Damn all these time we pilots always thought Recirc ON + HIGH flow would make the cabin cool fast. Never knew we need to turn off Recirc until now. That's probably the reason why we turn on the Recircs because want more air flowing down our sweaty faces. Thank you so much for this hack.
I am currently studying my ATR 72 type rating, in particular the whole system with books and docs. It's quite complex and not easy to understand most of the time until I watch your videos. Many thanks Captain!!
The same can apply to our cars, they also have recirculating valves and the manuals also recommend not recirculating if you have just entered the vehicle which was parked under scorching sun.
Hello Magnar. I just wanted to thank you for all of your videos. They have been extremely helpful for a relatively experienced pilot switching over to the ATR from the Saab 340. Although similar, the systems on the ATR are unique and your explanations are so clear and helpful Thanks again - from Canada!
Great series of videos. This may be intended for pilots, but as a tech I find it very informative, and indispensable for troubleshooting the aircraft. Much better than my GenFam courses. Thank you for sharing your knowledge and experiences with us all.
Thank you once again Captain for a great video with a lot of good and vibrant explanations. There are definitely always new things to learn about this bird. cheers from Denmark /Thomas
Captain, thank you for such an informative video and explanation. I should be grateful if you could pass this along to ALL Wings Air (PT. Wings Abadi Airlines) pilots who seemingly do no know how to activate the pax aircon. They seemingly leave it INOP until well established on climb, just prior to cruise. No doubt they know how to operate the system for the flight deck!
Great work captain. Very well explaination of the systems for some one who wants to learn or refresh his knowledges. Also far more interesting than most of hypnotic WBTs
Thank you Captain Magnar for this detailed explanation, really an eye opener for myself. I've experienced a few times while trying to cool the cabin, On hotel mode with HI flow & PL to the gust lock stop, after a few minutes it will trigger Bleed #2 Leak and therefore pack #2 fault. Would really appreciate your thoughts on as to why that may happen..even though the procedure is stated in the manual Im operating in Malaysia where the OAT is about 25-34 celcius.
A bleed leak alert will close the bleed valve and the pack valve. I have not experienced this, even when it's 35 degrees. But a bleed leak alert must not be reset; the indication must be investigated by maintenance.
Thanks captain magnar, but I didn't notice clearly the reason of turning off the the recirculation fans when it is needed to bring the temperature down
Hello, Captain. What should be done for dual bleed failure? Since bleed air is necessary for cabin pressurization, would an emergency descent be necessary when cruising at higher altitudes to prevent gradual decompression, or should only PACK VALVE 1+2 FAULT checklist be followed?
The cabin pressure will decline gradually, so an emergency descent is not required. Just follow the checklist for PACK 1+2 VALVES FAULT and descent to FL100 or MEA.
Oh, thanks. I was wondering what that is because it is on the schematic in my airline’s manual. But not mentioned at all. (I haven’t had a chance to look in the ATR manuals yet.)
Hello Capt, Season Greetings to you Very glad to see you in this, wonderful videos and your simplified version of the systems makes it more easier and interesting to understand this complex airplane. Keep doing more ! P. s u did my check in Bangkok sometime in 2015 and it was a great Memory ..
Hello captain , as pilot in ATR 72 500 i really enjoy and i learning more and more from You sir , is There any possibility to make for us a vidéo about power plant thank you captain .
Thank you for informative video. Have doubt about regarding rotary knob for temp control. When there is auto temp mode is given then what is use of this rotary knob to control the temp. It is understood when it is in manual mode rotary knob is required to control the temp but when it is an auto mode will that rotary knob make any difference. Kindly explain
In automatic mode, the temperature control knob is used to set the temperature in the cabin/cockpit. In manual mode, the temperature control knob is used to operate the temperature control valve directly. See FCOM DSC.21.2 page 20.
Hello Capt. Magnar, i have a question to ask. On the QRH, if both packs failed, it is said that the max flight time is limited to 80 minutes. is there any specific reason/reference to the limited flight time? thank you very much.
CO2. When both air conditioning packs have failed, cabin air is not replenished with fresh air. This causes the CO2 concentration to increase. With a cabin full of passengers, the 80 minute limitation will limit the CO2 concentration to a maximum of 3%. This is regarded to be safe by EASA.
Please Magnar, could you explain why we don't turn, let's say, the bleed #1 off when we are flying with pack#1 off (inop)? At least the checklist doesn't mention it. Thank you.
Because the associated engine bleed valve has not failed. Let's say pack #1 has failed. When you taxi in, you will normally shut down engine #2 after to minutes. Bleed #1 will then supply pack #2 via the crossfeed valve.
Unfortunately, an FCOM is the property of ATR or the owner of the aircraft. The FCOM is customized to the equipment installed in a specific aircraft. Therefore, you will not find FCOM online that can be legally downloaded.
Hello :) Manuel mod- full hot position duck temperature does not exceed 50 degrees in switch flight cmpt. mode and hot by-pass valve does not open. Temp cont valve open. Where is the problem?
Hello Captain, thank you for your videos. On this one, i have a question, related to the mixing chamber. You said that in case of fail of one pack, the mixing chamber supplied the other side. That was what i though also, but a few months ago, with this doubt, a mechanic show me the schematic, and there is one mixing chamber per pack, isolated. Meaning that doesnt have any connection to suplly the other side. Can i please ask you to clarify this? Thank you and best regards
It depends how you define "mixing chamber." The mixing chamber I was talking about, is a duct between the pack outlets. It is visible when you remove the floor panels.
Thank you for your answer. That make me a litlle bit more confused. I was talking about the mixing chamber after the packs. I though there was a single mixing chamber for the 2 packs, as show on cbts and fcom, but i´ve been show that each pack as a mixing chamber, and they do not feed air to the other side or pack, thats why now im a litlle bit confused again.
@@ricardoamado3672, ther mixing chamber is after the packs. If you have other drawings, please share them with me. You will find my email address on my profile.
Air Conditioning on a ATR. Uh huh. Vague to almost non existant-better on the "large"-think PW 127 engines. The 120 engines-ugh. On an airframe that sold large numbers to operators near the Equator. 15 years as a lead heavy MX mech with a FedEx feeder-also dealt with MANY airframes coming out of Central & South America as well as Oceania. Toulouse could learn a few things from Boeing on that subject...... The Cabin Smoke Abatement mod did do wonders-but ya better have your David Clarks on real good.
Hello Captain, thank you for such an informative video. When the airspeed is below 150 kt and retracted for less than 10 mins., the turbo Shutoff Valve opens. What is the significance of that 10 mins limitation?
Temperature is one of several factors affecting maximum payload. I have listed them in this video about tale-off performance: th-cam.com/video/AIfwMy-rhig/w-d-xo.html
captain can you please let me know what source are you using for those panel images to demonstrate for us? (cockpit panel ) or if you can introduce me to a source/ i found one original ATR72-500 belongs to company but not clear . iappreciate
@@FlywithMagnar thank you sir for reply. those beautiful images from cockpit parts drawn by yourself??? imazing. would it be possible to have the overpanel and main and radio panels images?? IF IF it is ok with you. otherwise understandable..
@@FlywithMagnar thank you captain i absolutely understand. thank you for great videos . i hope you post more and more specially about dark and cold start up
That depends on the aircraft type. In ATR aircraft, the pressurization is controlled by a computer and provides a smooth change in cabin air pressure as we climb and descend. If we use manual override, we should be able to maintain sea level air pressure when flying up to 13,800 ft.
Hello Magnar, I am bit puzzled about ENG1 BLEED valve close logic during Hotel Mode. Do you know what is the reason for ENG1 BLEED valve to be closed when prop brake is engaged? Thank you.
Thank you for pointing out this. When I made the video, I used the latest FCOM revision. Unfortunately, the manufacturer made an error here. The last line should not be there. FCOM revisions pre-dating the EDORA (Electronic Documentation for Regional Aircraft) system are correct. Edit: I was too quick to draw this conclusion. Please read the responses below.
@@FlywithMagnar Thank you for reply. I did checked several of my FCOM dated between DEC 1997 and JAN 2018 and all actually state same information: "The bleed air shutoff valve automatically closes in the following cases: ..... PROPELLER BRAKE selected ON (for only left bleed valve)" So now I am puzzled even more. :-) Is this real behavior? Anyone able to observe this in aircraft? I know that it is not usual aircraft state, as typically when you have ENG2 in Hotel Mode (prop brake engage) you don't have ENG1 running. And standard procedure is to release prop brake before starting ENG1. Maybe @mzo could tell us? ;-)
This is getting more and more mysterious. I have FCOM for AT43, AT45, AT72, AT75 (3 revisions), and AT76 (3 revisions). All of them, with the exemption of one, says "The bleed air shutoff valve automatically closes in the following cases: ..... PROPELLER BRAKE selected ON (for only left bleed valve). The 2011 revision of AT76 FCOM does not have this line. I have done a lot of starts where the propeller brake was ON and we started engine #1 first. During the start, bleed #1 was OFF. It was selected ON after the start and opened immediately. You can see it at 11 minutes in this video: th-cam.com/video/sF8q8bcR8TU/w-d-xo.html FCOM says "PROPELLER BRAKE selected ON". This might be interpreted in the following way: Bleed valve #1 closes when we SELECT the propeller brake ON.
@@FlywithMagnar My FCOM are for AT45, AT75 and AT72 and I can confirm what you found - all state same. Also in your great video, it is clearly visible, that you can have ENG1 Bleed ON with Prop Brake ON. Do you mean that Bleed will close during Prop Brake engage procedure? And open again when Prop Brake is engaged? That is rather mysterious. Even more as I do not see reason for ENG1 Bleed to be OFF during Prop Brake engagement or even when Prop Brake is ON. Someone having any idea? ;-) To add even more puzzles: in your video 11:24 - ENG1 Starter ON, around 11:45 ENG1 NH Stabilized and 11:50 ENG1 Bleed ON. This means that between begin of the start procedure and Bleed ON is less than 30sec. My FCOM says: During a starting sequence, the opening of the bleed air shutoff valve is inhibited. You mentioned in the video, that it is inhibited for 30sec. But it seems to be less. I can try to dig through Maintenance Manual, but I would expect Bleed opening to be delayed as function of NH and controlled by MFC, not by timer. But I was so many times wrong when tried to guess supposed ATR systems functions... :-) By the way another interesting question. As HP air for deicing is not going through Bleed valve, but directly Deice Valve, so I would guess that Deice valve opening should be delayed as well during engine startup, to avoid potential hot start. But surprisingly nothing about that mentioned in FCOM. I would expect same logic to be applied for Deice Valve as for Bleed Valve during ENG start. This would cause AFR AIR BLEED and 1 ENG 2 annunciators on deice panel to cope with status of the Bleed valve. Or I am completely wrong?
Digging through Maintenance Manual Chapter 36: - During the engine starting the bleed air shut-off valve opening is inhibited an consequently the system goes to off. The valve will not open until 30sec after 45% NH engine has been attained. Is Maintenance Manual wrong about blocking opening of Bleed valve until 30 sec after 45% HN? Well I don't think so. MFC only seem to block normal Bleed valve annunciation (you should get FAULT when valve position disagreed with selected position). You can see Pack valve being Fault when Bleed is selected ON (at 11:49). This is due to no pressure available from Bleed1. And around 12:11 you can barely but see crossfeed valve opening (as Bleed1 finally delivers air pressure)! Which is almost exactly 30sec after ENG1 reaching 45% NH (at about 11:40) and in next shot (12:19) Pack 1 is already ON and running. :-) So I think this one we solved. ;-) Still no information about bleed air shut-off valve and Hotel mode is mentioned in Maintenance Manual, only crossfeed valve is! So maybe be someone made mistake when creating FCOM and mistakenly put Bleed valve into relation with Prop Brake?
They are operational diagrams for pilot understanding of systems (from an operational manual) not technical diagrams for maintenance personnel (who need a maintenance manual).
More than 2 years as an ATR PIC, but I'm still going through these videos as a refresher.
Damn all these time we pilots always thought Recirc ON + HIGH flow would make the cabin cool fast. Never knew we need to turn off Recirc until now. That's probably the reason why we turn on the Recircs because want more air flowing down our sweaty faces. Thank you so much for this hack.
Tip I use to not forget to put back ovrb valve to auto, is to switch off recirc fan 2.
Great video.. Ten times better than my current CBT for my new ATR type rating. Many thanks all the effort captain. All the best...
I am currently studying my ATR 72 type rating, in particular the whole system with books and docs. It's quite complex and not easy to understand most of the time until I watch your videos. Many thanks Captain!!
Magnar merci merci merci, what you do for us is incredible, sharing your knowledge and helping us through.
@@AllisonLamarre Thank you!
Thanks a lot captain, we are learning a lot from you, I can’t wait to get more and more from a highly experienced captain that you are
Glad to hear it!
@@FlywithMagnarcan you please explain NAMS. Thank you
The same can apply to our cars, they also have recirculating valves and the manuals also recommend not recirculating if you have just entered the vehicle which was parked under scorching sun.
Hello Magnar. I just wanted to thank you for all of your videos. They have been extremely helpful for a relatively experienced pilot switching over to the ATR from the Saab 340. Although similar, the systems on the ATR are unique and your explanations are so clear and helpful Thanks again - from Canada!
Thank you!
Great series of videos. This may be intended for pilots, but as a tech I find it very informative, and indispensable for troubleshooting the aircraft. Much better than my GenFam courses. Thank you for sharing your knowledge and experiences with us all.
Thank you once again Captain for a great video with a lot of good and vibrant explanations. There are definitely always new things to learn about this bird. cheers from Denmark /Thomas
Glad you like them!
Captain, thank you for such an informative video and explanation. I should be grateful if you could pass this along to ALL Wings Air (PT. Wings Abadi Airlines) pilots who seemingly do no know how to activate the pax aircon. They seemingly leave it INOP until well established on climb, just prior to cruise. No doubt they know how to operate the system for the flight deck!
Great work captain. Very well explaination of the systems for some one who wants to learn or refresh his knowledges. Also far more interesting than most of hypnotic WBTs
Sjukt intressant att kolla på! Kärlek från Sverige❤️
Thank you Captain Magnar for this detailed explanation, really an eye opener for myself.
I've experienced a few times while trying to cool the cabin, On hotel mode with HI flow & PL to the gust lock stop, after a few minutes it will trigger Bleed #2 Leak and therefore pack #2 fault. Would really appreciate your thoughts on as to why that may happen..even though the procedure is stated in the manual
Im operating in Malaysia where the OAT is about 25-34 celcius.
A bleed leak alert will close the bleed valve and the pack valve. I have not experienced this, even when it's 35 degrees. But a bleed leak alert must not be reset; the indication must be investigated by maintenance.
Thanks captain magnar, but I didn't notice clearly the reason of turning off the the recirculation fans when it is needed to bring the temperature down
Watch this: th-cam.com/video/1kSyraD4grs/w-d-xo.html
Amazing work Captain, thank you for all these helpful videos!
Very informative Sir, grafics are excellent,👍,🙏
I enjoy a lot your videos they are easy to understand. Thanks.
Great work captain...Thank you
GOOD CLASS, VERY GOOD EXPLANATION. THANKS.
Hello, Captain. What should be done for dual bleed failure? Since bleed air is necessary for cabin pressurization, would an emergency descent be necessary when cruising at higher altitudes to prevent gradual decompression, or should only PACK VALVE 1+2 FAULT checklist be followed?
The cabin pressure will decline gradually, so an emergency descent is not required. Just follow the checklist for PACK 1+2 VALVES FAULT and descent to FL100 or MEA.
Note..not mentioned in the schematic is how the turbine is prevented from damage from ice by the T.I.C valve..
Oh, thanks. I was wondering what that is because it is on the schematic in my airline’s manual. But not mentioned at all. (I haven’t had a chance to look in the ATR manuals yet.)
Hello Capt, Season Greetings to you
Very glad to see you in this, wonderful videos and your simplified version of the systems makes it more easier and interesting to understand this complex airplane. Keep doing more !
P. s u did my check in Bangkok sometime in 2015 and it was a great Memory ..
Many thanks!
Thanks!! Valuable tips!!
Great video! Thanks😊
Very nice capt.
Hello captain , as pilot in ATR 72 500 i really enjoy and i learning more and more from You sir , is There any possibility to make for us a vidéo about power plant thank you captain .
Thank you so much! Currently, I'm working on a a series of videos about the powerplant.
Keep up the good work capt.
Thank you for informative video. Have doubt about regarding rotary knob for temp control. When there is auto temp mode is given then what is use of this rotary knob to control the temp. It is understood when it is in manual mode rotary knob is required to control the temp but when it is an auto mode will that rotary knob make any difference. Kindly explain
In automatic mode, the temperature control knob is used to set the temperature in the cabin/cockpit. In manual mode, the temperature control knob is used to operate the temperature control valve directly. See FCOM DSC.21.2 page 20.
@@FlywithMagnar thank you very much for vlearing doubt
Thank you very much cap good class
Thank you for your detailed explanation vdo
Hello Capt. Magnar, i have a question to ask. On the QRH, if both packs failed, it is said that the max flight time is limited to 80 minutes. is there any specific reason/reference to the limited flight time? thank you very much.
CO2. When both air conditioning packs have failed, cabin air is not replenished with fresh air. This causes the CO2 concentration to increase. With a cabin full of passengers, the 80 minute limitation will limit the CO2 concentration to a maximum of 3%. This is regarded to be safe by EASA.
@@FlywithMagnar very well understood captain. Thank you very much for the reply.
what kind of discomfort to the passenger to be specific is prevented by delaying the opening of the packs?
Please Magnar, could you explain why we don't turn, let's say, the bleed #1 off when we are flying with pack#1 off (inop)? At least the checklist doesn't mention it. Thank you.
Because the associated engine bleed valve has not failed. Let's say pack #1 has failed. When you taxi in, you will normally shut down engine #2 after to minutes. Bleed #1 will then supply pack #2 via the crossfeed valve.
Thank you sir , it really helps
Hello magnar, great videos! Can you say me where I can find the fcom?
Unfortunately, an FCOM is the property of ATR or the owner of the aircraft. The FCOM is customized to the equipment installed in a specific aircraft. Therefore, you will not find FCOM online that can be legally downloaded.
Sir wanted to know in details about NEW AIR MANAGEMENT SYSTEM, kind request to you please make a video on that in details .
I will make a video about it, but I need more information from ATR first.
@@FlywithMagnar will be waiting sir , thanks.
Sir still waiting
Hello :)
Manuel mod- full hot position
duck temperature does not exceed 50 degrees in switch flight cmpt. mode and hot by-pass valve does not open. Temp cont valve open.
Where is the problem?
GREAT VIDEO :)
Hello Captain, thank you for your videos.
On this one, i have a question, related to the mixing chamber. You said that in case of fail of one pack, the mixing chamber supplied the other side. That was what i though also, but a few months ago, with this doubt, a mechanic show me the schematic, and there is one mixing chamber per pack, isolated. Meaning that doesnt have any connection to suplly the other side.
Can i please ask you to clarify this?
Thank you and best regards
It depends how you define "mixing chamber." The mixing chamber I was talking about, is a duct between the pack outlets. It is visible when you remove the floor panels.
Thank you for your answer.
That make me a litlle bit more confused. I was talking about the mixing chamber after the packs. I though there was a single mixing chamber for the 2 packs, as show on cbts and fcom, but i´ve been show that each pack as a mixing chamber, and they do not feed air to the other side or pack, thats why now im a litlle bit confused again.
@@ricardoamado3672, ther mixing chamber is after the packs. If you have other drawings, please share them with me. You will find my email address on my profile.
Air Conditioning on a ATR. Uh huh. Vague to almost non existant-better on the "large"-think PW 127 engines. The 120 engines-ugh. On an airframe that sold large numbers to operators near the Equator.
15 years as a lead heavy MX mech with a FedEx feeder-also dealt with MANY airframes coming out of Central & South America as well as Oceania. Toulouse could learn a few things from Boeing on that subject......
The Cabin Smoke Abatement mod did do wonders-but ya better have your David Clarks on real good.
how much information does a pilot have to know about this system? does a line pilot have to memorize all of the information?
Hello Captain, thank you for such an informative video.
When the airspeed is below 150 kt and retracted for less than 10 mins., the turbo Shutoff Valve opens. What is the significance of that 10 mins limitation?
Does the duct temperature limiter that limits the temperature in the dut at 88 operate in auto and Man mode?
I don't know the answer to that question, but the turbofan is there to improve cooling airflow thorugh the heat exchangers.
Auto mode.
Magnar please write about decreasing maximum payload during hot weather operation
Temperature is one of several factors affecting maximum payload. I have listed them in this video about tale-off performance: th-cam.com/video/AIfwMy-rhig/w-d-xo.html
Nice 👍🏼
супер видео. спасибо
Добро пожаловать
good
captain can you please let me know what source are you using for those panel images to demonstrate for us? (cockpit panel ) or if you can introduce me to a source/ i found one original ATR72-500 belongs to company but not clear . iappreciate
Hi, I use own photographs and drawings made with PowerPoint.
@@FlywithMagnar thank you sir for reply. those beautiful images from cockpit parts drawn by yourself??? imazing. would it be possible to have the overpanel and main and radio panels images?? IF IF it is ok with you. otherwise understandable..
I'm sorry, but I don't have the entire panels, and if I had, I wouldn't give it away.
@@FlywithMagnar thank you captain i absolutely understand. thank you for great videos . i hope you post more and more specially about dark and cold start up
How are you sir can you tell me please that oxygen level of aeroplane is maintan same like ground level when plane flying high attitude
That depends on the aircraft type. In ATR aircraft, the pressurization is controlled by a computer and provides a smooth change in cabin air pressure as we climb and descend. If we use manual override, we should be able to maintain sea level air pressure when flying up to 13,800 ft.
Ok thanks sir I understand but please tell me this oxygen is enough for small children's for breathing on the 8000feet
@@khurramhanif9747 , no problem at all, unless the person, old or young, has a respiratory problem.
Ok thanks sir
@@khurramhanif9747 At normal cruising altidudes, the cabin pressure is about 5,000 to 6,000 feet. This is roughly equivalent to Denver, Colorado.
Hello Magnar,
I am bit puzzled about ENG1 BLEED valve close logic during Hotel Mode. Do you know what is the reason for ENG1 BLEED valve to be closed when prop brake is engaged? Thank you.
Thank you for pointing out this. When I made the video, I used the latest FCOM revision. Unfortunately, the manufacturer made an error here. The last line should not be there. FCOM revisions pre-dating the EDORA (Electronic Documentation for Regional Aircraft) system are correct.
Edit: I was too quick to draw this conclusion. Please read the responses below.
@@FlywithMagnar Thank you for reply. I did checked several of my FCOM dated between DEC 1997 and JAN 2018 and all actually state same information:
"The bleed air shutoff valve automatically closes in the following cases: ..... PROPELLER BRAKE selected ON (for only left bleed valve)"
So now I am puzzled even more. :-) Is this real behavior? Anyone able to observe this in aircraft? I know that it is not usual aircraft state, as typically when you have ENG2 in Hotel Mode (prop brake engage) you don't have ENG1 running. And standard procedure is to release prop brake before starting ENG1. Maybe @mzo could tell us? ;-)
This is getting more and more mysterious. I have FCOM for AT43, AT45, AT72, AT75 (3 revisions), and AT76 (3 revisions). All of them, with the exemption of one, says "The bleed air shutoff valve automatically closes in the following cases: ..... PROPELLER BRAKE selected ON (for only left bleed valve). The 2011 revision of AT76 FCOM does not have this line.
I have done a lot of starts where the propeller brake was ON and we started engine #1 first. During the start, bleed #1 was OFF. It was selected ON after the start and opened immediately. You can see it at 11 minutes in this video: th-cam.com/video/sF8q8bcR8TU/w-d-xo.html
FCOM says "PROPELLER BRAKE selected ON". This might be interpreted in the following way: Bleed valve #1 closes when we SELECT the propeller brake ON.
@@FlywithMagnar My FCOM are for AT45, AT75 and AT72 and I can confirm what you found - all state same. Also in your great video, it is clearly visible, that you can have ENG1 Bleed ON with Prop Brake ON. Do you mean that Bleed will close during Prop Brake engage procedure? And open again when Prop Brake is engaged? That is rather mysterious. Even more as I do not see reason for ENG1 Bleed to be OFF during Prop Brake engagement or even when Prop Brake is ON. Someone having any idea? ;-)
To add even more puzzles: in your video 11:24 - ENG1 Starter ON, around 11:45 ENG1 NH Stabilized and 11:50 ENG1 Bleed ON. This means that between begin of the start procedure and Bleed ON is less than 30sec. My FCOM says: During a starting sequence, the opening of the bleed air shutoff valve is inhibited. You mentioned in the video, that it is inhibited for 30sec. But it seems to be less. I can try to dig through Maintenance Manual, but I would expect Bleed opening to be delayed as function of NH and controlled by MFC, not by timer. But I was so many times wrong when tried to guess supposed ATR systems functions... :-)
By the way another interesting question. As HP air for deicing is not going through Bleed valve, but directly Deice Valve, so I would guess that Deice valve opening should be delayed as well during engine startup, to avoid potential hot start. But surprisingly nothing about that mentioned in FCOM. I would expect same logic to be applied for Deice Valve as for Bleed Valve during ENG start. This would cause AFR AIR BLEED and 1 ENG 2 annunciators on deice panel to cope with status of the Bleed valve. Or I am completely wrong?
Digging through Maintenance Manual Chapter 36: - During the engine starting the bleed air shut-off valve opening is inhibited an consequently the system goes to off. The valve will not open until 30sec after 45% NH engine has been attained. Is Maintenance Manual wrong about blocking opening of Bleed valve until 30 sec after 45% HN? Well I don't think so. MFC only seem to block normal Bleed valve annunciation (you should get FAULT when valve position disagreed with selected position). You can see Pack valve being Fault when Bleed is selected ON (at 11:49). This is due to no pressure available from Bleed1. And around 12:11 you can barely but see crossfeed valve opening (as Bleed1 finally delivers air pressure)! Which is almost exactly 30sec after ENG1 reaching 45% NH (at about 11:40) and in next shot (12:19) Pack 1 is already ON and running. :-) So I think this one we solved. ;-)
Still no information about bleed air shut-off valve and Hotel mode is mentioned in Maintenance Manual, only crossfeed valve is! So maybe be someone made mistake when creating FCOM and mistakenly put Bleed valve into relation with Prop Brake?
Hello captain
Hello
Everything is in diagrams not in real world.... hahahhahahahaah
They are operational diagrams for pilot understanding of systems (from an operational manual) not technical diagrams for maintenance personnel (who need a maintenance manual).