Use of AutoBrakes & Guidelines (Delta especially)

[NC_BE300]

I was wondering if a notice was sent out to the pilots at Delta to use higher autobrake settings or something to that effect. The past few times I've been riding on DL, upon landing, more and more, I've noticed I'm being thrown on the lap belt alot more often.

Was also wondering what your OpsSpec guidelines were for the autobrake settings.

[Doug Taylor]

Probably depends on the aircraft, but there's really no specific guidance on autobrakes.

Knowing the MD-88's history with braking performance on wet/contaminated runways, I'll often use 'medium' when it's raining. But it turns out that it really wan't a braking problem as it was a problem with the autospoilers deploying during landing.

My thoughts are that if you run off a wet runway with the the autobrakes in the 'off' position', the inquiry committee is certainly going to ask you why you didn't use autobrakes.

[Jason]

Yeah I've noticed that as well on the couple dozen flights I've been on in the past few months - not just at DL but other airlines as well and usually in the mainline jets - the braking seems to be way more aggressive than ever even on dry runways during the day.....I mean I'm all for making the first highspeed but geez - they're going to have to start padding the BACK of the headrests before long.


Jason

[Doug Taylor]

Probably depends on the airport too. ATL likes to keep you fast until the marker and then you've got about 4 or 5 miles to dissipate about 60 knots, land in the touchdown zone and make the first or second high speed. If you miss the high speed turnoff, you're either going to get hit in the butt by six o'clock traffic or force a missed approach.

[MikeD]

[ QUOTE ]

My thoughts are that if you run off a wet runway with the the autobrakes in the 'off' position', the inquiry committee is certainly going to ask you why you didn't use autobrakes.

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Throw out the chute or drop the hook! [img]/ubbthreads/images/graemlins/grin.gif[/img]

[Doug Taylor]

All I have of that sort are aft airstairs!

[seagull]

The issue varies on several factors. Obviously, on a wet runway or low vis, autobrakes are a good idea to improve the safety margin. More even and positive application can help a lot. Absent these conditions, then the next factor is what kind of brakes you have. Carbon brakes and you still want to use the autobrakes. The brakes wear less on few applications, not on the length and amount of application (within reason). Steel brakes are a different animal, and you don't want to get them hot. In that case, it's better to not use the autobrakes, but rather slow the aircraft with a longer roll-out and reverse before any brake application.

The smaller jets all have steel brakes in my experience, as do the older aircraft. I would guess that the newer jets may have carbon, but you do need to know for sure. Some fleets are also mixed, so you have to know what you have.

[Doug Taylor]

Flying the -88 and the -90 on the same day was a challenge braking-wise.

On the -88, there's this sizeable 'dead zone' where you apply brakes and then you gradually begin experiencing braking action.

On the -90, it's like you lightly tap the pedal and then !!WHOMP!! you've got a spanky deceleration rate.

I'm not sure of what types of brakes are on either model.

[seagull]

The -90 sounds a bit more like the way carbon brakes act, but it could be related to other issues. Shouldn't be too hard to find out, I wouldn't think.

[Doug Taylor]

Yeah, sounds familiar!