Thrust Reversers Open During Taxi?

[PhilDernerJr]

Several of us at FLL yesterday noticed a few planes, epsecially G4's, taxiing to depart with their thrust reversers open.

We deduced that this was probably for the purpose of easing the stress on brakes when at idle. Is that the case?

Any other aircraft or airline (ever) do this?

[lijk604]

Several of us at FLL yesterday noticed a few planes, epsecially G4's, taxiing to depart with their thrust reversers open.

We deduced that this was probably for the purpose of easing the stress on brakes when at idle. Is that the case?

Any other aircraft or airline (ever) do this?

Phil,

That is exactly the reason. When the carbon brakes on the Gulfstreams cost as much as they do, owners will have the crew do anything to get a few more cycles on them. At the 2 biz-jet company's I have worked for, it is a standard practice. I don't think the airliners use them because they are not as efficient stopping 150,000 pound aircraft (during taxi) as they are a 50-75,000 pound bird. Here is a shot I took of one of my old birds at FRG doing exactly what you describe.

[airlinerstp://www.airliners.net/open.file/1089545/L/[/airliners

[LGA777]

Phil. we see this at LGA whenever they are departing 31, and the line taxies right by our Ramp Tower. And the most common (about 90 pct of the ones we see doing it) are G-4's, G-5's, and Global Express. In addition to I believe the accurate explanation from lijk604, another reason I believe is these planes are so overpowered they are constantly having to slow down during taxi, even at idle power, and that's a good thing.

Cheers

LGA777

[lijk604]

I believe is these planes are so overpowered they are constantly having to slow down during taxi, even at idle power, and that's a good thing.

Ron, you are absolutely correct, they are overpowered. You will also see Challenger 601, 604 & 300's also performing that type of braking. Not all Hawker's have TR's so that's why you don't always see it with them, and Citations are so slow as it is.

[adam613]

Yeah, I've seen that before...I remember thinking about it because the first time I saw it, I had just read a review in Flying of the G550, and he commented that the engines were so powerful at idle that you had to either ride the break or use reverse thrust when taxiing. But they can climb to FL410 in like 18 minutes, so it's worth it :)

[Alex T]

Phil--

Did you mean G4 as in the airline Allegiant or in reference to the GulfStreams?

I do know AA's MD80 do that also, though it has been rare when I saw it happen.

Though incidently, NWA DC9 back out on their own power using the reverser, lots of fun when that happens!

Alex

[PhilDernerJr]

I was referring to the Gulfstream.

I once saw an MD-80 powerback at LGA a few years ago.

[kc2aqg]

I once was onboard a NW DC-9 that powered back from the gate at DTW. It was awesome, but I would imagine it's not too common anymore with fuel the price it is.

[cancidas]

it's because the airplanes are light, and even at idle power there is so much thrust coming from the engines that the pilots would have to ride the brakes to keep it under control on the ground. it also helps to keep the ride nice and smooth for the pax onboard. that's the explanation i got from a G-V captain.

[nwafan20]

I once was onboard a NW DC-9 that powered back from the gate at DTW. It was awesome, but I would imagine it's not too common anymore with fuel the price it is.

Last time I was at DTW, they were still doing about 50% powerback.

[heeshung]

The first and only times I've seen aircraft powerback were at DTW. I still remember that it was a rainy day, and the thrust reversers blew a lot of rain onto the glass of the terminal.

[LGA777]

Eastern was real big on powerbacks at ATL, I once even got to poweback on an EA 757 ATL-SRQ, that was way cool.

LGA777

[hiss srq]

SRQ, woot woot woot! Are you sure that it was a 757? Ron, underwings are prohibited from powerback.

[LGA777]

SRQ, woot woot woot! Are you sure that it was a 757? Ron, underwings are prohibited from powerback.

Spellmen, not to be a di.k but it was in 1983 which means you where not even born yet so perhaps the rules have changed and yes I am very sure it was a 7 5 7 cause it said so on the tail !

[airlinerstp://www.airliners.net/open.file/0205212/L/[/airliners

LGA777

[hiss srq]

Okay................

[kc2aqg]

Just to bring this thought full-circle...the rationale of using thrust reversers at idle power instead of riding the brakes is to save wear and maintenance cost on carbon brakes which can be costly. What about the maintenance cost of the hydraulic actuators on the thrust reversers and other related engine parts? What about the increased risk of foreign object debris ingestion? Correct me if I am wrong, is what's being said here is that the maintenance cost of brakes is still more than the cost of maintaining an engine / thrust reverser assembly?