Use of thrust reversers during taxi

[knobbygb]

I Watched a Ryanair 737-200 taxiing out to 06L at MAN today and twice during the (rather fast) taxi, he appeared to use the thrust reversers, presumabely to slow the aircraft. I've never seen that done before, so does anybody know if it's either a standard or non-standard procedure with Ryanair or anybody else?

The only reason I can imagine this MAY be done is to keep the brakes cool - it was a very fast taxi so I imagine they'd be used a lot - and it'd been a very short turnaround too. Is this close to the mark or not, or is it perhaps possible to accidently pull the thrust levers into reverse when going to idle? The distinctive 737-200 reverser buckets deployed for about 5 seconds on each occasion, but I couldn't hear if there was any increase in engine RPM.

[Bokomoko]

That procedure is operational for B737-200 series but it's recommended to keep reversers at idle or just a little above it. This really keeps brakes cooler but it doesn't mean that taxi speed can be faster than usual...

[Onan the Clumsy]

I've seen a bizjet taxiing this way once and I asked someone about it and he said it was standard to open just one bucket. That way they coiuld use one engine for going faster and one for slowing down.

[GlueBall]

In the USA some carriers at some airports "power-back" from the gate with reverse thrust.

[quid]

At my airline, use of reverse for taxi is at the Captain's discretion. Not permitted on the 767, though...too much chance of FOD damage

[icemanalgeria]

We operate 767 300 and in some airports we have a long taxi and hot temps plus the airport is at 2000ft amsl (Madrid) so on a clean wide taxi way I use idle reverse to save the brakes, we have brake temp readings and it does help.

However there are many places I would not use reverse on taxy ways because there is to much fod around.

[West Coast]

Reversers help out a lot if you have both (or more) running

[Sheep Guts]

I suppose from a propellor perspective. Ive used Reverse in a Twotter to back up gently. Its ok, aslong as you have a Marshaller or you know your clear behind. Also be carefull with the brakes when doing so. One can satnd on the breaks and put the ship on its "bum". With KIng Airs though and Twotter during taxi tend to use "Beta" and use reverse as an absolute last resort.

Allthough I have seen a Mexican PGR King Air B300 attempt a reverse into a Hangar once. Which incidently was not successfull. Also seen an Oz Army King Air B350 reverse at Darwin once aswell. This to me was not required as Tugs were freely available, and only causes possible F.O.D. problems and high ITTs.


Regards
Sheep

[knobbygb]

Thanks. Seems like it's done more than I thought. Guess it's just easier to spot on somthing like a 732. And there was me ready to slag-off Ryanair again.

[pilotwolf]

Check here too...

http://www.pprune.org/forums/showthread.php?s=&threadid=103759&perpage=15&pagenumber=1

[BAe 146-100]

Hi,

Picture of a Canadair CC-144B Challenger taxing with idle reverse at Madrid.

http://www.airliners.net/open.file/429379/M/

BAe 146-100

[Sle@per]

and only causes possible F.O.D. problems and high ITTs

can someone please enlighten me as to what both these abbrevs mean ..

FOD and ITTS ..

thanks

sleeper

[topcat450]

FOD - Foreign Object Damage
ITT - Internal Turbine Temperature

[7p3i7lot]

From a government report.

FAA certification experience consists of overtemperature testing at various governing temperature locations, such as Turbine Inlet Temperature (TIT),
Inter-turbine Temperature (ITT), or
Exhaust Gas Temperature (EGT).

ITT just means that the temperature is measured between turbine sections instead of in front (TIT) or at the end of the engine (EGT).

It seems that ITT is used primarily in turbo prop engines vice turbojets which use the EGT method. They all relate to the health or performance of the jet and are recorded by most operators to keep track of the wear and tear of the powerplant.
:cool:

[rwm]

ITT, EGT, TIT are all variations of basicaly the same measurement. All are measuring the engine temp, and each engine and or manufacturer has a prefered way to do this. It has little to do with turbo prop, turbo shaft, free turbine, reverse flow, turbo jet, turbo fan, ect. It mainly comes down to how the engine is designed.

This is as was stated a parameter measured for determination of the health of the engine. It is used in conjuction with a couple of other measurement such as N1, or Gas Producer, or Lp, and fuel flow, and torque, or thrust or EPR. Also needed is the density altitude and outside air temp.

Take a PT6T as in a Bell 212/412. You need to check the outside air temp, the altitude, you must pull 50% torque, and be at 97%rotor speed. From this you read a chart from the maintenace manual, or flight manual, and you will be given a ITT limit and an N1 limit. If your engine has numbers less than the limit in the chart, the engine is servicable.