TIPS FOR NOT BUSTING STEP DOWN ALTITUDES ?

[DCarlton]

This is going to sound like a novice question but... as per the subject line... does anyone have any swell tips for not busting step down altitudes on approaches (particularly those that say no lower than with the underline).  I don't have an autopilot that will couple with an approach; it only holds a heading bug.  I also don't have WAAS.  I'm considering adding a hundred feet to the published altitude and not going lower until I near the point where I can start the next step down.  Please hit me with your best shot / advice.  Thanks.  

 

 

[The Other Red Baron]

Personally I bug the altitude on the G5 and on our Avidyne 440 it shows the altitude for each segment of the approach.  If you don't have that equipment or similar... sticky note?  

 

[hais]

Not overshooting, or maintaining?

[201er]

You can self announce altitudes out loud every 500 or 1000 feet as you descend while reminding where you are going to. For example “5000, descending to 3000” or on the final leg, self announce minimums like 1500 descending to 720”

[eman1200]

Bug the aspen

[Skates97]

12 minutes ago, 201er said:

You can self announce altitudes out loud every 500 or 1000 feet as you descend while reminding where you are going to. For example “5000, descending to 3000” or on the final leg, self announce minimums like 1500 descending to 720”

I do this but when I am less than 500' to go to the altitude I will start saying how many feet I have left. So if I'm looking to stop at say 3,000 after passing through 3,500 I will say out loud "400' to go, 300' to go, etc..." It helps me with slowing the descent as I approach the altitude. 

That's assuming I don't have the GFC500 flying it for me. 

[DCarlton]

41 minutes ago, hais said:

Not overshooting, or maintaining?

I guess you would put it in the maintaining category.  Getting distracted by whatever (fiddling with NAV/COMM, etc) and dropping below.  

[Skates97]

Just now, DCarlton said:

I guess you would put it in the maintaining category.  Getting distracted by whatever (fiddling with NAV/COMM, etc) and dropping below.  

For maintaining when I had no autopilot I would give myself a 50-100' buffer like what you mentioned in your original post. Coming back from AZ into the LA basin even on VFR flight following I often got "descend and maintain" instructions. I would add that small buffer, never went below and never had ATC complain that I was 50-100' high. 

[PeteMc]

I used to just make sure that I did not do any other task as I was getting close to the altitude.  And if ATC started to give me anything other than a continued descent as I neared the altitude, I'd trim to a very slow descent.  I figured if I was close enough that I couldn't do both, they must think I'm close enough to bother me.  So I never cared if I almost leveled off 400 feet high and just continued down slowly.

(Now I just just plug in the Alt and turn on the AP to catch me if I'm writing down a new clearance.)

 

[takair]

If you are flying old school steam gauges, I use this gadget:  https://www.sportys.com/altitude-alert-indicator-2-7-8-in-dia.html

It is super simple and I use it religiously…even VFR. That way it becomes routine for when you really need it.  Has a 500’ and 100’ reminder if used properly. It may seem a little expensive for what it is, but lasts forever and worth it to help prevent a bust. 

[Ragsf15e]

Sometimes it helps to take a step back and see what’s causing you to bust altitudes on an approach because maintaining altitude/changing altitude is a basic ifr flying skill.  Typically I’ll find people misprioritizing secondary tasks (comm, checklist, etc) or being behind.  So what’s my recommendation? Make sure all your pre-approach checklists and approach brief are done before the IAF or before base in a radar pattern.  You will have to do your before landing checklist before the FAF but that’s it. I usually shoot for 1nm prior so I’m configured and stable starting the descent, but there are other techniques.  That checklist must be memorized and done expeditiously, but then checked (gear!).

Done right, you should have the approach plate on your lap, easy to read and be concentrating only on flying until the before landing check.  I do say each altitude leaving and the next one during my concentration.  Yes, there may be one or two radio calls in there and a switch to tower, but again, tower freq should already be already accessible/entered in a radio before you hit the IAF.  Practice comm so you do it second nature because your number 1 focus needs to be on flying.  If you’re leveling off and you ignore them for a few seconds, fine.

[201er]

2 hours ago, DCarlton said:

does anyone have any swell tips for not busting step down altitudes on approaches 

Come fly out in the NY airspace a few times. Bust your assigned altitude and ATC will read you a lesson you’ll never forget! Heard them nail a Cheyenne for only being a few hundred off.

[Danb]

I was a couple hundred feet high a few weeks ago around DC, they nicely gave me the  pressure reading since I was having difficulty dancing around clouds even Washington center gave be a block albeit a small on, 9,000 do not exceed 9,900. Good to know since summertime flying involves skirting various clouds. 

[DCarlton]

13 hours ago, Ragsf15e said:

Sometimes it helps to take a step back and see what’s causing you to bust altitudes on an approach because maintaining altitude/changing altitude is a basic ifr flying skill.  Typically I’ll find people misprioritizing secondary tasks (comm, checklist, etc) or being behind.  So what’s my recommendation? Make sure all your pre-approach checklists and approach brief are done before the IAF or before base in a radar pattern.  You will have to do your before landing checklist before the FAF but that’s it. I usually shoot for 1nm prior so I’m configured and stable starting the descent, but there are other techniques.  That checklist must be memorized and done expeditiously, but then checked (gear!).

Done right, you should have the approach plate on your lap, easy to read and be concentrating only on flying until the before landing check.  I do say each altitude leaving and the next one during my concentration.  Yes, there may be one or two radio calls in there and a switch to tower, but again, tower freq should already be already accessible/entered in a radio before you hit the IAF.  Practice comm so you do it second nature because your number 1 focus needs to be on flying.  If you’re leveling off and you ignore them for a few seconds, fine.

I'm actually trying to get through an IPC which is something I haven't had to do in years (blame COVID again).  Trying to tighten up and do better with the basics.  

[cbarry]

In my opinion, it is very easy to focus on the lateral track while on the approach and somewhat neglect the vertical track simply because the lateral guidance is the primary visual on the main section of a plate.   How many times have we heard about an accident whereby someone impacted an obstacle/terrain short of the runway while on approach, but were  on center line?  Verbal call outs may be of help:  “how’s my track, how’s my altitude, am I stabilized and configured for landing, am I ready to go missed…”

[midlifeflyer]

On 6/29/2022 at 9:56 PM, DCarlton said:

This is going to sound like a novice question but... as per the subject line... does anyone have any swell tips for not busting step down altitudes on approaches (particularly those that say no lower than with the underline).  I don't have an autopilot that will couple with an approach; it only holds a heading bug.  I also don't have WAAS.  I'm considering adding a hundred feet to the published altitude and not going lower until I near the point where I can start the next step down.  Please hit me with your best shot / advice.  Thanks.  

 

 

Back to Basics. IFR 101 - staying ahead of the airplane. That means always asking, "what's coming up next?" and having the  answer. ("What are the two most important things in aviation?" "The next two!")

Most if not all of us were exposed to the 5Ts during training. I'm not a fan of mnemonics but this is one of the few that's actually worth something. Not as a mantra to recite as we cross a fix - by then it's too late. For what it represents - a self briefing about the essentials about what comes next. 

Choose whatever method you want you want. A bunch of "Ts", self-talk, pen and paper. But create a SOP for what comes next. Here's a simple RNAV T. I'm flying  an old school GPS setup with an HSI that doesn't auto slew. I've just entered the GUSES OZOPE leg. I am at 3100 tracking 100°. I don't need any more brainpower for that. What I do need it for is, "when I get to OZOPE I will turn right 148°, turn my course indicator and heading bug to 148°, and descend to 2200'."  Say it again when closer. And just do it when prompted.

It's amazing how much brainpower it saves for other things.

 

Edited July 1, 2022 by midlifeflyer

[GeeBee]

Have you considered calculating a CDA?

 

[kortopates]

Have you considered calculating a CDA?
 

is that what i know as the DDA, Derived Decision altitude for continuous descent down to MDA without busting it by adding 10% of descent rate to MDA to begin level off?


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[midlifeflyer]

2 hours ago, kortopates said:

is that what i know as the DDA, Derived Decision altitude for continuous descent down to MDA without busting it by adding 10% of descent rate to MDA to begin level off?


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I'm guessing he's referring to what the FAA refers to as a CDFA, Continuous Final Descent Approach, the more stable alternative to dive and drive for approaches without vertical guidance (and kind of what "+V" is accomplishing in GPS boxes). 

[GeeBee]

Not entirely. If you have multiple step downs before the FAF, back up from that and create a constant decent from approach clearance to the FAF altitude. The max TERPS criteria is 500'/nm from the IAF to the FAF at a maximum, but most the time is 3 degrees or about 300'/nm. If you are at 90 knots GS you have to maintain 750 fpm for 500'/nm and 450 fpm for 300'/nm. If you have a 3 degree slope from the FAF you can just continue at 450 fpm. I run it backwards on the profile view and annotate the altitudes as a double check. So if I have a 1500' FAF and I get cleared for the approach at 7000' I start down 11 miles from the FAF holding 750 down and I will clear all restrictions under the most extreme conditions to make the FAF. While you are cleared to all minimum altitudes when cleared for the approach, there is nothing that says you have to be there right away unless you have mandatory crossing altitudes. The only altitude you don't want to be high is the FAF.

I have had a number of ferries with only one nav radio. Tuning cross radials can be a real PIA, so this method works when your workload is high.

[jaylw314]

When ATC assigns you an altitude, you have 200' of wiggle room either way, unless they say "at or above."

Once you're on the approach though (not the feeder routes but after the IAF), altitudes are usually "at or above".  That means no wiggle room below, but you have whatever you need above.  I can't think of a reason not to give yourself an extra 200' except for the final segment.

Also, remember it's psychologically hard to arrest your descent to the next altitude.  You're futzing around with the throttle at near idle and fine tuning it there, and after a while, it can be mentally difficult to jam it forward enough to arrest your descent.  It can feel like you're doing a go-around.  

Edited July 1, 2022 by jaylw314

[kortopates]

15 hours ago, jaylw314 said:

When ATC assigns you an altitude, you have 200' of wiggle room either way, unless they say "at or above."

Once you're on the approach though (not the feeder routes but after the IAF), altitudes are usually "at or above".  That means no wiggle room below, but you have whatever you need above.  I can't think of a reason not to give yourself an extra 200' except for the final segment.

Also, remember it's psychologically hard to arrest your descent to the next altitude.  You're futzing around with the throttle at near idle and fine tuning it there, and after a while, it can be mentally difficult to jam it forward enough to arrest your descent.  It can feel like you're doing a go-around.  

Actually by ACS (or formerly PCS) standards, from when you got your instrument rating or do an IPC today, you have to maintain -0' to +100' descending from FAF to the MAWP, so I encourage all my instrument pilots to add 50' to the MDA; especially on every circling approach where its easy to descend below MDA before you've met the criteria from 91.175 

[kortopates]

18 hours ago, GeeBee said:

Not entirely. If you have multiple step downs before the FAF, back up from that and create a constant decent from approach clearance to the FAF altitude. The max TERPS criteria is 500'/nm from the IAF to the FAF at a maximum, but most the time is 3 degrees or about 300'/nm. If you are at 90 knots GS you have to maintain 750 fpm for 500'/nm and 450 fpm for 300'/nm. If you have a 3 degree slope from the FAF you can just continue at 450 fpm. I run it backwards on the profile view and annotate the altitudes as a double check. So if I have a 1500' FAF and I get cleared for the approach at 7000' I start down 11 miles from the FAF holding 750 down and I will clear all restrictions under the most extreme conditions to make the FAF. While you are cleared to all minimum altitudes when cleared for the approach, there is nothing that says you have to be there right away unless you have mandatory crossing altitudes. The only altitude you don't want to be high is the FAF.

I have had a number of ferries with only one nav radio. Tuning cross radials can be a real PIA, so this method works when your workload is high.

But that is exactly what CDFA is all about as mentioned above by @midlifeflyer Its also the root of the FAA's original stabilized approach and the source for Garmin's +V. Its great to use +V on modern WAAS navigator, but not hard to do when the plate publishes a descent angle - where we can always look up the required FPM descent rate based on ground speed in the TPP Descent table to emulate what +V provides. Without a published descent angle it is significantly harder but still able to approximate as you well illustrate. I've always had at least some GPS with ETE to the next waypoint; which is much easier to judge something like I have 3 min to the next waypoint and 1800' to loose so I'll target at 600 FPM.  These days its really easy with the moving map showing us exactly where the plane will be at next bugged altitude based on current descent rate.

[GeeBee]

I think you mis-understand me. CDFA is for the final approach segment. Consider the name. "Continuous descent final approach".  I am talking the intermediate segment between the IAF and the FAF where you can often have several step downs and I believe that was the question  posed by the OP unless I was mistaken. Hit the FAF at charted altitude and do whatever you want, CDFA or dive and drive, not really important but all those cross radials or DME fixes on an intermediate segment can overwhelm someone, especially single nav and that is why I suggest the method I do. Knowing that 500'/nm will clear all those restrictions (and thus obstacles) and still have you arriving at the FAF on the charted altitude is a way to simplify the approach and keep the workload down. From there it is simply a matter to execute the final segment properly with whatever method you choose.

 

 

 

 

[Ragsf15e]

4 hours ago, kortopates said:

But that is exactly what CDFA is all about as mentioned above by @midlifeflyer Its also the root of the FAA's original stabilized approach and the source for Garmin's +V. Its great to use +V on modern WAAS navigator, but not hard to do when the plate publishes a descent angle - where we can always look up the required FPM descent rate based on ground speed in the TPP Descent table to emulate what +V provides. Without a published descent angle it is significantly harder but still able to approximate as you well illustrate. I've always had at least some GPS with ETE to the next waypoint; which is much easier to judge something like I have 3 min to the next waypoint and 1800' to loose so I'll target at 600 FPM.  These days its really easy with the moving map showing us exactly where the plane will be at next bugged altitude based on current descent rate.

I also teach folks the simple math to get the descent gradient when it’s not published.  Say a vdp on a non precision approach or multiple stepdowns such as this.  Some people like the math more than the charts.  I’m sure you guys knew these, just thought I’d chime in in case  someone likes the math.  A little practice and you can quickly do it in your head.

alt (in 100s) / nm = degrees

So 4000’/6nm = 40 / 6 = ~6.5 degrees 

usually 90kts gs (1.5nm/min) or 120kts gs (2nm/min), so

6.5 degrees x 1.5 nm/min = ~1000ft/min

for creating your own 3 degree vdp if none is published:

alt (in 100s) / 3 = VDP distance from runway

so 900’ MDA gives 900’ / 3 = 3nm