Single Engine Taxiing AND The Fuel Saving???

[AeroTech]

Run-up procedure during single taxiing?

Thank you for your posts.
I have some questions related to the single engine taxiing and the run-up engine procedure especially in congested airports.

-It seems the use of engine anti-ice during taxiing is not very efficient in certain icing situations like freezing drizzle. I am wondering if it is efficient why there is a need for run-up engine procedure during icing conditions?

-Is the fan and the nose spinner anti-iced (in the RECENT engines) when engine anti-ice is used or just the engine inlet is anti-iced?
All I know that in the JT8D the IGVs(inlet guide vanes) and the nose spinner are anti-iced (old engines)

- Is it possible to make run-up procedure while performing single or reduced engines taxiing?(the dead engine may accumulate more ice or may be pilots will alternate the use of engine during such taxiing?)

-Run-up engine of 70% N1 or more (even for 30 seconds or less) may present a hazard (jet blast) for the airplanes behind or even ground equipments?

Feedback appreciated. Thank you.
Best regards.

[junior_man]

You can't take off in freezing drizzle, only light freezing drizzle. You can taxi single engine in icing conditions. Main problem with engine icing is when it is running and sucking stuff in coupled with a pressure drop at the inlet.
After you get deiced you will start both up (if they weren't running) and take off shortly afterwards.
The CFM 56 only the fan cowl is heated by bleed air. The spinner is heated by engine oil and the fan blades are supposed to shed the ice (that is what the engine run is for). Most of the time the engine run 15 seconds is done in postition on the runway before takeoff so no jetblast problems and as long as it all looks good you just advance the power and go.

[747Flyer]

Originally Posted by RobertS975

As a frequent passenger on DL, I can tell you that DL taxis out on one engine on just about every twin I have been on- 737s, MD88s, 757s and 767s.

RobertS975 - DL began that in 1981 with the Iranian Oil Crisis. We taxied L-1011's and 727s on #2 only as well.

777 is difficult as it is designed to have both generators on the line, thus both engines...

[luc]

BA goes one step further

BA went one step further by flying back from america on 3 engines on a B747.
;-)

[hetfield]

Originally Posted by luc

BA went one step further by flying back from america on 3 engines on a B747.
;-)

APU running?

[junior_man]

I think that is their std ops. They did it a second time from SIN to LHR a week later.