ATR systems - Ventilation and pressurization

Cabin pressurization is, together with the jet engine, the invention that made modern air travel possible. This allowed the airplanes to fly above turbulence and icing. And being a passenger suddenly became more comfortable.
This video examines the ventilation system and the pressurization system in ATR 42 and 72. Other transport airplanes have very similar systems.
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ATR air condition system: • ATR systems - Air cond...
ATR electrical system: • ATR electric systems -...
References:
System description: ATR FCOM.DSC.21
Normal system use: ATR FCOM.PRO.NOP.NSU.21
Attribution:
Aviation Herald: Excessive cabin pressure avherald.com/h?article=4543f99...
Follow Fly with Magnar: / 1140864699685560

[@GiuseppeSRedSky]

Captain, I'm a military ATR pilot and I find your video really good!!

[@qman9081]

Going into ATR initial may 16th.. can’t wait. Thank you for your videos!

[@FlywithMagnar]

All the best!

[@ahmedbida3202]

I’ve learned a lot from this video even though. I’ve done my ATR type rating two years ago. Thanks a lot Magnar, looking forward to learn more from you.

[@christopherpeters5916]

On that note, descend

[@christopherpeters5916]

Then, work the problem. By check list. Notify atc

[@christopherpeters5916]

Augetzhich!

[@zerggon]

Your content is fantastic Magnar. I very much prefer your instruction over ACOS. Your real world references are invaluable.

[@psidhu1979]

Always a pleasure to watch your highly informative and insightful videos

[@FlywithMagnar]

Glad you like them!

[@jcommtube]

Magnar, I'm grateful for you channel and all of the excellent videos / tutorials. A true delight to watch & learn, with each & every detail explained clearly! While I do not have MFS and even less the new ATR that was released for that game, I came to your channel when searching for material regarding the ATR, and although it's mainly focused in that type, there's a worth of other tutorials, hints, details that are cross-platform and you explain remarkably !!!

[@healdude7206]

Thank you so much captain.Your content is so easy to understand and stays in the memory forever. I go through one system everyday after waking up in the morning and all of them before ir/ppc.

[@sjackson666]

Dear captain thank you so much. I am big fan of yours. Please continue your videos. Especially ATR systems are fantastic. Could you do cockpit flows and maybe engine start sequence video in real cockpit please? many thanks.. all the best captain

[@duypham5533]

Many thanks to you from Vietnam sir, such a detailed pressurization system CBT ever ❤🎉

[@joteord]

Absolutely great video Captain, I liked a lot the part of it talking about how the pressurization system works during a flight following the graph, Keep up the good work, I hope you get back to to business ASAP, subscribed!!!

[@FlywithMagnar]

Glad you enjoyed it

[@factvibes3669]

Hey captain it's very useful for Maintenance department also so thanks for everything

[@christopherpeters5916]

Sadistic. Love it, Magnar

[@aviationtalkandtutorials2456]

Very informative video, thanks capt.

[@henrirakotozafy6754]

excellent, thanks Capt!

[@130sogair]

Thank you so much captain

[@miguelrozo5975]

Excelente video

[@mrturboprop1743]

Hello Captain Magnar, What is the reasoning behind the mech call horn being sound when Exhaust Mode is pushed to OVBD? Thanks for your reply, always love your videos.

[@FlywithMagnar]

When the Exhaust Mode pushbutton is set to OVBD, the extract fan stops. This means that the avionics are not cooled any more. Therefore, the horn is activated as a reminder to start the fan again.

[@mrturboprop1743]

@@FlywithMagnar understood, thanks captain

[@Smith212]

Thank you very much Captain

[@rockerkunal]

you are fantastic!

[@shahidulislam1419]

Thank you sir, for your nice Video...

[@be3373]

Here in the Eastern Arctic of Canada, on the ground, the overboard valve stays in the full closed, we want to keep the heat in the airplane! 😁 Thanks for the videos. Always learn something new. Cheers

[@FlywithMagnar]

We did the same in Norway. Thank you for your comment!

[@factvibes3669]

Hello magnat sir in ventilation system you told one hole is there just behind oxygen discharge that is for water drain from emergency hatch which is located above in cockpit its not fro battery ventilation battery ventilation vent is below it sir

[@GuLa-wh7ls]

Hello sir, I am looking for the official source of this information, how did you know that ? Cause a mech also told me that but i can’t find the information in the FCOM

[@nitinpandey656]

Very nice videos ....sir! Please make some more videos something about fuel leak , Engine flameout @ (take off, inflight, cruise ,during landing), lo pitch inflight,etc!!

[@FlywithMagnar]

Thank you! Currently, I'm working on the fuel system, which will include fuel leak. Then, I will do the powerplant, which will consist of 4 videos. Please be patient, it takes some time to put the pieces together.

[@nitinpandey656]

@@FlywithMagnar Thank you sir shall wait for them. 🙏

[@KRZYMANIAK]

Great video(s)! Do you have a good procedure for controlling cabin pressure manually without too much discomfort?

[@FlywithMagnar]

It's called patience. You move the knob a bit and wait for the indicators to stabilise. Then you repeat until the desired cabin rate of climb/descent is achieved.

[@KRZYMANIAK]

@@FlywithMagnar I have experienced this first hand and you’re right patience is primary. Regarding a MEL scenario do you think it would it be best to depart with the the the cabin in full decrease? So the pressure of the cabin can keep of with the climb? Thanks for such a swift response.

[@FlywithMagnar]

MEL is a bit funny. 21-30-01P states that if the pressurizaiton system is inoperative, and the manual mode is operative, you shall depart with overboard valve fully open and MAN RATE knob set to max increase. 21-31-01P states that if the automatic pressurization control is inoperative, you shall set cabin altitude in accordance with the published table. I'm not sure which postion of the MAN RATE knob is the best. I would probably depart with the knob set to 9 o'clock position. When you depart, the outflow valves are fully open. They start to close after you have become airborne. The automatic controller will then descend the cabin back to departure airport elevation and maintain it until you are 3,500 feet above the airport. Then, the cabin will start to climb with the aircraft.

[@2kMania301]

Hi Magner, do you recommend keeping the cockpit comms hatch open until after the no 1 engine is started? In this way the overboard valve is open so less of a pressure surge from the exhaust fan when the hatch is closed? Thanks

[@FlywithMagnar]

Yes, that is the recommended procedure. You can close the communication hatch any moment after the starter pushbutton is pressed, as this action causes the extract fan to stop.

[@boyvanurk9854]

Hello Magnar, thank you for another highly informative video. I'm just indulging into the ATR systems and hope not to stalk you too much with questions. This is the first time I 'meet' an aircraft which does apparently not have an overpressure relief valve protecting the cabin structure against overpressure when e.g. the outflow valves remain closed. Would you know why this manufacturer choose not to make use of such a relief valve? Kind regards, Boy

[@FlywithMagnar]

Thank you for your response. It might not been described clearly enough in the video, but an overpressure relief valve and a negative pressure relief valve are fitted on both outflow valves.

[@boyvanurk9854]

@@FlywithMagnar Thank you for your reply. Good to hear that overpressure relief valves are installed on the outflow valve system. That brings things in line with other aircraft I know. On those other types there was not such a procedure as to switch off packs because the overpressure relief valve would sufficiently protect the airplane. One of 'my' types was the Fokker 50 which had some system commonality with ATR. That aircraft also did not have such a procedure. Would you know the background why ATR choose to treat the overpressure case as so critical that "packs off" was introduced? In the example where the F/O's window was blown out; was that a failure of the outflow valves ánd failure of the relief valve at the same time? Happy flights, Boy

[@FlywithMagnar]

@@boyvanurk9854 , the overpressure procedure in ATR was revised to include "packs off" after the incident where the side window was blown out. I haven't seen the report, but assume the outflow valves were closed for some reason and that the relivef valve was inoperative as well.

[@pylt93]

I have a question: how does pressurization work in a flight between 2 high elevation airports, let’s say Bogota at 8360 ft and Rionegro at 7035ft. I ask because in the graph cabin altitude doesn’t even get close to 8360 ft

[@FlywithMagnar]

ATRs operating at airports with high elevation are modified to avoid excessive cabin pressure warning. I am not 100% sure how the pressurization system works at such altitudes. As mentioned in the video, the cabin will maintain the elevation of the departure airport until reaching 3500 ft above the airport elevation. Then, it will be adjusted in accordance with aircraft altitude, but it will also take into consideration the landing elevation. Whether the cabin will descend below airport elevation during cruise, I don't know.

[@benwsibley]

Hey there captain , is there any way to get hold of the FCOM online? I’m really interested in the ATRs and would love to learn more!

[@FlywithMagnar]

I'm sorry, but no. The manuals are the property of the operators.

[@benwsibley]

Ok.Thank you for the reply!

[@dionneboyce9836]

Captain, with excessive delta P the procedure calls for the pack valve to be closed? What then happens to the bleed air going to the pack (since the bleed valve is still opened)? is it released via the overpressure switch?

[@FlywithMagnar]

No, when the pack valve is closed, the bleed air in the duct doesn't move anywhere.

[@dionneboyce9836]

​@@FlywithMagnar Ok. Thank you for clarifying. In theory, it would be similar to if the engine is running and the bleed valves are closed (e.g. takeoff with bleeds OFF). Many thanks for your swift response. Keep up the great work!

[@pedrosanchezzambrano9174]

Greetings ... What exactly is that piece that hangs from the lower area of ​​the ATR when they are docked at the airport?

[@FlywithMagnar]

Do you mean what you see at 8:07? That is the tail prop. It is a strut that is attached to the tail bumper when the aircraft is parked on the ground. It prevents the tail from tipping when there's to much weight (people or cargo) at aft part of the aircraft.

[@tauhidalquader]

Very deep.

[@shivapoudel9059]

nice sir

[@leomartinez7983]

What happens if the aircraft is on ground, still pressurized and the door is opened? (Airbus)

[@wizhippo]

I know pax valve is the right answer. But would dumping also help? Should that damage everyone’s face ears?

[@FlywithMagnar]

Dumping the cabin pressure will result in a rapid decompression. A better solution would be to select the overboard valve to overboard. But this is not necessary. With the pack valves off, the cabin pressure will start to decrase.

[@chomanthapa]

So Extract fan is pushing air to the battery compartment and expelling it to atmosphere?

[@FlywithMagnar]

Yes, that is correct.

[@ronilsonbarbosa4410]

Where can I find the Fcom with full details of the systems ? Best Regards

[@FlywithMagnar]

FCOM, together with many other manuals, are distributed to the pilots when they start their type rating training. It's a large document; FCOM for ATR 72-600 has more than 2,600 pages. It can be ordered from ATR.

[@chris22capt]

I heard the new ATR has a new pressurization panel in the cockpit. Is there any new function that come with the new panel or is it just a look upgrade?

[@FlywithMagnar]

There are some changes: Landing elevation is set by the FMS, and there's only one outflow valve, but with two controllers.

[@chris22capt]

@@FlywithMagnar is the high rate p/b still there or is it completely auto now?

[@FlywithMagnar]

@chris22capt, that pushbutton is removed. Everything is automatic.

[@chris22capt]

@@FlywithMagnar that's a nice upgrade I've to say

[@carlosbecerra176]

Can you explain me why do you use 30 in the PA formula, please?

[@FlywithMagnar]

When QNH deviates from standard 1013.25 hPa, the pressure altitude changes with approximately 30 feet per hPa. This number is easy to remember and use for quick calculations. The exact value depends on altitude and temperature. Video reference: 11:07.

[@carlosbecerra176]

@@FlywithMagnar tks, your videos of ATR are really great.

[@mhayling]

At 19:46 it looks like two electrical conductors are exposed on an orange connector under the glare shield. Sketchy!!!

[@humlakullen]

I'm confused... You mentioned that one of the reasons the extract fan would automatically stop, is because of smoke. Then, in case of smoke, the overboard valve would partially open in order to get rid of the smoke. But since the extract fan is next to the overboard valve, wouldn't smoke removal be more efficient with the fan on..?

[@FlywithMagnar]

The logic is that the extract fan will stop when there's a smoke alert, as this will prevent smoke form being sent back to the cabin. The overboard valve remains closed and the underfloor valve remains open. When the pilot selects exhaust mode pushbutton to overboard, the underfloor valve will close and the overboard valve will open partially. The extract fan remains off because the pushbutton also controls the fan. This is not a problem, as differential pressure will provide a good flow of air (and smoke) through the overboard valve.

[@humlakullen]

@@FlywithMagnar That was quick:-). Yeah, I guess there’s some logic to that. Thanks a bunch. Awesome videos by the way.

[@kuyanolitv644]

♥️♥️♥️♥️♥️😎

[@nanba25]

For a non-pilot, like myself, it's very hard to follow, although the physical principles are just simple. Not my favorite domain of this aircraft…

[@user-lg4yz2rh9f]

little not correct, battery discharge air not from small hole near oxy relief glass, battery air discharge position lower and bigger hole LH side near NLG bay

[@FlywithMagnar]

Yes, I'm painfully aware of this mistake.

[@alessandrocipullo]

that hole (the one beside the oxy relief valve) in real is a WATER DRAIN coming from the HATCH DOOR.

[@FlywithMagnar]

@@alessandrocipullo, AHA! Thank you so much!

[@alessandrocipullo4171]

@@FlywithMagnar thanks to you !…we never finish to learn in aviation and on the planes👍😉and I learned so much from You!