747-8 Test of Aborted Takeoff

[jollygreen07]

Extremely impressive. We actually talked about hot brakes situations today in sim ground day and it's really interesting to see a much much heavier jet really stomp on the brakes like that. We don't account for any thrust reverser usage when we run normal data, but they (the thrust reversers) really do add quite a bit of stopping power. Anyone who's flown on a commercial jet knows that.

 

[81montedriver]

What are assault landings? I think I might have done a few of those to some small boys.

Landings on a short unimproved strip ie what the Herc was designed to do. Anything less than 4000 ft is considered short field for us. Your approach speeds will typically be 10 kts less than normal approach speeds for 100% flaps. The speeds put you right above Vmca. As soon as you touchdown, power levers go to Max Reverse and use max brakes. Depending on your weight, you can stop in the range of 1500-2000 ft. Quite impressive for an aircraft so large.

For nighttime, repeat above, just add NVD's and a little more pucker factor

 

[81montedriver]

Extremely impressive. We actually talked about hot brakes situations today in sim ground day and it's really interesting to see a much much heavier jet really stomp on the brakes like that. We don't account for any thrust reverser usage when we run normal data, but they (the thrust reversers) really do add quite a bit of stopping power. Anyone who's flown on a commercial jet knows that.

I know you just said your stopping distance doesn't account for thrust reverser usage but how much would you guestimate it cuts down on your stopping distance?

 

[KBayDog]

The speeds put you right above Vmca.

They call him Adam Yauch, but he's MCA.

Seriously, the Herc can fit into some disgustingly tight spaces. Hell of an asset.

 

[statesman]

Electronic control. If HAL does not agree with it feathering or reversing, it don't.

Reliability. It flat out sucks.

No mechanical only failsafe. Imagine if your chute had a circuit board, that is more reliable on paper, but if it fails you are screwed and pulling harder won't help.

Blades erode in the rain. One flight in the rain can destroy the prop.

No proper testing in flight. Whirl rig only.

Shall I continue?

Sent via my HTC EVO 4G

Sounds like one of those situations where 99.9% of the time it's going to work great, but that 0.1% of the time it doesn't results in a mishap.

The electronic only Fx would make me uncomfortable, especially in a plane that has only two engines and a big drag disk on top.

 

[HAL Pilot]

If HAL does not agree with it feathering or reversing, it don't.

It depends if the pilot flying is or isn't a douche bag.....

 

[scoolbubba]

That's exactly what we are taught in Hercs. Although we have reverse thrust available, and you sure as hell use it when you are doing assault landings, BRAKES are what stop the airplane.

That sounds like the opposite of what we are taught. Reverse, reverse, reverse...brakes if you reaaaaalllyy NEED them below 120. Any "normal landing," most guys roll out without touching the brakes until they wanna slow down to get off the runway. Taxi the same way; I touch the brakes at the hold short, at the line up and wait, getting off the active, and pulling into chocks. Pretty much everything else is using reverse to maintain speed and slow down.

I guess that's a function of having 8k of smooth concrete, vice 3,999 feet of dirt.

 

[81montedriver]

That sounds like the opposite of what we are taught. Reverse, reverse, reverse...brakes if you reaaaaalllyy NEED them below 120. Any "normal landing," most guys roll out without touching the brakes until they wanna slow down to get off the runway. Taxi the same way; I touch the brakes at the hold short, at the line up and wait, getting off the active, and pulling into chocks. Pretty much everything else is using reverse to maintain speed and slow down.

I guess that's a function of having 8k of smooth concrete, vice 3,999 feet of dirt.

Right I was only talking about assault landings. When we are at home with an 8500ft runway, the power levers will come back, and we don't do anything until we get close to the end, at which point we will use reverse to slow us down and taxi. Brakes will only be used when coming to a complete stop.

 

[scoolbubba]

Right I was only talking about assault landings. When we are at home with an 8500ft runway, the power levers will come back, and we don't do anything until we get close to the end, at which point we will use reverse to slow us down and taxi. Brakes will only be used when coming to a complete stop.

Alright, that makes sense.

 

[Harrier Dude]

It's like a Billy Barou, but with a full twist at the end. Duh.

Don't you mean the Triple Lindy?

Billy Barou was a putter.

 

[MasterBates]

Billy Barou is also a bastardized SH 270 Overhead to a Small Deck.

 

[Harrier Dude]

Billy Barou is also a bastardized SH 270 Overhead to a Small Deck.

Aaaaahhhhhh......

I thought you mixed up your movie references.

 

[A4sForever]

The B747 (and I believe all transport category aircraft) are initially certified for a MGW stop just prior to V1 w/ brakes ONLY ... no reverse. They figure just what ARE you gonna' do if the reversers 'fail' or you have partial reverse deployment?? Thus the brakes only evolution ...

I've done it up to 833,000# (but prior to V1 and w/ serviceable brakes), and it's not something I'd like to do for practice ...

 

[MasterBates]

A4s (and other 18-wheeler drivers),

Is there any special braking technique for the MGW V1 Abort, or is it "mash on brakes, let anti skid do its magic, and NWS/Rudder/modulate brakes as needed to maintain centerline" sort of deal.

I've done a practice no-beta (no reverse or ground range pitch) abort in the Hummer, and it took damn near 5000 feet to stop from 15 kts short of V1, but I was going easy on brakes to not pop a tire.

 

[KBayDog]

Damn, I'm going to miss the Phrog.

Wheels touching down at 60kts, and coming to a complete stop prior to Spot 7...with no brakes.

F'ing priceless.