Instrument Approach Speeds

Inverted25

Inverted25

Well-Known Member
So this debate came up the other day. Obviously everyone has their own way of doing it. When teaching students in say a airplane like a Cessna 172, what speed do you have them shoot an instrument approach? I always had my students slow the airplane down while they were intercepting the final approach course and shoot the approach at 90 knots. I do this for a few reasons. One it I beleive that it makes it easier to actually shoot the approach at the slower speed. Secondly I like 90 knots because if they shoot a ILS and break out at mins, 200 ft above the runway, they will be able to slow down and land.

Now to the counter argument. They argue that you should teach them to approach at 120 knots for a few reasons. First the airplane will be at a lower angle of attack so it will pick up less ice if they are in icing conditions. Secondly they feel it better prepares them to fly bigger and faster airplanes

My arguement with shooting the approach faster is mainly I dont want my students busting out the clouds on a ILS at 200 ft at 120 knots. Good luck slowing down and landing when the normal approach speed is 70 knots.

What do you guys think?
 
IMHO (and this is not a textbook answer that I know of), you should be configured for landing at approach speed prior to the FAF. Trying to fly a stabilized approach from a good start is pretty hard to do if you are constantly correcting for self induced errors.....ie change in airspeed (and or pitch/power combo) which will result from changing configuration, and even in a fixed gear aircraft, simply slowing down will change the required VSI as well as your wind corrected heading. Not variables I want to introduce while I am pointing my nose at the ground down to mins. Where you actually slow and/or configure is probably aircraft dependent, but I would say as a generality, you want to be in your landing configuration when you commence the final portion of your approach. VMC, yeah have at weird speed changes and other stuff, but when my pink butt is counting on me flying a controlled stabilized approach, I don't want to make my job any harder than it has to be. For reference, while shooting an approach to the carrier, we dirty up at 8 NM, and are completely configured and on speed by around 6 NM. We don't start the final descent (analogous to the FAF) until 3 NM, while flying at around 130-140 kts indicated in landing configuration/on speed. I don't think there is another flying community out there that demands more precision from an approach or from landing than us, save maybe the space shuttle, so that might not be a bad mentality to carry forward into other parts of aviation. Not saying to slow up 5 miles from the FAF in a 55-80 kt airplane, but what I am saying is that the same idea can be applied. Whatever I am flying, I want a good minute or so trimmed up and stabilized prior to trying to fly the needles and the precision they require.
 
When I was learning instruments I learned everything at 90kts. I feel it made it easier to learn. On the checkride the check pilot said something along the lines of "The world doesn't fly at 90kts" but since it wasn't anything technically wrong I still passed. When I was doing my commercial I flew approaches faster because my instructor stressed that people paying money would want you to get there faster. But as far as learning instruments I still believe learning at 90kts makes it easier and it's not wrong. If you have a student that could pick it up faster then I'd probably have them fly faster. Then again I'm just working on my CFI now.
 
120 knots seems like it would take an awful lot of power for the approach in most single engine trainers.
 
You should shoot the approach at the airspeed the airplane was designed for. 120kts seems insanely high for a 172. I fly my tprop at that speed, and we cruise at 300kts not.. .well 120.
You don't fly your 172 at 1500ft pattern do you? Well the turbine world does. But that's a terrible argument. Fly the airplane like that particular airplane is supposed to be flown. Adjust with the new airplane, don't try to turn a 172 into something it's not. In fact whoever is teaching to fly a 172 like a king air is a bad instructor IMO. There will be plenty of time to learn the king air when you actually fly it.
 
ERAU taught (while I was there) 100 knots in the 172. I thought it was too fast, but complied with their company policy when I was in courses there.
 
Learn at the speed appropriate to the airplane. In a 172, I'd say 75-85 inside the FAF with the flaps at 20. Slower with full flaps. Once one is proficient with the procedures you can introduce different speeds and configurations necessary for mixing it up with faster traffic.

Often when flying to airports with that faster traffic, there are longer runways, so faster, clean approaches shouldn't present a problem for landing.

Bottom line, learn/teach at a speed appropriate for the airplane, and do variations later.

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I dont currently teach instrument students, but I would favor teaching them to be adaptable and therefore fly both slower and faster approaches... after they gain initial proficiency with basic instrument flight and they understand procedures.

When I first learned, everything was tied to specific numbers... fly the approach at X power setting which will yield Y airspeed and Z rate of descent, etc.... great stuff when starting, but as proficiency is gained I think an instrument pilot should be able to adapt to the aircraft, type of approach (an ILS to an 11,000' runway vs a non-precision timed VOR approach to a small country airport), ATC requests (maintain max speed, vectors leaving them high and fast, etc), environmental concerns (icing exposure)... I was never taught anything other than the initial profiles and had to start "thinking" after I got my ticket.
 
Inverted25 said:
So this debate came up the other day. Obviously everyone has their own way of doing it. When teaching students in say a airplane like a Cessna 172, what speed do you have them shoot an instrument approach? I always had my students slow the airplane down while they were intercepting the final approach course and shoot the approach at 90 knots. I do this for a few reasons. One it I beleive that it makes it easier to actually shoot the approach at the slower speed. Secondly I like 90 knots because if they shoot a ILS and break out at mins, 200 ft above the runway, they will be able to slow down and land.
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That's what I used and was taught in the 172, until it was time to seriously consider getting in—at which point I'd slow it to 80-75. Time to look, decide, and act.

Now to the counter argument. They argue that you should teach them to approach at 120 knots for a few reasons. First the airplane will be at a lower angle of attack so it will pick up less ice if they are in icing conditions. Secondly they feel it better prepares them to fly bigger and faster airplanes
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Oh god...


Your 172 isn't a jet; don't fly it like one. The time to learn how to fly larger/heavier equipment will come.

I can understand the ice accretion argument but can't see doing EVERY approach at that speed.
My arguement with shooting the approach faster is mainly I dont want my students busting out the clouds on a ILS at 200 ft at 120 knots. Good luck slowing down and landing when the normal approach speed is 70 knots.
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I suppose you could do it, but the question is "why would you?"

What do you guys think?
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When I was doing repeat practice approaches in the 172, I'd do it at 90-100 knots. As stated, slowing down if it's "seriously for real here."

In the Twin Bonanza, 90-95 works.

In the Brasilia, I like to have things settled down to steady-state (no configuration changes) at the final approach fix. That's a profile requirement by the company, who pays me to do it that way.
 
Why in the world would you fly a Cat A airplane at Cat B/C airspeeds and use the higher minimums?????? One of my favorite tests on an IPC or for a pilot "ready for their instrument check ride" is to give them an approach where Cat B/C/D is N/A and watch what they do. If they fly at 91 KIAS or greater it is a bust. As per the Aircraft Approach Categories table in the IAPs:
"An aircraft shall fit in only one category. However, if it is necessary to operate at a speed in excess of the upper limit of the speed range for an aircraft's category, the minimums for the category for that speed shall be used." My emphasis.
 
Blackhawk said:
Why in the world would you fly a Cat A airplane at Cat B/C airspeeds and use the higher minimums?????? One of my favorite tests on an IPC or for a pilot "ready for their instrument check ride" is to give them an approach where Cat B/C/D is N/A and watch what they do. If they fly at 91 KIAS or greater it is a bust. As per the Aircraft Approach Categories table in the IAPs:
"An aircraft shall fit in only one category. However, if it is necessary to operate at a speed in excess of the upper limit of the speed range for an aircraft's category, the minimums for the category for that speed shall be used." My emphasis.
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I could make a good argument for argument's sake you're wrong. (I whole heatedly agree with you though)
 
I ask my students to shoot approaches at different airspeeds. Generally, in a C172 and DA42 we fly at 100 kts or I will tell them otherwise. It lets me know if they can handle some new things before I teach partial panel ops.

In the complex multi I like to teach configuration leading up to FAC and then airspeed a couple miles before TOD. Generally we do 21"/2400 RPM on base then 18" on the last vector to final then flaps to approach once on FAC then slow/increase to approach speed and finally TOD gear down(generally without a power change). If they can learn to use the different amounts of drag on different segments of the approach it seems they have a much better understanding of how to handle the airplane in other phases of flight.
 
90.

There is a good reason to teach 120 - the need (instruction) to keep speed up in an environment where there is other, faster traffic.

It's actually pretty easy to fly an ILS in a 172 at 120. And a stabilized approach is not an issue. ILS runways are made to accept much heavier, faster aircraft; there's more than enough runway and there's more than enough dirtiness in a 172 to get stabilized for landing in plenty of time - we're talking instrument pilots, not solo students.

But that 120 is the same as 100 or 110 or 80 or 70. We need to be prepared to mix with other traffic (I actually once got an instruction to slow down when flying a 172 at 90 on an ILS!). But dealing with variations is not a good reason to teach the variation as the standard.

Secondly they feel it better prepares them to fly bigger and faster airplanes
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Complete nonsense. What doe that CFI do, teach his C152 primary students to set up for 103 kts on final because he might someday fly a King Air?
 
z987k said:
I could make a good argument for argument's sake you're wrong. (I whole heatedly agree with you though)
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I think the confusion on this comes from a change to the wording. It use to read "...should..." but at some point was changed to "...shall...". "Shall" has normally been interpreted as an imperative.
Also from the Instrument Procedures Handbook:
"Pilots are responsible for determining if a higher approach category applies. If a faster approach speed is used that places the aircraft in a higher approach category, the minimums for the appropriate higher category must be used."

Again, "must" is an imperative.
 
While I teach 90, I do feel instrument students should be trained fly high speed approaches as well. As Mark pointed out there are times where it will be necessary. I remember a check hauling company flew 210's into KATL. They were pretty much required to fly high speed ILS approaches at that airport in order to fit into the flow.
 
For normal every day jive 90kts is a good speed to start at. For trainers it's a comfortable speed and your FAF to MAP times are easy to figure if your still timing it. Like others have said I'd show them how to fly the ILS at high speed. I'm sure a 172 can easily do 120 on approach to 200' and land within the TDZ safely.

This wouldn't be a normal procedure obviously but if your ever on fire or need to beat weather that's moving in, or carrying ice then have at it. Who cares about approach categories when it's an emergency situation. I'd be glad I had the instruction on how to handle and execute if ever needed.


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It depends on the model of 172... Mainly, flap limitations. In a 172, when you dump a lot of flap quick (using them as speed brakes) and aren't ready to push or guarding the trim you could easily balloon back up into the clouds....

Earlier than a P, 100-90, no flap. 85 is just too slow, but 5 kts goes away quick when you reduce the power an hold a bit of back pressure and trim. Also, at 85 the pitch change isn't as drastic.

P or later 100-110, 10 flap. Helps with the slow down, and initial amount of trim is already set.

Remember, were talking about an airplane that is NOT ready to land until under 50 KTS

Yeah, try 120 on the ILS 16R into VNY with the 3.9 slope and a 30kt tailwind....
 
The bad examples point out why someone should practice a bit with different airplanes they fly and find out how long it takes and what configuration is best to slow down if hauling arse down a glideslope. Do it a few times and you know, then it's a simple known configuration change to be in a known-good position to land without doing anything unexpected or dramatic.
 
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