6:43 why would you turn off the elec pump before the engine is available to pressurise the hydraulic system? wouldn’t that just depressurise the system when you move the flight controls?
I think that because both pressure from elec pump on and eng 2 may overcharge the hyd system. And if you turn off the elec pump the ptu will work to pressurise the remaining hyd system
Great Video Captain. The virtual airline I fly for requires S/E taxi whenever possible and in the Toliss i had that poor PTU barking the whole way until I watched your video. Many thanks
New update for some weird reason doesnt allow single engine taxi in a manner that keeps the plane straight without having to give it rudder or tiller inputs.
just a quick one does the x bleed not act the place of the apu bleed reason i ask is if u have no apu bleed on u cant start engine but with x bleed on and apu bleed off the engine will still start
A very good question and the answer really is no. In the single engine taxi procedure, the crossbleed is only used to supply the packs during the taxi for passenger comfort. If you are operating for one of the numerous companies that taxi out with pack 2 off, you could just leave the crossbleed in auto. You always want to try and use the APU bleed for engine start if possible because it's powerful and supplies plenty of pressure at the start valve to get the engine rotating; bleed pressure from a running engine is not as powerful and sometimes requires you to increase the EPR/N1 on the running engine to supply sufficient pressure, which is not ideal.
My assumption is; if there is a strong headwind and you decide to do flight control checks, and if the IAS exceeds 72 knots, autobrake might arm itself during taxi due to spoiler extension. Im not sure if auto brake takes speed from GS or IAS. Im just having a silly guess, might have go try in the sim
Correct, auto brake logic depends on spoilers, that’s why after flight control checks, I wait for spoilers to retract and that is my trigger to arm the auto brakes and test takeoff config
My question is, if take off was rejected due to engine one failure, is the captain allowed to taxi in using engine two. If not plz explain why? Thks in advance.
You could technically do that in those circumstances, although if you rejected the takeoff the aircraft likely to be quite heavy and it may be that the captain were not happy to taxi single engine anyway, and may ask to be towed back to stand. In normal circumstances Engine 1 is used in conjunction with the Yellow Elec pump to avoid use of the PTU.
Nice video, how come after the 1st engine is started, the PTU doesn't 'bark' when a S/E taxi is being performed? See my video th-cam.com/video/2cX3cmKA67Q/w-d-xo.html&t (skip to 2:40). But it 'barks' after the first start on a normal taxi? The PTU is always switched on, correct? Cheers.
6:43 why would you turn off the elec pump before the engine is available to pressurise the hydraulic system? wouldn’t that just depressurise the system when you move the flight controls?
I think that because both pressure from elec pump on and eng 2 may overcharge the hyd system. And if you turn off the elec pump the ptu will work to pressurise the remaining hyd system
Great Video Captain. The virtual airline I fly for requires S/E taxi whenever possible and in the Toliss i had that poor PTU barking the whole way until I watched your video. Many thanks
New update for some weird reason doesnt allow single engine taxi in a manner that keeps the plane straight without having to give it rudder or tiller inputs.
just a quick one does the x bleed not act the place of the apu bleed reason i ask is if u have no apu bleed on u cant start engine but with x bleed on and apu bleed off the engine will still start
A very good question and the answer really is no. In the single engine taxi procedure, the crossbleed is only used to supply the packs during the taxi for passenger comfort. If you are operating for one of the numerous companies that taxi out with pack 2 off, you could just leave the crossbleed in auto. You always want to try and use the APU bleed for engine start if possible because it's powerful and supplies plenty of pressure at the start valve to get the engine rotating; bleed pressure from a running engine is not as powerful and sometimes requires you to increase the EPR/N1 on the running engine to supply sufficient pressure, which is not ideal.
@@flightsimguides8533 that now makes perfect sence and thank you for fast reply
Just a question how can I time when to start engine 2 that when it is avail and i have at least 2 minutes taxi before takeoff
Excellent video! So well explained. Thank you for making this.
Very well explained. Just one thing though. Flight control checks needs to be done BEFORE arming auto brake. Great video
Thank you, and you're quite right. Not quite sure why that is, but I've added another addendum in the comments section.
My assumption is; if there is a strong headwind and you decide to do flight control checks, and if the IAS exceeds 72 knots, autobrake might arm itself during taxi due to spoiler extension. Im not sure if auto brake takes speed from GS or IAS. Im just having a silly guess, might have go try in the sim
Correct, auto brake logic depends on spoilers, that’s why after flight control checks, I wait for spoilers to retract and that is my trigger to arm the auto brakes and test takeoff config
Noted...thanks for the tutorial...now I need one for the 737 lol
My question is, if take off was rejected due to engine one failure, is the captain allowed to taxi in using engine two. If not plz explain why?
Thks in advance.
You could technically do that in those circumstances, although if you rejected the takeoff the aircraft likely to be quite heavy and it may be that the captain were not happy to taxi single engine anyway, and may ask to be towed back to stand. In normal circumstances Engine 1 is used in conjunction with the Yellow Elec pump to avoid use of the PTU.
Great tutorial, Thanks
Nice video, how come after the 1st engine is started, the PTU doesn't 'bark' when a S/E taxi is being performed? See my video th-cam.com/video/2cX3cmKA67Q/w-d-xo.html&t (skip to 2:40). But it 'barks' after the first start on a normal taxi? The PTU is always switched on, correct? Cheers.
The PTU runs a 5 second self test during second engine start.
@@germantobon5498 but in the video I linked it runs without the 2nd engine being started. Is this to give hydraulic press to the brakes, steering ect?
I could perfectly hear how the yellow hydraulic system electric pump was turned off in order to test the PTU giving way to the star of engine number 2