Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

Descend to MSA when "cleared approach"

Tech Log The very best in practical technical discussion on the web

Descend to MSA when "cleared approach"

Old 7th Sep 2016, 16:25
  #41 (permalink)  
 
Join Date: Apr 2009
Location: On the Beach
Posts: 3,233
oggers:

...my point is that because of that accident you are reminded to "maintain [assigned altitude] until established" when you are vectored to intercept the localiser. As opposed to assuming you will maintain it. This thread has convinced me that is a wise move by the FAA.
Indeed it was. The circumstances of the accident were more complex. The flight was coming from KIND. Washington Center cleared the flight to intercept the AML 301 radial some 35 miles from the airport and descend to 7,000. Then the center handed the flight off to Dulles Approach Control. The Approach Controller issued no lower altitude. He simply cleared the flight for the approach. Had they maintained 7,000 to the final approach fix they would have been about 5,000 feet too high. So, they were caught with a lousy clearance and a deficient approach chart.
aterpster is offline  
Old 10th Sep 2016, 03:00
  #42 (permalink)  
 
Join Date: Nov 2004
Location: bkk
Posts: 285
PLATFORM ALTITUDE.
If you are from UK or have worked in a company run by Brits you know instantly what "platform altitude" means.For the rest of us it is the initial published altitude on an instrument approach chart from where you commence your final descent at the FAF......typically for a sea level airport its something around the 2-3000 feet amsl area with QNH set.Peter.
piratepete is offline  
Old 4th Oct 2016, 13:50
  #43 (permalink)  
 
Join Date: Jul 2002
Location: The Single European Sky
Posts: 22
Looks like ICAO are trying to tackle it too.

This is in the amendment to Doc4444 effective next month:
8.9.4.2 When clearance for the approach is issued, aircraft shall maintain last assigned level until intercepting the specified or nominal glide path of the approach procedure. If ATC requires an aircraft to intercept the glide path at a level other than a level flight segment depicted on the instrument approach chart, ATC shall instruct the pilot to maintain the particular level until established on the glide path.
Plus a whole heap of stuff about climb/descent on SIDs/STARs.
pukeko is offline  
Old 4th Oct 2016, 16:12
  #44 (permalink)  
 
Join Date: Jun 2000
Location: last time I looked I was still here.
Posts: 4,510
Considering that, perhaps, the majority of pilots reading this do not have English as their first language I think they should make text as simple as possible and avoid questions. (a comment I made to some previous airlines where many crew notices needed 3 or 4 readings, and even then.......?)

The first sentence is an instruction to the crew. Maintain last assigned level by ATC. Clear. It doesn't matter if this is above the 'level flight chart segment' or not.

The 2nd sentence is an instruction to ATC. If they want the crew to maintain a level above the 'level flight chart segment' they have to instruct the crew. i.e. back up the SOP of the 1st sentence.

I suppose it could be called belt & braces; but when reading both sentences it make me wonder if I misunderstood the first one. That seemed as clear as could be.

Am I missing something?
RAT 5 is offline  
Old 4th Oct 2016, 18:43
  #45 (permalink)  
 
Join Date: May 2013
Location: Canada
Posts: 63
On vectors

When we are on vectors in Canada and cleared for an approach we can descend as described in the TC AIM quote posted previously.


If we are on vectors below MSA but at or above min vectoring altitude, we will normally get "On interception, cleared the straight in ILS XX approach."


I can't recall being on vectors and subsequently being "cleared out of controlled airspace for an IFR approach", but getting this app clnc off of a PPos Dct GPS enroute phase happens quite regularly at the uncontrolled fields up here.


Maybe the hugemongous holes in our radar coverage is the reason for the flexibility in our rules?


Viper 7 is offline  
Old 5th Oct 2016, 04:10
  #46 (permalink)  
 
Join Date: Oct 2009
Location: Prescott, AZ
Posts: 35
In the past it was noise abatement.


I haven't flown for many years but in my day it was not uncommon to receive a vector that would take you to the OM along with a clearance - cleared for the approach. The last assigned altitude was well above the glide slope intercept altitude at the OM.
The controllers procedures did not allow descent below that last assigned altitude due to noise abatement in the area of the vector. Thus the pilots had to start a descent before intercepting the approach path in order to make a normal descent to the airport. This was most prevalent in NY, Washington and other high density areas.


It was still common to receive these types of clearances when I retired in 1998.
N1EPR is offline  
Old 12th Nov 2016, 12:59
  #47 (permalink)  
 
Join Date: Dec 2011
Location: Madrid
Posts: 7
Hello everybody,
First in Spain we apply EASA and ICAO rules, maybe in FAA or in UK has something slightly different.

FROM ICAO, clear for the app means that you are clear for both lateral a vertical navigation but you can start your descend if you are within 5 degrees or half of the max LOC desvistion (I'm saying this by memory so the wording could be different).

Also, if the ATC want you to maintain the altitude way after the loc interception they should say it like they do it Le Bourget, they clear you for the "LOC only" maintain the altitude until you are advised by the ATC that you can start your final descent.

If you are expecting to achieve the LOC too high you should request descend to the ATC.

This is my humble opinion because I haven't seen anything written telling you that you can leave the altitude assign by the ATC until established.
ALBATROS is offline  
Old 13th Nov 2016, 12:48
  #48 (permalink)  
 
Join Date: Jan 2008
Location: Sunny
Posts: 20
Originally Posted by aterpster View Post
The FAA discontinued sectorization of MSAs on RNAV charts.
If you mean that the MSA circle is never split into pieces, with different altitudes in the different pieces, you are mistaken. [Maybe you meant something else?]

Have a look at the RNAV approaches at the following airports and you'll see what I mean: PASH, PAIW, PAOM, PAGL, PFEL. These are just a few examples.
pa12 pilot is offline  
Old 13th Nov 2016, 13:18
  #49 (permalink)  
 
Join Date: Nov 2005
Location: Zulu Time Zone
Posts: 653
pa12 pilot, having just checked every RNAV app on that list there were only two that had MSAs and both of those were non-sectorized like aterpster said. All the others had TAAs. You know there's a difference right?
oggers is offline  
Old 13th Nov 2016, 13:19
  #50 (permalink)  
 
Join Date: Jan 2008
Location: Sunny
Posts: 20
Let me back up, because I was reading "MSA" and my brain was thinking "TAA."

Here's what the AIM says:

5. Altitudes published within the TAA replace the MSA altitude. However, unlike MSA altitudes the TAA altitudes are operationally usable altitudes.

And:

(a) An ATC clearance direct to an IAF or to the IF/IAF without an approach clearance does not authorize a pilot to descend to a lower TAA altitude.

And:

(b) Once cleared for the approach, pilots may descend in the TAA sector to the minimum altitude depicted within the defined area/subdivision, unless instructed otherwise by air traffic control.

Forgive me for having taken us down a detour.
pa12 pilot is offline  
Old 13th Nov 2016, 13:19
  #51 (permalink)  
 
Join Date: Apr 2009
Location: On the Beach
Posts: 3,233
TAAs and FAA MSAs are two quite different criterion.
aterpster is offline  
Old 13th Nov 2016, 13:24
  #52 (permalink)  
 
Join Date: Nov 2005
Location: Zulu Time Zone
Posts: 653
Forgive me for having taken us down a detour.
Ok thanks for clarifying.
oggers is offline  
Old 13th Nov 2016, 13:53
  #53 (permalink)  
 
Join Date: Apr 2009
Location: On the Beach
Posts: 3,233
Here is an example of a useless MSA on an FAA RNAV approach:
Attached Images
File Type: jpg
F70.jpg (333.9 KB, 25 views)
aterpster is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.