Luftfahrer From Germany, joined Mar 2009, 965 posts, RR: 5 Posted (2 years 3 weeks 4 days 21 hours ago) and read 4384 times:
Hello everyone,
London City (LCY) has a very short runway: only 1508m meters long. Still, fairly sizeable aircraft such as the Embraer E190 or the Airbus A318 are based there and are operated into this particular airport on a daily base. I wondered whether a high amount of braking action was needed in order to achieve a safe deceleration. If so, to what degree does this affect the brake temperature after landing? And are the brakes of aircraft that are operated several times a day into LCY more prone to wear and tear?
tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 81 Reply 1, posted (2 years 3 weeks 4 days 21 hours ago) and read 4381 times:
Quoting Luftfahrer (Thread starter): I wondered whether a high amount of braking action was needed in order to achieve a safe deceleration.
All other things being equal, yes, you need to brake harder on a shorter runway.
Quoting Luftfahrer (Thread starter): If so, to what degree does this affect the brake temperature after landing?
There's a direct (nearly linear) relationship between energy absorption and brake temperature. The total amount of energy to be dissipated is a function of just your approach speed and weight, but the proportion that goes into the brakes (vs. amount into reverse thrust and drag devices) will be different. Shorter runways tend to put more into the brakes, leading to higher brake temperatures.
Quoting Luftfahrer (Thread starter): And are the brakes of aircraft that are operated several times a day into LCY more prone to wear and tear?
If they're steel, probably. Steel brakes wear in proportion to energy absorbed. Carbon brakes shouldn't make much difference, since they wear in proportion to number of applications (one cycle wear is about the same, regardless of how much energy went into the brake on that cycle).
Luftfahrer From Germany, joined Mar 2009, 965 posts, RR: 5 Reply 2, posted (2 years 3 weeks 4 days 15 hours ago) and read 4198 times:
Thanks Tom.
Quoting tdscanuck (Reply 1): Shorter runways tend to put more into the brakes, leading to higher brake temperatures.
Would you say that the temperatures rise so much that it becomes a problem, i.e. a longer cool down phase is needed, possibly extending the turnaround time?
Quoting tdscanuck (Reply 1): Steel brakes wear in proportion to energy absorbed. Carbon brakes shouldn't make much difference
Seeing the E-Jets and the Airbus as modern aircraft, can one assume that they are equipped with carbon brakes?
Marius
Et là tu montes encore plus haut et ça persiste, alors on vole
Viscount724 From Switzerland, joined Oct 2006, 21464 posts, RR: 24 Reply 4, posted (2 years 3 weeks 4 days 12 hours ago) and read 4104 times:
Quoting Luftfahrer (Thread starter): London City (LCY) has a very short runway: only 1508m meters long. Still, fairly sizeable aircraft such as the Embraer E190 or the Airbus A318 are based there and are operated into this particular airport
Dozens of even larger aircraft, up to 737-800 size, operate daily to/from Rio de Janeiro's city-center Santos Dumont airport where the longest runway is even shorter (1323m, 4341 ft) than at LCY and ends in water at both ends. Brakes and reverse thrust must also get heavy use there.
tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 81 Reply 5, posted (2 years 3 weeks 4 days 8 hours ago) and read 4009 times:
Quoting Luftfahrer (Reply 2): Would you say that the temperatures rise so much that it becomes a problem, i.e. a longer cool down phase is needed, possibly extending the turnaround time?
It all depends on landing weight...for the types of short/medium-haul jets that go in and out of there, that are built for fast turns and aren't tremendously heavy, I wouldn't expect it to be a big problem.
But yes, you do need to monitor brake energy and that can push up your turn time.
Quoting Luftfahrer (Reply 2): Seeing the E-Jets and the Airbus as modern aircraft, can one assume that they are equipped with carbon brakes?
Usually, yes. Some stuff with a long derivative history like the 737NG can still be found with steel.
I totally forgot about SDU! Of course, my question can be considered extended to that airport. The only advantage I see might be that the aircraft don't come in as steep as they do in LCY (5,5° angle) and that they have a wider runway available.
oldtimer From United Kingdom, joined Aug 2006, 191 posts, RR: 1 Reply 7, posted (2 years 3 weeks 3 days 17 hours ago) and read 3692 times:
Quoting Luftfahrer (Reply 6): I guess it would be a worthwhile investment for carriers based at LCY (read: BA CityFlyer) to have their aircraft equipped with carbon brakes.
BAe146/Avro RJ had carbon brakes from the early days, those that were doing stol landings were also fitted with brake fans, to assist with brake cooling for faster turnrounds
As a further point of interest, Concorde also had carbon brakes.
I assume the A318 and E190 would also have carbon brakes as they are better than steel for harsh application, being more efficient the hotter they get.
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