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Autobrake and Reversers


Joshua Akehurst

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@Joshua Akehurst

In most European destinations, the AIPs strictly prohibit the use of reverse thrust (other than idle) unless absolutely necessary for safety reasons. This is okay because most EU runways are long and landing distance calculations for aircraft certification purposes are usually predicated on the use of ground spoilers and brakes ONLY.

Autobrake setting is usually airline and pilot preference. There are very rare cases where the landing distance requires the use of a specific autobrake setting (usually abnormal procedures or contaminated runways).

For the 757/767, I usually set 2 for all runways and then click off the autobrake when I no longer want it engaged. Sometimes, I will even land with the autobrake off, especially if it is a long runway.

All takeoffs require the RTO (Rejected Takeoff) autobrake setting.

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On 5/23/2020 at 10:41 AM, Tiago G. (1019607) said:

The use of reverse is for most of the manufactors SOP, meaning after landing you must engage the REV at least at IDLE, otherwise you will have an event and you gonna be called to the office. AIPs and legislators can say and write what they want, because whatever they may write it can never be against safety. Other point to note is, looking into past events, we learn that some fatal crashes happened from overrun after REV being held at IDLE and not fully used. Why this happen? After so many years of using IDLE rev all the time, your muscle memory is used to IDLE rev and thats it. In the event you have an unexpected failure and need to act on the fly, you will be hostage of startle effect during which you will be using your muscle memory before you can think clearly. Unfortunatly, when things go south, everything happens very quickly.

So, the industry evolved, and now most of it recommends to, uppon landing, move the power to full reverse and in case you dont need it, bring it back to idle.

 

I chip in with my own knowledge here,  ( 12+years 737 ) - Standard is always idle reverse, nothing less nothing more. You would use anything more if you need it for brake cooling, landing performance  and/or in any non normal situation. Noise abatement procedures is only applicable under "good" conditions and in every other case you can justify the usage of 2nd detent or full reverse. 

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Hi Joshua,

The best way would be to "acquire" the software they use in real life to calculate autobrake setting however this is difficult to get and maybe not strictly legal. The next best thing is a landing performance calculator made for flight simulation use, for example TOPCAT. However these programs not always accurate and are not as detailed as the real deal. And finally the method most of us use is just to have a look at the runway length and set it to what we think will work.

As for reverser operations, that is usually chosen by the specific airline you are flying, for example British Airways use idle reverse as their standard procedure (no clue why, guessing to preserve the life of the engines) but this may vary between fights and airlines.

Simply put, use a landing performance calculator or your eyes to get autobrake setting and if you want reverser setting have a look at the operation for that specific airline.

Hope this helps,

-Sam

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It depends on multiple factors: landing weight, weather(wind, temperature, rain...), runway conditions(wet, dry), runway length(where you want to vacate runway, or full runway), airport altitude, airline...

If you are heavy, you need bigger force to stop you(air resistance from flaps, slats and air brake, brakes, thrust reversers), if you have tailwind, you will have bigger speed, again you need bigger force to stop in the same runway length. If runway is wet, traction is lower, so you will need to use alternative methods to slow down(thrust reversers, flaps, slats, air brake) because brakes won't produce force as big as on dry runway(you would need longer runway). On higher altitude airports you need higher approach speed to maintain lift, again bigger force needed. Also every airline can establish individual procedures. In some countries just as @Andrew H. sayed, it's prohibited to use reversers in case it isn't really needed for safe landing.

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On 5/8/2020 at 8:48 PM, Andrew (1021674) said:

@Andrew Heath

Most Norwegian airports have idle reversers allowed in the AIP, but that has never stopped pilots from going full reverse on most of the landings I've had. It's all down to weather and pilot's discretion up here.

The use of reverse is for most of the manufactors SOP, meaning after landing you must engage the REV at least at IDLE, otherwise you will have an event and you gonna be called to the office. AIPs and legislators can say and write what they want, because whatever they may write it can never be against safety. Other point to note is, looking into past events, we learn that some fatal crashes happened from overrun after REV being held at IDLE and not fully used. Why this happen? After so many years of using IDLE rev all the time, your muscle memory is used to IDLE rev and thats it. In the event you have an unexpected failure and need to act on the fly, you will be hostage of startle effect during which you will be using your muscle memory before you can think clearly. Unfortunatly, when things go south, everything happens very quickly.

So, the industry evolved, and now most of it recommends to, uppon landing, move the power to full reverse and in case you dont need it, bring it back to idle.

 

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