Depending on how quick of a turn this was and how hot the ambient temperature is outside, it is possible that the brakes haven't cooled down sufficiently since the previous landing.
Rare, but not unheard of...
Had this happen once (overheated brakes due to quick turn) but didn't play out quite like what the OP describes.
Very fast turnaround (25 minutes??) on a hot day in DEN. After we reached cruise altitude, the pilot lowered the gear (lots of wind noise!) and explained that a sensor in the wheel well indicated excessive heat and they wanted to cool the brakes for a while.
Now of course we didn't really know at what point the sensor had indicated high heat and how the decision was made; could have been that it was known and they were just waiting to reach cruise to drop gear and cool them. Seems less surprising to sense the heat in the enclosed space (closed wheel well) than while taxiing about?
Depending on how quick of a turn this was and how hot the ambient temperature is outside, it is possible that the brakes haven't cooled down sufficiently since the previous landing.
Rare, but not unheard of...
Happened to me on a Frontier A319, out of DEN approx. 2 weeks ago. We sat on the 8 pad for maybe 20 minutes prior to an 8pm-ish departure. Pilot stated brakes weren't cool enough from previous landing.
There was a UA 733 or 735 next to us on the pad as well, one might assume same reason? (or maybe they were "waiting for their numbers" )
Same thing happened to me on a TED flight a few months back and it was not a quick turn. We had to sit on the tarmac for about half an hour while they cooled.
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I'm sitting on the tarmac on a Ted A320, allegedly because the brakes overheated during taxi, and they need to cool before takeoff. I have never heard of brakes overheating during a 10mph taxi before. Could this be a legitimate safety concern, or is it another way for pilots to mess up operations in protest?
The engines are off "to save fuel," and the cabin is heating up. No Channel 9 to know what's going on, and only minimal announcements from the cockpit. I hate to throw around accusations, but this feels fishy.
The Airbus has brake temperature gauges. When their temp. reaches 300 degrees celsius (572F), there is an operational restriction for taking off. The heat is cumulative. Recent landings, short runways (SNA, JAC, etc) with more brake application time or intensity, long taxis, and hot days with high altitudes (DEN, JAC, etc) cause brake heat to accumulate faster than it dissipates.
If the brakes get to or over 300C, takeoff is not allowed until they cool below 300C. The temp sensor/indication combination lags a little, so it's possible to take off with the brakes showing below 300c but then the delayed indication goes over 300C, and we either have to drop the gear again, while observing airspeed and altitude restrictions until the indications drop below 300C. Occasionally it potentially affects 2nd segment climb performance restrictions as well, since we'll be not retracting the gear on schedule. The reason for the performance restrictions is that the planes are all certified to meet certain performance criteria with an engine failure at a few knots prior to pulling the nosewheel off the ground on the takeoff roll and still meet a bunch of controllability and climb rate requirements. Except under some unusual combinations of outside air temperature, air density, weight, and takeoff clearway plane and obstacle clearance combinations, they will perform adequately with the Dunlops a' danglin' (semi-humorous way of saying the gear's down).
There are a lot of other factors involved as well, such as brake energy limits based on those above factors plus temperature-related brake effectiveness that's considered for when we would stop the takeoff instead of continue in the event of an engine failure.
We can see the up trend when taxiing, so if we see that we can get airborne before they hit 300C, we'll go ahead and take off and hang the gear until the temp peaks, then drops below 300C.
I haven't flown the 'Bus for almost a year, but remember that stuff. The 767-300 has brake temp sensors, but the 757 doesn't. I landed in Lihue a few days ago, and with it's short runway and 'self-critiquing' drop into the ocean a little beyond the end of the runway, we cooked 'em, but the plane had a few hours of ground time so no biggie. Also, the gauges are qualitative (0 thru 5) whereas on the 'Bus, they're quantitative (0 thru 300C).
When you bring a 'Bus in that another crew will take, you exercise proper blue-room etiquette (try not to stink it up too bad for the next guys or gals).
The only thing fishy is the crew meals, with the accompanying and highly convenient $5.25 deduction from our paychecks for same. I like mine heated to 300C, just to ward off answering the White Porcelain Telephone on the next layover.
Airbus offers brake cooling fans as an option, and they're cheaper than executive retention bonuses. Go figure.
Who likes their airplanes, and why? I like the 'Bus because it doesn't have that darn steering wheel in my lap. It's got a sidestick for flying with, and a nice pull-out tray table for eating the aforementioned crew meals, but she's not a Hawaii machine. nice to fly, or nice to layover: THAT is the question!
Freshairborne (or not so fresh today...after flying all night from aforementioned Lihue)
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These are my own observations and/or opinions, and not necessarily those of the Air Line Pilots Association or UAL Corp.
I'm sitting on the tarmac on a Ted A320, allegedly because the brakes overheated during taxi, and they need to cool before takeoff. I have never heard of brakes overheating during a 10mph taxi before. Could this be a legitimate safety concern, or is it another way for pilots to mess up operations in protest?
The engines are off "to save fuel," and the cabin is heating up. No Channel 9 to know what's going on, and only minimal announcements from the cockpit. I hate to throw around accusations, but this feels fishy.
Don't recall the plane type but this happened to me years ago. We parked for a bit hoping the sensor would go off, took awhile, it finally did but when they tried to take off it went again. In our case the overheated brakes turned into a flat tire that the Captain had previously assured was definitely not the case because 'he'd be able to tell'. Oh, well.
Ops had their usual screw up of go to the gate, don't go to the gate. We ended up with 4 hours (yes FOUR!) on the tarmac when they made their decision, sent us to the pen and had the trucks come over to do the tire switch. That we never even felt the plane being lifted for that tire change was pretty cool. The FAs were short handed that flight but did a great job keeping tempers calm, showing the movies (we ended up seeing everything they had as we still had 4 hours of flying once we finally got to take off). I had an aisle seat in coach, but think this was before the days of E+ and recall it was a sardine can for everyone. I was next to some poor souls connecting from some europe flights who hadn't slept in 20+ hours. It was a rough evening.
I'm sitting on the tarmac on a Ted A320, allegedly because the brakes overheated during taxi, and they need to cool before takeoff. I have never heard of brakes overheating during a 10mph taxi before. Could this be a legitimate safety concern, or is it another way for pilots to mess up operations in protest?
The engines are off "to save fuel," and the cabin is heating up. No Channel 9 to know what's going on, and only minimal announcements from the cockpit. I hate to throw around accusations, but this feels fishy.
Unfortunately I knew this was going to be happening more often. Freshairborne answered the brake temperature question well, here is what's happening now at United. Management decided to change their SOP just a couple weeks ago to having us land Flaps 3 instead of Flaps Full from now on, to save fuel. Now, I did some calculations and the savings are almost nil on a visual approach, and on an instrument approach, you might save about 6 gallons of fuel, so that is about $24 by using Flaps 3. However, you land faster and you have to use the brakes more, thus heating them up more quickly and to higher temps. The Airbus's brakes are good, but they heat up VERY QUICKLY, thus the reason they come installed with cooling fans which UNITED MANAGEMENT had removed when they bought them.
We are limited to 300 degress on a brake prior to takeoff, and with folks following new guidance for F3 landings, having to sit and wait for brakes to cool for the next takeoff will be the new norm until winter time. Me personally, I still use Flaps Full for landing unless it is a long runway and cool outside.
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Last edited by aluminumdriver; Aug 11, 08 at 3:12 pm.
DEN is a work out in the summer, taxiing for a distance will do it there! You overheat the brakes, your fuse plugs ( The tires fuse plugs ) will melt then the air is let out of the tires to preclude tires from blowing up. Nothing to do with labor relations , it is all out of the book!
Last edited by joewildblue; Aug 11, 08 at 3:06 pm.
Thanks for the detailed and informative answers regarding the hot brakes on the Airbus. The aircraft sat at the gate for about 90 minutes between flights, so I didn't even think it was possible for the brakes to still be cooked from the last flight. Learn something new every day!
Thanks for the detailed and informative answers regarding the hot brakes on the Airbus. The aircraft sat at the gate for about 90 minutes between flights, so I didn't even think it was possible for the brakes to still be cooked from the last flight. Learn something new every day!
It might have been just one brake that was too hot. That's not unusual for one brake or a certain side to be hotter than the other side and with it hot out, they just don't cool off very quickly.
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These views are my own and do not represent the views of United Airlines or the ALPA.
Thanks for the detailed and informative answers regarding the hot brakes on the Airbus. The aircraft sat at the gate for about 90 minutes between flights, so I didn't even think it was possible for the brakes to still be cooked from the last flight. Learn something new every day!
That explains alot to me as well. I have had two aborted take off's on the 320 and both times the pilot returned to the gate to let the brakes cool and that here in foggy SFO.
Maybe this has been asked before but on the 747, right after take off's I always notice a shimmy like a left to right movement or like the wings are flexing. I notice it more in F/C class than in Y, but perhaps it is because I am in E+. What is that?
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Unfortunately I knew this was going to be happening more often. Freshairborne answered the brake temperature question well, here is what's happening now at United. Management decided to change their SOP just a couple weeks ago to having us land Flaps 3 instead of Flaps Full from now on, to save fuel. Now, I did some calculations and the savings are almost nil on a visual approach, and on an instrument approach, you might save about 6 gallons of fuel, so that is about $24 by using Flaps 3. However, you land faster and you have to use the brakes more, thus heating them up more quickly and to higher temps. The Airbus's brakes are good, but they heat up VERY QUICKLY, thus the reason they come installed with cooling fans which UNITED MANAGEMENT had removed when they bought them.
We are limited to 300 degress on a brake prior to takeoff, and with folks following new guidance for F3 landings, having to sit and wait for brakes to cool for the next takeoff will be the new norm until winter time. Me personally, I still use Flaps Full for landing unless it is a long runway and cool outside.
That's a ridiculous cost-saving venture. I think I have noticed it too as landing have been much louder when the brakes are applied. Coming into SFO the other day was one of the smoothest touchdowns in recent memory though a very loud and shaky slowdown. I even noticed that we were coming in awfully fast.
That's a ridiculous cost-saving venture. I think I have noticed it too as landing have been much louder when the brakes are applied. Coming into SFO the other day was one of the smoothest touchdowns in recent memory though a very loud and shaky slowdown. I even noticed that we were coming in awfully fast.
What was the headwind and crosswind component, your groundspeed, and what was your airspeed indicator showing? How about the ref speed and target speed? Did you have the right correction added for the average gust speed?
Freshairborne
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as to the discussion of landings and hot brakes......
silly question but at those airports with long (say +10-12,000 feet) runways, is it more economical to to use the brakes by themselves, the brakes with the thrust reversers or the thrust reversers alone (assuming of course that you didn't land long and have sufficient runway to roll out). i've been on flights were the t/r's were not deployed and only the brakes were used but don't think i've been on one where only the t/r's were used. also, is something like using only t/r's permitted (other than in an emergency when you lost your brakes)
thanks
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