A320 - Arming Approach
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A320 - Arming Approach
In the Airbus you can activate the approach at any altitude but I was told if you arm (APPR on FCU) the approach above 8,000 ft AGL, the autopilot and FDs disconnect. Does anyone have a reference for it?
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Doesn't happen else how would you land at a high altitude airport? We used to operate A320s in Addis Ababa at 7,800' elevation! It will take the FMS to approach phase which could be awkward if you do it by mistake in the cruise; to get back to the cruise phase just re-enter the cost index.
It's been a while and two new type ratings since I flew the Airbus so don't take my word for it and I can't give a reference but I'm sure that others will answer and either confirm of dispute what I say. Either way, enjoy the 'Bus, it's great!!
Happy landings
It's been a while and two new type ratings since I flew the Airbus so don't take my word for it and I can't give a reference but I'm sure that others will answer and either confirm of dispute what I say. Either way, enjoy the 'Bus, it's great!!
Happy landings
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It's apparently a function of AGL not MSL. I was told if you were on an ILS above 8,000 AGL and were to arm the approach on the FCU, the autopilot would disengage and the FDs disappear. It's actually valid for any instrument approach. I haven't found any reference to it nor tried it. I was hoping someone could confirm this.
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AGL versus MSL; could be but I have no memory of this. I'm sure I have armed approach this early with no ill effects before but we'd best wait till a current 'Bus driver responds rather than cloud the issue with my half remembrances!
I'll lurk and look out for a more complete answer to appear.
Happy landings!
I'll lurk and look out for a more complete answer to appear.
Happy landings!
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Originally Posted by Bubi352
It's apparently a function of AGL not MSL. I was told if you were on an ILS above 8,000 AGL and were to arm the approach on the FCU, the autopilot would disengage and the FDs disappear.
But maybe not the best procedure to arm an ILS too early as spurious or false capture for LOC and/or G/S may occur.
RNAV is a different matter, and I can remember arming RNAV approach well above 10000 feet with no adverse consequence.
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Saw this thread yesterday. Tried it today to see what would happen. Armed approach out of 16,000' (9800' AGL) when cleared for the approach. Worked just fine. Stayed at CAT I until around 8000' AGL then went to CAT 3 automatically.
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This discussion came up supposedly because someone armed APPR the approach on a very long final. The autopilot and FDs apparently went OFF as a result. This is a 'story' that was passed along from pilot to pilot. You know how it goes... I wanted to see if there was any validity to it. I am waiting for my recurrent this week to try it also. I appreciate guys!
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When training on the 320 my instructor told me this:
He thought if the flight path is all programmed in, and the aircraft will follow it until the intercept of the ILS, why not press the APP button early? - It is very dangerous, because the ILS reciever then controls the aircraft movement (speaking figuratively) if it recieves anything. So pressing it over the Atlantic would probably do nothing, but pressing it anywhere where you might recieve a signal of the same frequency as the ILS you intended to intercept will cause a capture. That might have some negative side effects cruising at FL350, if the machine pitches down and starts turning...
What you are doing is escentially giving radio signals a higher priority than the FMS signals towards the autopilot.
Boys, it is not a toy!
Nic
He thought if the flight path is all programmed in, and the aircraft will follow it until the intercept of the ILS, why not press the APP button early? - It is very dangerous, because the ILS reciever then controls the aircraft movement (speaking figuratively) if it recieves anything. So pressing it over the Atlantic would probably do nothing, but pressing it anywhere where you might recieve a signal of the same frequency as the ILS you intended to intercept will cause a capture. That might have some negative side effects cruising at FL350, if the machine pitches down and starts turning...
What you are doing is escentially giving radio signals a higher priority than the FMS signals towards the autopilot.
Boys, it is not a toy!
Nic
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To give it a try? Are you lot mad? I hope that was done in a simulator and not with paying passengers on board! You are paid to fly from A to B as quickly as possible, and as safely as possible - not faff about as a test pilot playing with your huge toy!!!
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Well, Sir Herbert, I agree, you just used different words!
- that is no problem, as I explained above, because the FMS will just fly whatever you programmed into it.
You guys should be flying something that has the pilot make the choice of "NavSource", like my little CRJ. That makes it obvious what kind of signal is being used to compute autopilot commands.
Nic
I can remember arming RNAV approach well above 10000 feet with no adverse consequence
You guys should be flying something that has the pilot make the choice of "NavSource", like my little CRJ. That makes it obvious what kind of signal is being used to compute autopilot commands.
Nic
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Our SOP says:-
Certainly 25 nm ICAO ILS protection zone is to be observed.
VR
The APPR pb shall not be pressed until:
• The ILS is tuned and identified.
• Clearance for the approach has been received.
• The aircraft is on an acceptable intercept heading.
• Raw data confirms correct sensing.
• The aircraft is not laterally displaced to the extent that a false capture may occur.
• The ILS is tuned and identified.
• Clearance for the approach has been received.
• The aircraft is on an acceptable intercept heading.
• Raw data confirms correct sensing.
• The aircraft is not laterally displaced to the extent that a false capture may occur.
VR
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Originally Posted by Sir Herbert Gussett
To give it a try? Are you lot mad? I hope that was done in a simulator and not with paying passengers on board! You are paid to fly from A to B as quickly as possible, and as safely as possible - not faff about as a test pilot playing with your huge toy!!!
There is a multitude of stuff you can try in flight with absolutely no ill effect, as long as it does not compromise the safety of the flight. Of course, both crew members must be involved in the process.
Is there a danger to give it a try and arm the approach at 20000 feet, absolutely none, as long as you're ready to intervene if the aircraft is not doing what you expect him to do.
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Confiture,
well at 20000' it may be recoverable. But maybe is a pretty bad word in the way I operate an airliner.
At FL350, as the boys wrote, it might dive you into a highspeed stall, intervene with traffic below. You have people walking, trolleys loose, hot drinks being served, and you would risk the jerk of a sudden intercept? Quite dangerous, I'd say.
What's so hard to understand about this problem? The ILS reciever becomes "hot" upon pressing that button, AND having an ILS approach programmed into the FMS. Any signal of the same frequency as the preprogrammed ILS will trigger an intercept, if strong enough. The FMS and the ILS reciever are intermingled on this aircraft.
No toy, I'll stick with that!
Nic
well at 20000' it may be recoverable. But maybe is a pretty bad word in the way I operate an airliner.
At FL350, as the boys wrote, it might dive you into a highspeed stall, intervene with traffic below. You have people walking, trolleys loose, hot drinks being served, and you would risk the jerk of a sudden intercept? Quite dangerous, I'd say.
What's so hard to understand about this problem? The ILS reciever becomes "hot" upon pressing that button, AND having an ILS approach programmed into the FMS. Any signal of the same frequency as the preprogrammed ILS will trigger an intercept, if strong enough. The FMS and the ILS reciever are intermingled on this aircraft.
No toy, I'll stick with that!
Nic
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At FL350, as the boys wrote, it might dive you into a highspeed stall, intervene with traffic below. You have people walking, trolleys loose, hot drinks being served, and you would risk the jerk of a sudden intercept? Quite dangerous, I'd say.
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Whilst not wanting to sound overly dramatic, I would be rather concerned if my colleague started arming approach at FL350! If the question is to find out if the thing will arm above 8000 feet, then fine, arm it passing FL100 or so, where I'm pretty sure I can handle most AP-malfunctionings without raising my bloodpressure. But to go experimenting with mode selections in cruise where your options are somewhat limited should anything go wrong, does not make me feel very comfortable.
In these electronic jets, little things sometimes have big consequences! So yes jtr, I agree that the APPR pb is not guarded. But do you want to be the one to find out there is some undiscovered programming glitch? (like the guys who found out that in some cases after arming approach, the aircraft will not pitch up during the subsequent go around, in stead heading steadily towards the ground at increasing speed)
In these electronic jets, little things sometimes have big consequences! So yes jtr, I agree that the APPR pb is not guarded. But do you want to be the one to find out there is some undiscovered programming glitch? (like the guys who found out that in some cases after arming approach, the aircraft will not pitch up during the subsequent go around, in stead heading steadily towards the ground at increasing speed)
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Dear PENKO, ZONNAIR, NVpilot,
As said by NVpilot, I did armed it in flight (not a simulator) at FL350 to test it after reading the original post.
Saying that that is dangerous, people moving in the plane, bla bla, bla bla, is stupid. Those of you who alledged that what I did is dangerous, you have no idea of how the system works... and that is dangerous!
APP briefly armed at FL350 (as it was the case) will do nothing! Even if you do by coincidence have an ILS frequency in the area where you are equal to the one you entered in RADNAV page, and the aircraft receives it at FL350 and captures it, then the only thing you have to do is press ALT or pull HGD. That`s it!
And no, it will not pitch down, because it will do LOC* before...
And here is another hint! Press ILS switch on FCU, as I did... and if you see no LOC or GS indication... the aircraft is not receiving any ILS signal, hence it will capture nothing!
So dangerous what I did...
Cheers
As said by NVpilot, I did armed it in flight (not a simulator) at FL350 to test it after reading the original post.
Saying that that is dangerous, people moving in the plane, bla bla, bla bla, is stupid. Those of you who alledged that what I did is dangerous, you have no idea of how the system works... and that is dangerous!
APP briefly armed at FL350 (as it was the case) will do nothing! Even if you do by coincidence have an ILS frequency in the area where you are equal to the one you entered in RADNAV page, and the aircraft receives it at FL350 and captures it, then the only thing you have to do is press ALT or pull HGD. That`s it!
And no, it will not pitch down, because it will do LOC* before...
And here is another hint! Press ILS switch on FCU, as I did... and if you see no LOC or GS indication... the aircraft is not receiving any ILS signal, hence it will capture nothing!
So dangerous what I did...
Cheers