ILS pattern speeds

[snippyfsxer]

I'm not a real world pilot, only a fake one, so I pose this question to those who are:

Using a generic Twin Engine GA aircraft:
Using a generic pattern that has a procedure turn and a LOM:
What speeds (Vso reference is fine) should I aim for as I approach the IAF?
As I enter the procedure turn?
Approaching the FAF?
Final approach to threshold?
general flap deployments (i.e first notch, at the turn outbound, or whatever)?

I know this is an extraordinarily general question, but there must be some rule of thumb.

[Mobius]

I have no twin experience, but in 172s, I usually fly everything after the IAF and until the last few hundred feet at 90 kts because it's easy to figure out time to distance calcs in my head (@90kts: 1.5nm per 1 min), and MAP timing is done at 30kt intervals starting at 60 kts (up to 180 kts), so you don't have to try to figure out the timing if you're flying at something in-between.

[Splinter562]

I'm in nearly the same camp as Mobius for light GA. I fly most of the approach at cruise speed. Full approaches are a nearly a cross country in and of themselves, so it's best to setup for a cruise configuration.

When I slow down to an approach speed depends on the approach I'm flying. For approaches with lots of tight maneuvering, like many VOR approaches for small airports, I'll slow down at the Initial Approach Fix (IAF). For approaches built for jets at bigger airport, I'll wait until I'm approaching the Final Approach Fix (FAF) to slow down. Sometimes, on ILSs with miles between the FAF and the runway, I'll keep the speed up until I'm on short final.

So, for as far as a "rule-of-thumb" for approach speeds:
Light single - 90-100 KTS
Light multi - 100-120 KTS

Here's my general order of operations:
IAF - Cruise or slowing to approach speed
Procedure turn - Cruise or approach speed
FAF - Approach speed, gear down
Runway environment in sight (or short final) - Slowing to normal final approach speed, extend flaps to desired setting for landing when inside white arc.

[snippyfsxer]

Excellent!  Thanks for the info.  I'm happy to say thats how I've been doing it, but I wasn't sure

[flaminghotsauce]

I go the opposite direction. My instructors used to ask me why I didn't slow down more?

When doing instrument approaches with procedure turns, trying to stay inside the ten mile radius with a twin at cruise isn't logical. This is a safety issue, as that ten miles is your protection at the altitude on the approach.

I had the most trouble with NDB approaches carrying too much speed. We had one approach where we had four miles between the final approach fix and the runway, and had to lose, I forget, 1800' ? before reaching the runway. Slow down! In the 172, 90 kts as mentioned above makes it easier to time the approach. I use that as my max speed in that airplane!

[BSW727]

I was taught at that speed as well in the 172 & Mooney.

Sometimes faster at larger airports or they won't let you in if they can't sequence you during high traffic (big aluminum tube) periods.

The first time I was told to "keep your speed up, 737 in trail", I thought WTF?

[Mobius]

I was taught at that speed as well in the 172 & Mooney.

Sometimes faster at larger airports or they won't let you in if they can't sequence you during high traffic (big aluminum tube) periods.

The first time I was told to "keep your speed up, 737 in trail", I thought WTF?

I've had that too.  I rode right seat on a flight to O'Hare a few months ago and our cruise speed on the way down was 135 kts and we were asked to maintain 160 kts on the approach because everyone else was flying the approach at 200 kts.  We got 1 mile out and dumped all gear and flaps to get down to our final approach speed.  That was interesting.

[Andy Hughes]

Twins are different.
You need to land the twin at the speed that you can go-around on ONE ENGINE.
That's usually called "blue line", it's Vyse - Vy single engine, and it's usually (almost always) faster than Vy.
in a C310 for example, Vy is like 90kts, but blue line is 120.
You end up almost driving the plane onto the runway and not cutting power until the wheels touch.

[olderndirt]

Twins are different.
You need to land the twin at the speed that you can go-around on ONE ENGINE.
That's usually called "blue line", it's Vyse - Vy single engine, and it's usually (almost always) faster than Vy.
in a C310 for example, Vy is like 90kts, but blue line is 120.
You end up almost driving the plane onto the runway and not cutting power until the wheels touch.

Things have changed since 1970 - when I got my MEL.