dashtrasher
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CRJ Systems
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flying4food
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I have a question and I am an A&P and I.A. so this system question I am having a bit of a problem with since it goes beyond some normal logic of jet engine systems I have been an inspector on in the past. I am an FO on the CRJ now. Its about on a cross bleed start with the APU inop. Our cockpit operatons handbook says to make sure the 14th stage is clicked in that is the PBA buttons in or on as they always are anyway in normal ops. It used to only say 14th stage. ( This is Pinnacle ) Now it say both 14th and 10th stage PBA's pushed in. I was told by a senior Capt in the training dept that the new book is wrong and it doesn't matter what position the 10th stage bleed buttons are the tenth stage bleed valves will auto open when pushing the star PBA.
But elsewhere I am told in the book for such things as a starter not disconnecting at 55% we are to press the stop PBA and if that doesn't work and were doing the star with the APU operational the next item would be to shutoff APU LCV then the 10th stage isolation valve then 10th stage bleed valves and then if that doesn't work shut down the engine with the thrust lever all in the sequence stated to progressively find the source the fault etc... This goes somewhat against the former statement that it doesn't matter what position the 10th stg bleed valve is in.
He went on to say in the top paragraph discussion that only the 14stage bleed valve PBA's are required to be pushed in because they are designed to fail in the open position or if electrical power is lost they will open and this will ummmmmmmmm hmmmmmmm have something to do with protecting in an odd situation the engine from getting a hung start?
Please can someone help my feeble 20 year mechanics brain from melt down. I know the tenth stage bleed pba's are out and the isol valve and LCV are in on a normal start and the 10th stage valve open automatically but somehow getting lost here.
But elsewhere I am told in the book for such things as a starter not disconnecting at 55% we are to press the stop PBA and if that doesn't work and were doing the star with the APU operational the next item would be to shutoff APU LCV then the 10th stage isolation valve then 10th stage bleed valves and then if that doesn't work shut down the engine with the thrust lever all in the sequence stated to progressively find the source the fault etc... This goes somewhat against the former statement that it doesn't matter what position the 10th stg bleed valve is in.
He went on to say in the top paragraph discussion that only the 14stage bleed valve PBA's are required to be pushed in because they are designed to fail in the open position or if electrical power is lost they will open and this will ummmmmmmmm hmmmmmmm have something to do with protecting in an odd situation the engine from getting a hung start?
Please can someone help my feeble 20 year mechanics brain from melt down. I know the tenth stage bleed pba's are out and the isol valve and LCV are in on a normal start and the 10th stage valve open automatically but somehow getting lost here.
DoinTime
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Wouldn't your brain be put to better use looking at porn?
On a serious note....I stoped trying to find better ways of doing things after having to do a carpet dance over 'my own' version of the deice procedures. If you follow the procedure outlined in your FCOM sh!t works pretty well and your a$$ is covered.
On a serious note....I stoped trying to find better ways of doing things after having to do a carpet dance over 'my own' version of the deice procedures. If you follow the procedure outlined in your FCOM sh!t works pretty well and your a$$ is covered.
Yes dats true but they still ask you dose silly questions in da "orals," ooops excuse me "verbals" even though its "speld" out pretty good in da QRH.
Due tell about da icing procedure? The one dat werkz pretty good about turning on da wing early before hittin da clouds so the wing temp sensor warms up seeing that two tings set off da wing ice eicas msg....air pressure and temp sensor in the inboard wing quack I mean duck.
Due tell about da icing procedure? The one dat werkz pretty good about turning on da wing early before hittin da clouds so the wing temp sensor warms up seeing that two tings set off da wing ice eicas msg....air pressure and temp sensor in the inboard wing quack I mean duck.
The left and right 10th stages open automatically when start is pushed. However, a cross-bleed start for the CRJ (at least at my company) requires advancing the thrust lever until you get 60 psi from the operating engine. The only way you can read the psi is by going to the ECS Eicas page and opening the 10th stage on the operative engine. Unless you do this, there's no pressure indication. Once you've verified the pressure, you can then start the other engine (knowing you have sufficient pressure for the air turbine starter). That's the reasoning I've heard, anyway.
Yes that the way I understood it... at least until tonight that on a cross bleed start ( and yes the power lever must be fwd to give sufficient pressure on the tenth stage bleed system / "ECS" synoptic eicas page) that you must have the tenth stage bleed open on the operating engine to get pressure there for the automatic opening of the non operating ( at the moment) starter valve unti star button pushed.
But the pretty knowledgable fellow said that I didn't have to have that 10stg open because when I hit the starter that required bleed valve would open anyway. ??? Well then you wouldn't be able to verify the bleed pressure before hitting start if we did it that way would we. At least in my simple minded thought process of course, but I said nothing.
And remember one time in the sim using our old QRH supplemental procedure we did it according to the book and only had 14th stage open / pushed in PBA's (New book specifies 1oth stage also) and because the tenth stage bleed PBA's weren't pushed in the starter didn't wizz up.
But the pretty knowledgable fellow said that I didn't have to have that 10stg open because when I hit the starter that required bleed valve would open anyway. ??? Well then you wouldn't be able to verify the bleed pressure before hitting start if we did it that way would we. At least in my simple minded thought process of course, but I said nothing.
And remember one time in the sim using our old QRH supplemental procedure we did it according to the book and only had 14th stage open / pushed in PBA's (New book specifies 1oth stage also) and because the tenth stage bleed PBA's weren't pushed in the starter didn't wizz up.
Some thoughts
hmmm,
As an A&P/I.A. you need to know how to take it apart and put it back together plus a lot of other things that a pilot could not possibly do from the cockpit.
As a pilot, the need to know or do all of that simply does not exist. Focus on what you can do from the cockpit and how to "operate" (not repair) your airplane. You do not need to know how to build the thing. It's sort of comparable to a computer, i.e., you don't have to know how to "write" the program in order to "use" the software and you don't need to know which transistor on the graphics board makes the sky blue and the ground brown. My advice is .... don't try.
With reference to the simulator keep in mind that it is a "computer". When they build the thing, the "hardware" is designed to the specs that existed for that aircraft at the time the simulator was built. The "software" of the simulator is also written to comply with or duplicate the functions and procedures that existed at the time the software was written.
When a significant change is made in the actual aircraft and that in turn results in a change in operating procedure, the simulator program has to be rewritten (software) and sometimes the simulator (hardware) has to be modified before the computer can respond to the "new" way and duplicate the aircraft.
It is not unusual to have something change in the "real aircraft" and a new procedure implemented before the simulator is modified. Sometimes the particular company never goes to the trouble/expense of changing the simulator (unless the "new" item would make the operation unsafe). A good simulator flies like the airplane ... and is close enough to allow the pilot to learn how to operate the real aircraft safely. However, it seldom duplicates every little detail to perfection. There will be minor differences from time to time. Usually insignificant.
As a pilot, all you really need to know is how to accomplish the particular start. Your check list and procedures will tell you how to do that and what sequence to follow. If your simulator is setup with the "old" procedure, ignore it and follow the "new" procedure as outlined in your manuals and checklist.
I suggest you spend less time trying to "build" the airplane. Who cares what valve or stage opens when? Just follow your procedures. If it works, press on. If it doesn't, write it up and let the folks on the ground do their job. Separate the need to know from the nice to know and focus on the former. It will make your life as a pilot a lot easier.
It may not be easy to do that when you have the background of an A&P/I.A. but it will sure help your "new" life as a pilot. I suggest that you don't try to be both at the same time.
Have fun.
hmmm,
As an A&P/I.A. you need to know how to take it apart and put it back together plus a lot of other things that a pilot could not possibly do from the cockpit.
As a pilot, the need to know or do all of that simply does not exist. Focus on what you can do from the cockpit and how to "operate" (not repair) your airplane. You do not need to know how to build the thing. It's sort of comparable to a computer, i.e., you don't have to know how to "write" the program in order to "use" the software and you don't need to know which transistor on the graphics board makes the sky blue and the ground brown. My advice is .... don't try.
With reference to the simulator keep in mind that it is a "computer". When they build the thing, the "hardware" is designed to the specs that existed for that aircraft at the time the simulator was built. The "software" of the simulator is also written to comply with or duplicate the functions and procedures that existed at the time the software was written.
When a significant change is made in the actual aircraft and that in turn results in a change in operating procedure, the simulator program has to be rewritten (software) and sometimes the simulator (hardware) has to be modified before the computer can respond to the "new" way and duplicate the aircraft.
It is not unusual to have something change in the "real aircraft" and a new procedure implemented before the simulator is modified. Sometimes the particular company never goes to the trouble/expense of changing the simulator (unless the "new" item would make the operation unsafe). A good simulator flies like the airplane ... and is close enough to allow the pilot to learn how to operate the real aircraft safely. However, it seldom duplicates every little detail to perfection. There will be minor differences from time to time. Usually insignificant.
As a pilot, all you really need to know is how to accomplish the particular start. Your check list and procedures will tell you how to do that and what sequence to follow. If your simulator is setup with the "old" procedure, ignore it and follow the "new" procedure as outlined in your manuals and checklist.
I suggest you spend less time trying to "build" the airplane. Who cares what valve or stage opens when? Just follow your procedures. If it works, press on. If it doesn't, write it up and let the folks on the ground do their job. Separate the need to know from the nice to know and focus on the former. It will make your life as a pilot a lot easier.
It may not be easy to do that when you have the background of an A&P/I.A. but it will sure help your "new" life as a pilot. I suggest that you don't try to be both at the same time.
Have fun.
The following... is just the point " Separate the need to know from the nice to know and focus on the former. It will make your life as a pilot a lot easier. "
In the Oral / Verbal they ask the question put forth here. Thought someone might know the answer and be able to explain it better than the check guy who it explained it to me. ( different from the oral guy) The procedure has not changed. Only the book was missing the step and now the step was covered. It was always taught the same way. Just not in depth in ground and then comes along an examiner and asks you the question on your oral.
Thanks for the time to make a well thought out response. The exert about being an A&P I.A. was only to give depth that the person asking the question does have a decent understanding of systems and being an A&P the Oral guy expects me to know a little more about systems then the rest so says he.
So... any understsanding in this arena?
In the Oral / Verbal they ask the question put forth here. Thought someone might know the answer and be able to explain it better than the check guy who it explained it to me. ( different from the oral guy) The procedure has not changed. Only the book was missing the step and now the step was covered. It was always taught the same way. Just not in depth in ground and then comes along an examiner and asks you the question on your oral.
Thanks for the time to make a well thought out response. The exert about being an A&P I.A. was only to give depth that the person asking the question does have a decent understanding of systems and being an A&P the Oral guy expects me to know a little more about systems then the rest so says he.
So... any understsanding in this arena?
Last edited:
KingAirKiddo
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Ouch...my head hurts!!!
Hmmm,
First of all, why do you have to ask such difficult questions? I'm going to have to take some Tylenol to get rid of the headache brought on by racking my inept brain for an answer to your question
Our study guide says the following...maybe it will help you visualize what happens, maybe it won't:
1. All valves associated with the 10th stage bleeds are spring-loaded CLOSED and require air pressure for them to move open.
2. On the entire Bleed Air panel, the L & R 14th stage valves are the only ones that are spring loaded OPEN, and they too need air pressure to move closed.
3. Because all valves need air pressure to move them, they do not always move when the appropriate switch is pressed. It is easiest to remember that when the switches are selected, IN is OPEN and OUT is closed. The vavlves will move when the air pressure reaches them.
The book also states that for a crossbleed start the operating engine's RPM needs to be at least 85% N2 or higher, so that would be another way to indirectly check for appropriate pressure without actually checking the ECS synoptic page.
So in other words, the 10th stage ISOL valve is normally closed to separate the left and right side distribution ducting. It opens automatically during engine start to ensure a supply to both engines, regardless of pneumatic source.
Hope all this helps...think I'll go apply a cold washclothe to my head now.
Hmmm,
First of all, why do you have to ask such difficult questions? I'm going to have to take some Tylenol to get rid of the headache brought on by racking my inept brain for an answer to your question
Our study guide says the following...maybe it will help you visualize what happens, maybe it won't:
1. All valves associated with the 10th stage bleeds are spring-loaded CLOSED and require air pressure for them to move open.
2. On the entire Bleed Air panel, the L & R 14th stage valves are the only ones that are spring loaded OPEN, and they too need air pressure to move closed.
3. Because all valves need air pressure to move them, they do not always move when the appropriate switch is pressed. It is easiest to remember that when the switches are selected, IN is OPEN and OUT is closed. The vavlves will move when the air pressure reaches them.
The book also states that for a crossbleed start the operating engine's RPM needs to be at least 85% N2 or higher, so that would be another way to indirectly check for appropriate pressure without actually checking the ECS synoptic page.
So in other words, the 10th stage ISOL valve is normally closed to separate the left and right side distribution ducting. It opens automatically during engine start to ensure a supply to both engines, regardless of pneumatic source.
Hope all this helps...think I'll go apply a cold washclothe to my head now.
Yes, KingAirKiddo, That was a very good post and answer. Yes ahahaha I know it is hard to read how I write. Might need to apply a cold beer and aspirin with that cold washclothe to your head. Thanks for the reply and answer.
------
The one remaining question is that of the 14th stage valves.
If the 14th stage valves are pneumatically closed and are spring loaded to the open position..... Reason being they are set up this way so if somehow maybe if the wire going to them broke that you could still get air to the Anti Ice systems. Right?
Well in our book it has us make sure that the 14 stage PBA's are pushed in (open position).
Well I was told that the reason we make sure they are open are to help ensure against a hung start if we were to loose electrical power........... This comes from a very highly technically oriented check airmen at the top of the seniority list (not not JH at Pinnacle) of which I have a lot of respect for.
------
The one remaining question is that of the 14th stage valves.
If the 14th stage valves are pneumatically closed and are spring loaded to the open position..... Reason being they are set up this way so if somehow maybe if the wire going to them broke that you could still get air to the Anti Ice systems. Right?
Well in our book it has us make sure that the 14 stage PBA's are pushed in (open position).
Well I was told that the reason we make sure they are open are to help ensure against a hung start if we were to loose electrical power........... This comes from a very highly technically oriented check airmen at the top of the seniority list (not not JH at Pinnacle) of which I have a lot of respect for.
KingAirKiddo
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- Jan 8, 2002
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- 465
Hmmm,
I'd agree with the first part...it sounds logical to me.
I'm not really sure on the hung start theory though...I'm having a hard time visualizing what he is talking about. I'll read back through some of my stuff, though, and if it "clicks" for me I'll post another reply here.
Take care,
KAK
I'd agree with the first part...it sounds logical to me.
I'm not really sure on the hung start theory though...I'm having a hard time visualizing what he is talking about. I'll read back through some of my stuff, though, and if it "clicks" for me I'll post another reply here.
Take care,
KAK
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