ILS Training
02-18-2009 | 03:36 PM
#21
Airport Hobo
Joined: Apr 2007
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The altitudes on the chart are minimum altitudes unless specified as otherwise (may be a line shown above and/or below the altitude). You don't have to be at every stepdown altitude, just as long as you are above each altitude. You have to be pretty high on a localizer to get a false glideslope (6 and 9 degrees? not sure). Besides the ILS is guaranteed out to 18nm. 35 degrees either side out to 10nm, 10 degrees out to 18nm.
02-18-2009 | 04:02 PM
#22
Gets Weekends Off
Joined: Oct 2008
Posts: 355
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From: OH CA - Retired
This reminds me of an instrument stage check I had. I flew the ILS exactly as published, and intercepted the glideslope at the published intercept altitude.
I passed the checkride, but afterwards my examiner asked me, "why wouldn't you have just intercepted the glideslope at 3,000 since that's where we were when we intercepted the localizer? (glide slope intercept was 2,700). I was confused as to the reason he was asking me... I think I said something like, "because the approach says the GS intercept altitude is 2,700." Then he went off about how you can intercept it from any altitude, and it doesn't say anywhere that you have to be at the GS intercept altitude.
I didn't want to argue with him, especially since I passed, but I thought he was incorrect.
I passed the checkride, but afterwards my examiner asked me, "why wouldn't you have just intercepted the glideslope at 3,000 since that's where we were when we intercepted the localizer? (glide slope intercept was 2,700). I was confused as to the reason he was asking me... I think I said something like, "because the approach says the GS intercept altitude is 2,700." Then he went off about how you can intercept it from any altitude, and it doesn't say anywhere that you have to be at the GS intercept altitude.
I didn't want to argue with him, especially since I passed, but I thought he was incorrect.
If the controller says, 'maintain at or above 2700 until established' by all means intercept at 4000' or whatever and follow the glideslope down. The fact remains: FAF is at a fixed geographic location at a fixed altitude. It doesn't move around.
02-18-2009 | 04:07 PM
#23
Prime Minister/Moderator
Joined: Jan 2006
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From: Engines Turn or People Swim
Be aware that some ILS's have coverage far exceeding the standard mins...if ATC clears you to intercept the LOC 25NM out, then that LOC is good to at least 25NM.
02-18-2009 | 04:10 PM
#24
Prime Minister/Moderator
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From: Engines Turn or People Swim
As you guys pointed out, the Glideslope does not guarantee altititude restrictions outside the FAF. Additionally, it may not be flight tested (you may get interferrence or abnormal indications). Don't confuse being told to join the localizer with an approach clearance. If you are arming the ILS to follow the localizer inbound to meet the alititude restrictions, I would say you are in violation because the aircraft isn't going to stop at the FAF altitude (remember, you weren't cleared the approach). At my company, we don't arm the ILS unless you are cleared the approach.
-Fatty
-Fatty
02-18-2009 | 04:20 PM
#25
C21H30O2
Joined: Mar 2008
Posts: 356
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From: L/R or workin' the panels!
I have to disagree to the timing. You do not fly an ILS to a time reference. Nor would starting the time at GS intercept work as this is typically prior to the LOC only FAF. If I am inside the FAF for an ILS and I lose GS, I am executing a missed approach. I was not cleared for the LOC approach. I did not brief a LOC approach. I will miss the approach, confer with ATC, and either return for the LOC only approach, an entirely different approach, or I will divert to my alternate. Of course if I were in an emergency situation, all bets are off and I might well consider a loc only approach. As for time, I call for time to start over the outer marker or FAF, not at GS intercept
02-18-2009 | 04:20 PM
#26
Airport Hobo
Joined: Apr 2007
Posts: 844
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That is not for the ILS, that is for the localizer beam. The GS has a different footprint, I think somebody said ten miles.
Be aware that some ILS's have coverage far exceeding the standard mins...if ATC clears you to intercept the LOC 25NM out, then that LOC is good to at least 25NM.
Be aware that some ILS's have coverage far exceeding the standard mins...if ATC clears you to intercept the LOC 25NM out, then that LOC is good to at least 25NM.
"The glide slope is normally usable to the distance of 10 NM. However, at some locations, the glide slope has been certified for an extended service volume which exceeds 10 NM." AIM 1-1-9(d3)
02-18-2009 | 04:39 PM
#27
Gets Weekends Off
Joined: Sep 2008
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From: CRJ-700 FO
02-18-2009 | 04:50 PM
#28
Prime Minister/Moderator
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From: Engines Turn or People Swim
02-18-2009 | 05:00 PM
#29
Gets Weekends Off
Joined: Apr 2007
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02-18-2009 | 05:06 PM
#30
Gets Weekends Off
Joined: Mar 2006
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From: SkyWest Capt.
Bottom line is always safety!!! Not only were you not cleared for the LOC Approach but winging the new approach during this critical phase is DEADLY!
What's that saying? "There are 2 types of pilots, old pilots and bold pilots, but there are no old bold pilots."
What's that saying? "There are 2 types of pilots, old pilots and bold pilots, but there are no old bold pilots."
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