maybe similar to the difference between good HFC and un-grooved concrete on a dry day. Then there is rubber or dust to add to the equation.
The other hazard with concrete is that with aging the blocks sink / settle in the centre enabling puddles of water to form. Similarly with the bitumen edges they can dam water puddles to an extent that a runway described as ‘wet with water patches’ should be treated as flooded.
Safe landings – into wind.
It appears that the landing at Midway was on a dry runway; however, how often have pilots been caught out by a change in braking coefficient? The difference between a good ‘black top’ runway and a concrete surface could be 0.2 mu. The larger differences occur at higher speeds – note ground speed – tailwind landings. Tailwinds always reduce the safety margins; 150% landing distance factors are applied. A small change (5 kts) in a reported light tail wind could easily cause an aircraft, heavier than usual, to rapidly approach the limiting landing performance, Then of course the crews performance has to be considered; do they always land at the assumed touchdown point or use max braking …. ?
Are crews now over-familiar with the standard black top runways or the more recent high friction course (HFC) surfaces that they forget that there are still some poor runway surfaces out there? I have no recent knowledge of Midway, but on a wet day even with grooving, the reduction in mu could approach 0.4; maybe similar to the difference between good HFC and un-grooved concrete on a dry day. Then there is rubber or dust to add to the equation.
The other hazard with concrete is that with aging the blocks sink / settle in the centre enabling puddles of water to form. Similarly with the bitumen edges they can dam water puddles to an extent that a runway described as ‘wet with water patches’ should be treated as flooded.
Safe landings – into wind.
