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Reversers On Taxiway  
User currently offlinejodoloy From United States of America, joined Oct 2011, 22 posts, RR: 0
Posted (1 year 3 months 5 days 10 hours ago) and read 9904 times:

The other day as I was doing my Pre-flight, I noticed an Allegiant MD-80 using its reversers to slow down on the taxiway. I have never noticed this before. Is this something unique, or does it occur everyday?

38 replies: All unread, showing first 25:
 
User currently offlinelonghauler From Canada, joined Mar 2004, 4758 posts, RR: 43
Reply 1, posted (1 year 3 months 5 days 9 hours ago) and read 9902 times:

I used to do it on the B737-200. The idle thrust of the -17 engines was pretty high, it was an effective way to keep the brakes cool.

In fact, when the airplane was light, I used to taxi with one in idle reverse, it kept the speed slow. You have no idea how many times the airplane behind us warned us that we might not know one was in reverse.



Never gonna grow up, never gonna slow down .... Barefoot Blue Jean Night
User currently offlineGoBoeing From United States of America, joined Jun 2000, 2679 posts, RR: 14
Reply 2, posted (1 year 3 months 5 days 2 hours ago) and read 9736 times:

On the ERJ-135/145 series, a technique was to not just use the reverse thrust to prevent the brakes from heating up, but to actually cool the brakes. The airflow when the buckets are deployed would conveniently blast down on the brakes and cool them off a little. Saw a captain do this once or twice following a quick turn while the brakes were still hot from the arrival as we taxiied out for departure.

User currently offlineN243NW From United States of America, joined Jul 2003, 1609 posts, RR: 20
Reply 3, posted (1 year 3 months 5 days ago) and read 9702 times:

Quoting longhauler (Reply 1):
You have no idea how many times the airplane behind us warned us that we might not know one was in reverse.

Gotta love unsolicited "advice" from other pilots. One of our MD-80s rejected takeoff at more than 100 knots the other week when a nearby pilot reported that the plane had a piece of FOD attached to the nose gear.

It was the spray deflector.  



B-52s don't take off. They scare the ground away.
User currently offlineHAWK21M From India, joined Jan 2001, 31568 posts, RR: 57
Reply 4, posted (1 year 3 months 5 days ago) and read 9660 times:

Some Airlines have issued SOPs to their Flight crew to reduce brake usage to save on the brake overhaul frequency.
This is to use the full length of the runway post touchdown & minimum use of brakes.in such cases one might see the T/Rs being used instead.



Think of the brighter side!
User currently offlineatct From United States of America, joined Mar 2001, 2223 posts, RR: 39
Reply 5, posted (1 year 3 months 4 days 23 hours ago) and read 9648 times:

In the King Air / MU2 we would use beta frequently while taxiing as at idle she'll scoot pretty quick down the taxiway. My buddy flies Lear 60's and GV's and they frequently taxi with one bucket open at idle thrust. The other engine at idle provides the perfect amount of thrust for a nice, steady taxi.

atct



"The way to get started is to quit talking and begin doing." - Walt Disney
User currently offlineTristarsteve From Sweden, joined Nov 2005, 3930 posts, RR: 34
Reply 6, posted (1 year 3 months 4 days 14 hours ago) and read 9520 times:

Quoting HAWK21M (Reply 4):
Some Airlines have issued SOPs to their Flight crew to reduce brake usage to save on the brake overhaul frequency.
This is to use the full length of the runway post touchdown & minimum use of brakes.in such cases one might see the T/Rs being used instead.

Yes, the airframe guys get onto Flt Ops about brake usage and get the Engines used for slowing down.
A year later the engine guys notice and make a case to Flt Ops to get it reversed.
And so it goes on.
Brakes are cheaper than engines!


User currently offlinem1m2 From Canada, joined Dec 2011, 79 posts, RR: 0
Reply 7, posted (1 year 3 months 4 days 12 hours ago) and read 9457 times:

The Dash 8 also likes to taxi way too fast if the props are in flight idle. I use beta while taxiing. The CRJ 100/200 also likes to taxi rather rapidly if one thrust reverser isn't opened.

User currently offlineAA737-823 From United States of America, joined Mar 2000, 5637 posts, RR: 11
Reply 8, posted (1 year 3 months 4 days 8 hours ago) and read 9343 times:

The F-100 aircraft do this frequently as well (and, I assume, F-70s). Those Tays make a good bit of push on the small airframe.
For maintenance on 737-200s, I sometimes do it during taxi, as we're taxying an empty airplane, and it'll build up speed, even on an uphill taxiway. Otherwise, you're forced to apply brakes, release them, apply them, release them, and so on, which is uncomfortable and awkward. The brakes on a -200 aren't very..... linear. They're more like ON or OFF!!!

Quoting Tristarsteve (Reply 6):
Brakes are cheaper than engines!

But at idle reverse, it's a moot point. Idle is idle.

Quoting atct (Reply 5):
My buddy flies Lear 60's and GV's and they frequently taxi with one bucket open at idle thrust.

I've noticed that quite a lot, in multiple bizjet types.


User currently offlineglen From Switzerland, joined Jun 2005, 211 posts, RR: 2
Reply 9, posted (1 year 3 months 3 days 23 hours ago) and read 9213 times:

Quoting AA737-823 (Reply 8):
But at idle reverse, it's a moot point. Idle is idle.

But reverse at low speed increases the risk of FOD.



"The horizon of many people is a circle with zero radius which they call their point of view." - Albert Einstein
User currently offlinetb727 From United States of America, joined Jun 2005, 1546 posts, RR: 8
Reply 10, posted (1 year 3 months 3 days 14 hours ago) and read 9091 times:

Quoting glen (Reply 9):
But reverse at low speed increases the risk of FOD.

Which is true. In the Lear 25 we could only pop them on taxi during the first flight of the day for the TR check and we would make it quick. When you did it, even at idle, you would sometimes see dust fly up almost to the nose of the plane if you were looking outside!

The only engine we are allowed to intentionally reverse on the ground is the #2 engine on the 727 because the thrust is diverted to the sides instead of up and down like the pods. A popular thing to do after landing and cool down is to kill #2 (some guys call it OJ'ing it, twisted I know). This is my first winter taxiing the 727 so I prefer to keep #2 running in case I need to pop it if it's icy or I need to slow down so I tend to cage #3 if I am going to shut one down.

When we have a large load of horses on board to keep the cool air flowing from the packs it is also possible to push #1&3 up a little and pop #2 while taxiing on a really hot day. That way we keep the temperature in the cabin under control and we don't drag the brakes while trying not to hit SWA taxi speeds 



Too lazy to work, too scared to steal!
User currently offlineIAHFLYR From United States of America, joined Jun 2005, 4790 posts, RR: 23
Reply 11, posted (1 year 3 months 3 days 6 hours ago) and read 8937 times:

Quoting N243NW (Reply 3):
It was the spray deflector.


   yep gotta love the help....glad it wasn't serious though.

Years back I heard some Gulfstream pilot tell the ground controller when they were asked about a reverser being deployed during taxi , "its deployed to keep the wind from blowing out the fire in the engine" as they motored downwind on the taxiway during the strong north wind. Not sure about that one but guess it could be...............    I'm not sure the controller is right to this day.



Any views shared are strictly my own and do not a represent those of any former employer.
User currently offlineAA737-823 From United States of America, joined Mar 2000, 5637 posts, RR: 11
Reply 12, posted (1 year 3 months 3 days 6 hours ago) and read 8927 times:

Quoting glen (Reply 9):
But reverse at low speed increases the risk of FOD.

Yeah, but don't tell KLM that, as I've found a photo to back up what I said earlier about it on the Fokkers:

View Large View Medium
Click here for bigger photo!

Photo © Tomas Lauer

Quoting IAHFLYR (Reply 11):
"its deployed to keep the wind from blowing out the fire in the engine" as they motored downwind on the taxiway during the strong north wind. Not sure about that one but guess it could be...............  

Some engines, believe it or not, are actually pretty sensitive to tailwinds. Even the mighty CFM56 has it's limits.


User currently offlineHAWK21M From India, joined Jan 2001, 31568 posts, RR: 57
Reply 13, posted (1 year 3 months 2 days 17 hours ago) and read 8786 times:

Quoting Tristarsteve (Reply 6):
Yes, the airframe guys get onto Flt Ops about brake usage and get the Engines used for slowing down.
A year later the engine guys notice and make a case to Flt Ops to get it reversed.
And so it goes on.
Brakes are cheaper than engines!

What transpires if one is Airframe & Engine qualified  

On a serious note.... whats the case for Engine damage if RT is used for slowing down.



Think of the brighter side!
User currently offlinem1m2 From Canada, joined Dec 2011, 79 posts, RR: 0
Reply 14, posted (1 year 3 months 2 days 8 hours ago) and read 8681 times:

Just that it's work that can be done by the brakes rather than adding extra wear to the engines and burning more fuel. I think that's what you are asking about?

Using them at slow speeds has the potential to blow debris into the air in front of the engine which can subsequently be ingested by the engine. We all know what this would do.


User currently offlinelonghauler From Canada, joined Mar 2004, 4758 posts, RR: 43
Reply 15, posted (1 year 3 months 2 days 7 hours ago) and read 8659 times:

Quoting m1m2 (Reply 14):
Just that it's work that can be done by the brakes rather than adding extra wear to the engines and burning more fuel. I think that's what you are asking about?

Normally when taxiing, nothing more than idle reverse is used. This is used less to slow down, than more to harness the excess thrust. Being at idle, no extra fuel is burned than if the engine remained in forward thrust. Also, brake temperature is often an issue when taxiing out, idle reverse can control that.

Quoting m1m2 (Reply 14):
Using them at slow speeds has the potential to blow debris into the air in front of the engine which can subsequently be ingested by the engine. We all know what this would do.

Most B737-200s, (and DC-9s) have the reverser buckets rotated out of centre line. This puts the area of thrust ground contact outside of the engine intake, instead of directly under it. While not entirely effective, this does reduce FOD ingestion.

For example:


View Large View Medium
Click here for bigger photo!

Photo © Andrés Contador - AirTeamImages




Never gonna grow up, never gonna slow down .... Barefoot Blue Jean Night
User currently offlinefreeze3192 From United States of America, joined Oct 2006, 164 posts, RR: 0
Reply 16, posted (1 year 3 months 2 days 4 hours ago) and read 8616 times:

Popping a reverser during taxi is (or was last time I checked) an approved procedure for the ERJ side of XJT.


"A passenger bets his life that his pilot is a worthy heir to an ancient tradition of excellence and professionalism."
User currently offlineGlobalMoose From United States of America, joined Aug 2012, 25 posts, RR: 0
Reply 17, posted (1 year 3 months 1 day 4 hours ago) and read 8497 times:

We throw out the TRs all of the time while taxiing. We generally put them out on 2 & 3 to help balance the forward thrust from 1 & 4 when we are at lighter weights. It gets really annoying to have to either ride the brakes (not recommended) or constantly speeding up and slowing down...

Other times, when we are really heavy, I'll use all four in reverse idle to help slow down as required (at 20 kts or so and taxiing along a downslope). A large part of our TOLD is based upon brake temps (two speeds are given on takeoff and landing - one where if we get on the brakes above a given speed, the fuse plugs melt and another, higher speed that is the maximum energy absorption capability of the brakes).

I'll try and keep the brakes under 50 C - it is amazing how much the temps can rise when you are taxing a 500,000 lb aircraft around a large airport!



When it absolutely positively has to be there ... at some point.
User currently offlineAA737-823 From United States of America, joined Mar 2000, 5637 posts, RR: 11
Reply 18, posted (1 year 3 months 8 hours ago) and read 8362 times:

Quoting GlobalMoose (Reply 17):
We

Who?

Quoting GlobalMoose (Reply 17):
throw out the TRs all of the time while taxiing.

While taxying what? I gather a four-engined aircraft... more specifically?
You say 500k.... I've certainly never seen a 747 taxi around with #2 and #3 in reverse, and given the translating cowl-style reverser, those engines are particularly prone to FOD damage while in reverse, so I'm having a hard time with that policy at your company!

Quoting longhauler (Reply 15):
Being at idle, no extra fuel is burned than if the engine remained in forward thrust.

Just to pick at nits (and to provide bemusing anecdotal information), a JT8-D is prone to stall if left at idle in reverse; consequently, when you enter Detent 1 on the reverser handle, the FCU spools the engine up JUST a hair, to provide a little more motivation to get the exhaust out of the tailpipe!
Engines that reverse only the bypass flow are obviously not prone to this issue, as the core can still breathe just fine in reverse.


User currently offlinelonghauler From Canada, joined Mar 2004, 4758 posts, RR: 43
Reply 19, posted (1 year 3 months 8 hours ago) and read 8358 times:

Quoting AA737-823 (Reply 18):
Just to pick at nits (and to provide bemusing anecdotal information), a JT8-D is prone to stall if left at idle in reverse; consequently, when you enter Detent 1 on the reverser handle, the FCU spools the engine up JUST a hair, to provide a little more motivation to get the exhaust out of the tailpipe!

I never noticed that! And ... I have over 5000 hours on the B737-200. (as I always say, its a bad day you don't learn something!) Is that all of them? As I noticed that the idle is quite a bit higher on the -15, or -17, over the -9s. So I never taxied with the -9s in reverse, just the -17s.

Quoting AA737-823 (Reply 18):
Engines that reverse only the bypass flow are obviously not prone to this issue, as the core can still breathe just fine in reverse.

Yes, but usually those engines have a minimum recommended airspeed for reverse. The airplane I fly now, recommends 70 knots minimum for max reverse, and 50 knots for idle reverse. That being said though, an F/O recently asked why my hand was on the reverse levers as we entered the gate area, "you just never know" I replied, "you never know"!



Never gonna grow up, never gonna slow down .... Barefoot Blue Jean Night
User currently offlineGlobalMoose From United States of America, joined Aug 2012, 25 posts, RR: 0
Reply 20, posted (1 year 3 months 2 hours ago) and read 8296 times:

Quoting AA737-823 (Reply 18):

C-17A.



When it absolutely positively has to be there ... at some point.
User currently offlineYikes! From Canada, joined Oct 2001, 284 posts, RR: 1
Reply 21, posted (1 year 2 months 3 weeks 5 days 3 hours ago) and read 8052 times:

I have been away from this forum for a number of years.

I used idle reverse on the 763 while taxiing in after landing many, many times but never while taxiing out for takeoff. It was a very effective and safe method to control taxi speeds on an aircraft that was typically light weight at destination.


User currently offlineAA737-823 From United States of America, joined Mar 2000, 5637 posts, RR: 11
Reply 22, posted (1 year 2 months 3 weeks 3 days 19 hours ago) and read 7918 times:

Quoting longhauler (Reply 19):
I never noticed that! And ... I have over 5000 hours on the B737-200. (as I always say, its a bad day you don't learn something!) Is that all of them? As I noticed that the idle is quite a bit higher on the -15, or -17, over the -9s. So I never taxied with the -9s in reverse, just the -17s.

It's very subtle; we mechs have to be watching the EPR and N2 gages closely; my ear is pretty good, but the increase in fan noise is drowned out by the scream of the diverted airflow!
As to whether it's all of them, I can only testify to the -17A.

Quoting longhauler (Reply 19):
That being said though, an F/O recently asked why my hand was on the reverse levers as we entered the gate area, "you just never know" I replied, "you never know"!

Indeed; here in slick, slick, slick Anchorage, I've watched pilots taxi into position (and also at the hangar) using differential reverse thrust to steer the airplane. You'll see the nosewheel turn a bit, then a bit more, then FULL deflection with no effect on aircraft heading... that's when you put your hood up over your head, because you know that the inboard engine is about to go into reverse!

Quoting GlobalMoose (Reply 20):
C-17A.

Aah, a truly unique airframe indeed! And, with high-mount engines, you have a LOT of freedoms that FOD suckers don't enjoy.


User currently offlinewoodreau From United States of America, joined Sep 2001, 978 posts, RR: 6
Reply 23, posted (1 year 2 months 3 weeks 3 days 16 hours ago) and read 7905 times:

Quoting freeze3192 (Reply 16):
Popping a reverser during taxi is (or was last time I checked) an approved procedure for the ERJ side of XJT.

At least someone is sane. Thrust reverser use at another American major ERJ-145 operator is prohibited when landing on dry runways, for taxi, and a whole lot of other reasons - basically you're not allowed to use them at all - all to save on maintenance costs related to maintaining thrust reversers. The only time the thrust reversers are allowed to be used is to prevent a runway excursion, as a last ditch method to keep from going past the end of the runway- which doesn't make a whole lot of sense as you know reversers work better at high speeds, brakes better at low speeds.



Bonus animus sit, ab experientia. Quod salvatum fuerit de malis usu venit judicium.
User currently offlineHAWK21M From India, joined Jan 2001, 31568 posts, RR: 57
Reply 24, posted (1 year 2 months 3 weeks 23 hours ago) and read 7720 times:

Quoting woodreau (Reply 23):

Wouldn't a circular be accompanied by the reasoning too.



Think of the brighter side!
25 jetstar : On the Lockheed JetStar, for the first flight of the day we would deploy and test the reversers during taxi, it was part of our taxi checklist. If we
26 DashTrash : I used to do it in the Citation X. We weren't allowed to single engine taxi and both motors going is just too much push even at idle when the airplane
27 Kaiarahi : Would that be the operator that's twice overrun 07 at YOW?
28 Post contains links Roseflyer : On airplanes with carbon fiber brakes (MD80 isn’t one of them), braking at taxi speed actually causes more wear to the brakes than landing. The reas
29 N353SK : No ... the airline you're thinking of is so cheap that some of their ERJs aren't even equipped with thrust reversers.
30 airportugal310 : UAX right?
31 N353SK : Yes.. Trans States
32 FlyboyOz : Didn't a 737-200 use reversers all the time after touching down on the runway?
33 HAWK21M : Unless you have one INOP & Deffered under MEL. Also depends on the Runway length.
34 slimshady : C-17 is different than airliners with regard to thrust reverse.. Clamshell reversers on planes like the MD-80 deflect ALL thrust. Translating sleeves
35 Acey559 : We can't do it at Eagle, our limitations prohibit reverser use during taxi except for emergencies.
36 HAWK21M : Why is it not decibal restricted rather than non use of TRs, some Aircraft would be less noisy than others.
37 evil8er2006 : When I flew C-17s, I rarely taxied with 2 & 3 in Idle Rev and I rarely flew with folks who did. Yes, I used the brakes a little more, but I felt
38 mhkansan : Some of the ex-ATR pilots at Eagle do it all the time. Some guys use the TR to corner better, some don't touch it and burn up the whole runway on lan
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