Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

High thrust operation on A320

Tech Log The very best in practical technical discussion on the web

High thrust operation on A320

Old 28th Jan 2011, 10:39
  #1 (permalink)  
Thread Starter
 
Join Date: Apr 2004
Location: Europe
Posts: 87
High thrust operation on A320

As a fuel saving measure on the A320 (and all other a/c...) you can shut down the engine #2 during taxi-in.

Normally a 3 minute cool down period is considered before shutting down the engine. Books say that 3 minutes need to be considered after "high thrust operation". What is that?

Do we need to take 3 minutes, only after a landing where full reverse was used?
Or also after a landing with idle reverse? In this case the highest thrust has been on the ILS, in normal conditions around 45% N1.

Any idea?
Liftdumper is offline  
Old 28th Jan 2011, 11:01
  #2 (permalink)  
 
Join Date: Dec 2010
Location: asia
Age: 41
Posts: 1
If idle Rev was used for landing then you don't need to wait 3 min. Everything above idle rev requires 3min cooldown before shutdown.
Approach thrust on ils is not considered as high thrust.
That is by SOP.
It's of course somehow simplified as you can use rev thrust above idle but still less than approach thrust but then you need to cooldown for 3min.
Hope it clarifies
320cpt is offline  
Old 28th Jan 2011, 12:25
  #3 (permalink)  
 
Join Date: Feb 2005
Location: flyover country USA
Age: 77
Posts: 4,580
The OEM may have some guidance here. GE at one time suggested a EGT limit for the 3 minute rule.

Don't know if that's still in place.
barit1 is offline  
Old 28th Jan 2011, 13:04
  #4 (permalink)  
Moderator
 
Join Date: Apr 2004
Location: Rome
Posts: 761
For CFM engines Airbus has specified that the 3 minutes start when the engines are retarded to idle during landing provided idle reverse is used.
I-2021 is offline  
Old 28th Jan 2011, 15:52
  #5 (permalink)  

Only half a speed-brake
 
Join Date: Apr 2003
Location: Commuting home
Age: 41
Posts: 2,480
Good, it's been a topic here as well, though I believe we did not found the time to seek manufacturer's clarification. O-2021 would you share any "official" data?

Sincerely,
FD (the un-real)
FlightDetent is online now  
Old 28th Jan 2011, 16:05
  #6 (permalink)  
Moderator
 
Join Date: Apr 2004
Location: Rome
Posts: 761
Hey, of course. The thing is that we've got a communication from Airbus a few months ago because there was a lot of confusion on this topic also for the operator I used to work for. Since then I changed operator but I'll ask a mate to forward me that mail.
I-2021 is offline  
Old 28th Jan 2011, 21:38
  #7 (permalink)  
 
Join Date: Jun 2010
Location: On your right Skipper
Posts: 20
Our SOP is 3 mins cooldown regardless.

It could be a company thing rather than a manufacturer for us. 3-5 mins is about the required taxi time anyway for us to get to the gate in most airports that we operate.
pwned is offline  
Old 28th Jan 2011, 22:05
  #8 (permalink)  
Moderator
 
Join Date: Apr 2004
Location: Rome
Posts: 761
From Airbus

After landing, operate the engine at idle for 3 minutes before shutdown in order to thermally stabilize the hot section of the engine.
We consider hight thrust level operation to be thrust setting above REV IDLE or above normal taxi maneuvering power. Therefore, if MAX REV is used for landing, the three minutes cooldown period starts when reverse thrust is reduced to REV IDLE. *However, *if the landing is performed with idle reverse thrust or no reverse thrust, the cooldown period starts when the thrust is reduced at idle prior to touchdown.
During taxi, if the power level goes above the normal taxi maneuvering power, a cooldown has to be performed and the three minutes countdown starts when thrust is again at *( or near ) idle.

Cheers.
I-2021 is offline  
Old 28th Jan 2011, 22:15
  #9 (permalink)  
 
Join Date: Apr 2010
Location: in the flight deck
Posts: 89
if the power level goes above the normal taxi maneuvering power
how many %N1 is that ( or epr )?

Thanks .
Neupielot is offline  
Old 29th Jan 2011, 06:24
  #10 (permalink)  
Thread Starter
 
Join Date: Apr 2004
Location: Europe
Posts: 87
The max. N1 during taxi is 40%.
Liftdumper is offline  
Old 29th Jan 2011, 16:12
  #11 (permalink)  
 
Join Date: May 2005
Location: On a good day - at sea
Posts: 232
For a brief period of time (<2 yrs?, ?-2009) Airbus had a comment in the FCOM allowing a 1 min cooldown but they reverted back to 3 mins (after idle reverse) once GE saw in service results. Last time I spoke with our GE rep the recommendation re 1 min was only on an occassional basis for safety (crowded ramp) or exceptional operational reasons.
nnc0 is offline  
Old 11th Feb 2011, 20:56
  #12 (permalink)  
 
Join Date: Aug 2006
Location: London
Posts: 51
We operate CFM and IAE types. Our SOP is that no wait is required for idle on IAE as idle rev is not a high power setting for this engine. BUT idle rev is a high power setting on the CFM so 2 mins id required.
320 driver is offline  
Old 20th May 2019, 00:14
  #13 (permalink)  
 
Join Date: May 2019
Location: Planet Earth
Posts: 2
Max N1 Taxi

Originally Posted by Liftdumper View Post
The max. N1 during taxi is 40%.
Where can I find this exact limitation?
makmoco is offline  
Old 21st May 2019, 08:33
  #14 (permalink)  
 
Join Date: Mar 2012
Location: Having a margarita on the beach
Age: 100
Posts: 1,272
Originally Posted by makmoco View Post

Where can I find this exact limitation?
PRO-NOR-SOP

Little, if any, power above idle thrust will be needed to get the aircraft moving (40 % N1 maximum).Thrust should normally be used symmetrically. Once the aircraft starts to move, little thrust is required
sonicbum is online now  
Old 21st May 2019, 12:56
  #15 (permalink)  
 
Join Date: Dec 2010
Location: MC80 Home One type Star Cruiser
Posts: 146
FCOM PRO-NOR-SOP-22 for IAE Engines:

Note: The flight crew should operate the engines at or near idle thrust for a cooling period of 3 min before engine shutdown, in order to thermally stabilize the engines. Idle reverse thrust and normal thrust to maneuver during taxi (i.e. at or near idle), are not considered as high thrust operations. Therefore, both of the following applies:
‐ If the flight crew uses idle reverse thrust for landing and normal thrust to maneuver during taxi after landing, the cooling period starts when the flight crew retards the thrust lever during the flare
‐ If the flight crew uses maximum reverse for landing, the cooling period starts when the flight crew sets the thrust lever to idle reverse during the landing rollout.
However, if operationally necessary, all engines can be shut down when the aircraft arrives at the gate, regardless of the time necessary for landing. Before engine shutdown, routine cooling periods that last less than the recommended time, can result in engine degradation.


CFM and NEO have a different guidance. Check the applicable FCOM in PRO-NOR-SOP-22
Bus Driver Man is offline  
Old 21st May 2019, 13:49
  #16 (permalink)  
 
Join Date: Jul 2006
Location: Somewhere over the rainbow
Posts: 513
For the NEO with PW1100G engines, it's pretty much the same except they replaced the word '' should'' by '''must'' in the first sentence. And they removed that part too
[COLOR=left=#000000]However, if operationally necessary, all engines can be shut down when the aircraft arrives at the gate, regardless of the time necessary for landing. Before engine shutdown.[/COLOR]
Edit: Don't know what's wrong with my quote, it shows a color code xD.
pineteam is offline  
Old 21st May 2019, 22:43
  #17 (permalink)  
 
Join Date: May 2006
Location: FL510
Posts: 832
Our company had a visit from CFM, and their take was the optimum cool down time was 15 minutes.
Anything shorter eats into engine's life.
3 min is a bare minimum, any further minute helps increase engine life.
safelife is offline  
Old 21st May 2019, 22:46
  #18 (permalink)  
 
Join Date: Jul 2010
Location: Asia
Posts: 461
IAE engines used to define high thrust as greater than 1.02 EPR IIRC, EPR being their reference rather than N1. Coming to a stop during S/E taxi and having to get going again would usually result in this being exceeded, as would turning into a slightly uphill parking bay against the live engine or going over the fuel hydrant humps.

Seems to have disappeared from the FCOM now.
krismiler is offline  
Old 22nd May 2019, 07:15
  #19 (permalink)  
 
Join Date: Nov 2006
Location: Tropics
Posts: 305
It used to be worded that way in my FCOM as well, however that has changed since April 2017 in our FCOMs:

THRUST LEVER THRUST lever....................................................... ............................................................ .AS RQRD
The flight crew will need a little power above idle thrust to move the aircraft.
L2 For additional information on the thrust use during taxi, Refer to FCTM/PR-NP-SOP-100 Taxi Roll and Steering.
dream747 is offline  
Old 23rd May 2019, 00:01
  #20 (permalink)  

Only half a speed-brake
 
Join Date: Apr 2003
Location: Commuting home
Age: 41
Posts: 2,480
Originally Posted by safelife View Post
Our company had a visit from CFM, and their take was the optimum cool down time was 15 minutes.
Anything shorter eats into engine's life.
3 min is a bare minimum, any further minute helps increase engine life.
Was it the cooldown period? We had a visit from CFM too, where identical wording was used for to explain taxi out, engine warm-up thermal stabilisation.
FlightDetent is online now  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.