Instrument Approach Procedures

[BigTex]

I'm working on my instrument rating and was curious what every one's procedure is as they are approaching the FAF. What speed are you maintaining? When do you drop your gear? What about flaps? Do you have a target manifold pressure you pull back to as you start down?

Any kind of guidance you guys can share to get established and stablized on the glide path would be appreciated.

[Jerry 5TJ]

rather than give you my numbers, I suggest you go fly and work out your airplane's pitch and mp numbers for

• level flight, 120 mph, gear up
  
• level flight, 120 mph, gear down
  
• -500 fpm, 120 mph, gear up
  
• -500 fpm, 120 mph, gear down
  
• climb, 100 mph, gear up
  

and so forth.

If you know the pitch and mp for a given configuration, you can go to that combo and get predicted performance. Then, for example, when you cross the GS intercept at 120 mph, you can drop the gear, go to your proper pitch and mp, and presto, -500 fpm, a good first approximation for the glide path.

[201er]

I'm working on my instrument rating and was curious what every one's procedure is as they are approaching the FAF. What speed are you maintaining? When do you drop your gear? What about flaps? Do you have a target manifold pressure you pull back to as you start down?

All that sounds too complicated... I just fly the plane.

[jlunseth]

I agree with Big Tex here. You need to work out your numbers for your aircraft, and flying to the numbers is very important in instrument, particularly for procedures. But we can't tell you what your numbers are going to be.

Here is what I do. 120 kts. to the FAF. Then at the FAF its Time, Gear, Power, Tower, Lights, Lights, Lights. Translated, that means (1) start the timer for the time to the missed approach point, (2)drop the gear, (3) call the tower if you have not already, (4) make sure the gear light(s) show the gear is down, (5) turn on your landing light, and (6) turn on the runway lights if necessary. Dropping the gear at the FAF in my aircraft will yield 90 kts. in level flight without a change in power setting from those I use for 120 kts gear up, and it will require putting in takeoff flaps and dropping the power to around 18 something inches to keep the speed at 90 down the glideslope. I put in the full flaps or not, depending on the landing conditions such as how high I am above the runway (higher means more flaps needed to get down without gaining too much speed), what the wind conditions are (high, gusty winds call for partial or no flaps in my view), and how long the runway is (short field landing requires full flaps for the extra drag, plus maybe the speedbrakes).

Mind, my aircraft is a turbo so my 18 inches is not your 18 inches. The MAPA PPP puts out a pretty good book with starting numbers for every Mooney model, except not every plane flies to the ideal set of numbers. Their numbers for your aircraft are 2350 rpm's and 18", gear up, yields a level approach speed of 120 mph. The same setting gear down will yield a -500 fpm descent rate and 120 mph. Their book says you would get 105 mph for a descent speed with 2350 rpm's and 13 inches MP. You should use these as starting points and figure out your own aircraft's speeds at particular settings.

Then again, it depends on what you are going to be doing at the missed approach point. If you are going straight in then the above is the prescription, if you intend to do a circle to land, I never put in more than takeoff flaps. Don't want the drag of full flaps until landing.

[BigTex]

Thanks jlunseth! That's exactly what what I needed. Do you typically fly your approaches with flaps?

[John Pleisse]

Jlunseth is correct. You should have made a Power/Attitude/Configuration (PAC) chart with your CFII on the first day of your instrument work. Hours of BAI flying by those numbers should have been done before doing approaches.

At the FAF, everything is usually done, leaving only the tower/CTAF call and GUMP. Good luck with the checkride, hope you get it done soon.

[jlunseth]

Yes, after the FAF I put in takeoff flaps to control airspeed, partially for reasons that might apply to your aircraft and partially not. One, half flaps (takeoff setting) help control airspeed at 90 kts during the descent. Two, deploying flaps in my aircraft creates a strong pitching moment, so if I wait until I have the runway in sight and then decide I want full flaps for landing and put them all in at one time, I am going to be trimming heavily and pushing forward on the yoke during deployment. Putting half flaps in earlier just helps relieve some of that. Third, 231's generally are set very rich, and the engine "burbles" if I simply throttle back for the descent. One way of dealing with this is to lean the engine way out, but then I am not set up for a go around. Another is to add some resistance (drag) to the aircraft so I can power it up a little without adding speed, and then I can leave it rich without the burbling. Your NA aircraft is not likely to have an issue like that. Because of the burbling I tend to fly "stabilized approaches" somewhat like jets do, where I come down the glide path with some power on.

[Hank]

Gary--

In my C, I flew with someone to take notes, and wrote down MP/RPM combinations for the following:

• 90 knots, clean [mushy, I don't like it]
  
• 90 knots, Takeoff flaps, gear up, level
  
• 90 knots, Takeoff flaps, gear up, 500 fpm descent
  
• 90 knots, Takeoff flaps, gear down, level
  
• 90 knots, Takeoff flaps, gear down, 500 fpm descent
  

These formed my starting point, and 90 knots was a good training speed for me. It is not one that I get to fly real approaches at very often, at least outside the FAF.

I'm also a big fan of the MAPA PPP numbers approach. I like to be right at the top of the white arc by the IAF, and most approach altitudes around here are low [3000-4000 msl], so I generally reduce prop to 2300 RPM and set speed with throttle. Coming out of a power-on descent, it takes a couple or three miles to slow down; I often indicate 160+ mph at 500 fpm maintaining cruise MP and EGT during descent.

120-125 flaps up is a good speed for procedure turns, 6-mile legs on GPS T-patterns, etc. It will also help fit in with other traffic. But I learned at 105 mph [=90 knots], which helped my head not get left too far behind.

Somewhere before the IAF, set power for 90 knots and drop approach flaps. This may be two steps depending on your speed--reduce power, decelerate, drop flaps, add power to hold altitude.

You will need to do more experimenting to determine exactly when to drop the gear. For me, inbound at 105 mph with approach flaps, speed constant, altitude level, I have to drop the gear 1½ dots high to descend on the glide slope without touching anything else.

Most airports with approaches are long enough that approach flaps are all I need to land. At home, 3000' long with trees at the end, I set approach flaps on downwind and adjust as needed on final, so it's a normal attitude and view when I break out of the clouds/foggles and can see the runway. At that point, it's just a normal, everyday, VFR landing.

Note that with our vintage birds, you will become fluent in mph/knots [90 knots = 105 mph; 105 knots = 120 mph]. I also use "approach" flaps and "takeoff" flaps interchangeably, although the indicator is labeled "Up," "Takeoff" and "Down."

Learn the procedures at 90 knots for timing. Once you have the procedures down and can keep both needles centered, try flying a little faster, but be down to 90 knots by the FAF. Learn your power settings for clean, flaps only and flaps/gear for straight-and-level and for 500 fpm descent. Then you will be armed to really start learning!

Yes, I still keep those power setting notes on my kneeboard, and look at them every now and then.

[jetdriven]

All that sounds too complicated... I just fly the plane.

No kidding, Mike. I can tell you airlines do not cross the FAF and repeat "Time, turn, throttle, twist, tune, talk, carb heat-gas-undercarriage-mixture-props-pumps-seats-seatbelts-lights-three in the green"

[Txbyker]

I had an IFR instructor used to C172 speeds trying to get me to slow the Mooney down to 90 knots at the start of the procedure. I spent more time sloshing around trying to control the plane in slow flight than flying the procedure. After posting here and getting great feedback about speeds I now fly 120 knots in the procedure, procedure turns, and holds, then 90 knots at FAF and I get the 90 by lowering the gear and half flaps. I had a couple of instructors during my IFR and both wanted me to get configured well before FAF which results in a lot of slow flight.

[rbridges]

I'm like Hank. I shoot for 90 knots at the FAF. It lets me add flaps w/o having to kill speed. I've actually started doing 90-100 in the rest of the pattern while training. Early on, I was doing 120, and it's easy to gain/lose altitude when you're new at it.

Anyway, I'm still tweaking. Checkride should be in a month or two.

[Ksaunders]

I was always instructed to use as little flaps as possible to enable you to go missed more easily (positive rate of climb quicker). With the speed of our birds, I believe our approaches require a greater deal of skill, feel, and respect for precision than most others. Practice, practice, practice so it becomes second nature. Orient yourself to how your plane "Sounds" in all your configurations. I often can tell when my speed, prop, or flaps aren't right by knowing how it is supposed to "Sound". Landing in crazy weather with minimum flaps will really make you razor sharp behind the controls on those beautiful VFR - light wind down the runway days.

Your first true low ceiling approach by yourself will be a feeling like no other. You're worried all they way down but when you land safely at your destination, you look forward to that thrill over and over again. Kind-of like a really scary horror movie. Never comfortable during the bad parts but always exciting to look back on when it was really good......

[AndyFromCB]

20/2400 until FAF makes for easy 1

I had an IFR instructor used to C172 speeds trying to get me to slow the Mooney down to 90 knots at the start of the procedure. I spent more time sloshing around trying to control the plane in slow flight than flying the procedure. After posting here and getting great feedback about speeds I now fly 120 knots in the procedure, procedure turns, and holds, then 90 knots at FAF and I get the 90 by lowering the gear and half flaps. I had a couple of instructors during my IFR and both wanted me to get configured well before FAF which results in a lot of slow flight.

Yeah, this happens all the time with low time instructors who teach in a 172 and Cherokees. Doesn't work well in real world. A while ago at KMDW I was asked to maintain 160knots until FAF. It was either that or 20 minutes of holding and vectoring. This is where speed brakes are wonderful when you're sandwiched between two 737s. I'll always accept and then pop the speed brakes out at 1 mile before FAF and pull my throttle back to 20/2400.

I generally shoot for 120knots at 1 mile before FAF, which in my bird is usually 20/2400 or so, at FAF I drop the gear, throttle down to 18inches, half flaps, usually keeps me around 90knots.

I don't touch my prop or mixture either. In case of a go around, I just always remember to go right to left, everything forward.

What's a procedure turn? What's a timer? ;-)

[BigTex]

Thanks Hank... That helps a lot.

My flight instructor I'm using does have 500+ hours in Mooney's so hopefully that will help. That being said, we've been using his Cherokee 180 & C172 for much of my instruction and we're about to switch over to my Mooney to complete my IFR training. So I'll expect some of what txbyker mentioned. That's one of the reasons for this post is to be able to push back on techniques that have been found to not work well in Mooney's.

One thing I'll need to work through is when to drop flaps. With my C model, I have a 100 MPH limit so 105MPH/90kts will be too fast.

[Z W]

I did all of my instrument training in a 1968 C model. I've also got a bunch of time in a K model, which for instrument procedures, does not behave like the C. Take some of the advice above with a large grain of salt - it's good for later models, but not directly applicable to you. The guys with Js and Ks are operating a much larger, heavier, more powerful aircraft.

My preference in the C is to slow to 100 MPH at the IAF in a clean configuration. Sometimes that is not possible, I.E. if you are descending into the IAF or have a speed restriction, but it's my goal. Set up trim stabilized at 100 MPH clean, and you have a nicely responsive aircraft. This is usually 18-20 inches of MP. I drop the gear at the FAF, slow to 90 MPH, and add take-off flaps (2 pumps). At around 18 inches of MP, that will give you a nice 500 FPM descent. Adjust throttle as necessary to stay on glideslope. Leave the plane trimmed for 90 MPH. When you "break out" (either of clouds or of your foggles), adding full flaps will slow you to 80 MPH without any trim changes, and you're ready to land. If you don't break out and do a go-around, you only have 2 notches of flaps in, and the plane is already in a take-off climb configuration. Adding full power will put you into a Vy climb.

A few other nice tricks my CFI and I figured out:

If you're high coming into the IAF, put your gear down early. About 22" MP will level you off with gear down at 100 MPH, once you reach your target altitude.

The white arc can in fact be a limiting factor for you, as you've noticed. If you're high and fast, leave the flaps up, but put the gear down and pitch down for 115-120 MPH. You can get 1000 FPM descents that way very easy.

You may notice all of my advice is on how to get slowed down and descended. The plane is fast, and it's easy to get behind, especially while you're learning. Try to slow down and descend as early as possible. The speeds I've listed here are as slow as you can go without your controls getting mushy, and will help you learn, I hope. Running approaches at 120 MPH or more before the FAF will make your life much harder than it needs to be while you're learning.

Disclaimer: My C has a lot of speed mods. Yours may have slightly different MP settings. Only you can find the numbers for your plane. I also do all this at 2500 RPM, which still gives a good climb if you forget to push the prop in before short final (not that I've ever done that ).

Good luck, and keep with it. The rating is worth it, and made me a much better pilot.

[Hank]

Guess flap speed changed between 65 and 70! My Vfe is 125 mph, gear is 120. She handles pretty well at 90 knots/105 mph with approach flaps down, ~18"/2300 to stay level, drop the gear 1½ dots high and be on-slope by the time it centers.

105 with flaps up is a little less comfortable for me, but you are probably there in the pattern when VFR.

The day ATC asks me to maintain 160 knots is the day I will have no choice but answer "unable!" I have, though, been asked to reduce speed for traffic; more often, going into Class C, they will ask me to keep my speed up. That happened on my Instrument checkride as I was coming in on ILS, 8-9 miles out at 90 knots. I asked the DPE if I should speed up, he said something like "Sure, let's see what you can do." Flaps up, throttle forward, and down the glideslope at 140 mph; the difficult part was slowing back down to Vfe and not blowing the approach, but managed a nice touch-n-go, shot the missed and started on the next approach.

[Z W]

Guess flap speed changed between 65 and 70! My Vfe is 125 mph, gear is 120. She handles pretty well at 90 knots/105 mph with approach flaps down, ~18"/2300 to stay level, drop the gear 1½ dots high and be on-slope by the time it centers.

105 with flaps up is a little less comfortable for me, but you are probably there in the pattern when VFR.

I just looked, and my Vfe is also 125 MPH. I guess it changed between 65 and 68.

Also, my book clean stall speed is 67 MPH, or 58 KTS. At 105 MPH I'd say you have plenty of margin, and my plane even handles nicely at 100 MPH. But, whatever works for you is what matters.

[smccray]

Mind, my aircraft is a turbo so my 18 inches is not your 18 inches.

I've ready my Pelican's Perch and that doesn't make sense to me, but perhaps there's something I don't know. Is that a typo? If not, how is 18" in a turbo different than 18" in a NA? I know I could get high enough where my J won't produce 18" of MP and your turbo can still make near 100% power, but down low if the throttle is pulled back, isn't 18" the same regardless of the induction system?

[jetdriven]

I've ready my Pelican's Perch and that doesn't make sense to me, but perhaps there's something I don't know. Is that a typo? If not, how is 18" in a turbo different than 18" in a NA? I know I could get high enough where my J won't produce 18" of MP and your turbo can still make near 100% power, but down low if the throttle is pulled back, isn't 18" the same regardless of the induction system?

Its the same manifold pressure, but a TSIO-360 engine has low compression and needs 36" of manifold pressure to make rated 210 HP. So, at 23" of MP, the IO-360 Lycoming makes ~65% power and the TSIO makes ~50%.

Or another way to say it, is the percentage of maximum rated MP is one way to estimate HP. 30" is the most an IO-360 can develop, while a TSIO can make 39".

[Hank]

Dropping the gear at the FAF in my aircraft will yield 90 kts. in level flight without a change in power setting from those I use for 120 kts gear up, and it will require putting in takeoff flaps and dropping the power to around 18 something inches to keep the speed at 90 down the glideslope. . .

Mind, my aircraft is a turbo so my 18 inches is not your 18 inches. The MAPA PPP puts out a pretty good book with starting numbers for every Mooney model, except not every plane flies to the ideal set of numbers.

Amazing! I run up to the FAF at 90 knots with takeoff flaps already down, and dropping my gear 1½ dots high will send me down the glideslope still at 90 knots without touching anything else. I can't imagine losing 30 knots just from the gear, there's just not that much drag. Then you have to initiate a descent, too. Oh, wait, you have an extra door on each wheel . . .

I'm a firm believer in the KISS principle. Establish desired speed [90 knots at the FAF, or a little less to drop your flaps at 100 mph], drop gear to start descent. Maybe you can do it the other way around, establish level flight with your gear down and use flaps to control descent? Talk through it with your II, go fly some to see how it handles and what it feels like, find something that works for you and your plane, and write it down! That way you won't forget, and you can look at it if you don't do it for a while.

For my C:

90 knots clean, ~16"/2300

90 knots, approach flaps ~18"/2300

drop gear, descend glideslope at 90 knots

I forget the rest, it's on my kneeboard.

[FloridaMan]

I want to add; I've recently changed my own procedures as, after flying for hours in hard IMC I popped out into VFR and started my approach. When I advanced my prop to full-forward, my low vacuum light came on and my vacuum pump came apart on me. I'm not sure that RPM changes are worth doing if only moderate changes would get you safely into a missed approach.

[jetdriven]

I would venture if a 300 RPM change caused your vacuum pump to disintegrate then it was going to fail anyway.

the real risk (in a M20J anyways) is if you cram the throttle full open, then cram the prop full forward you will have an overspeed event. If it is done at high airspeed, it can exceed 3,000 RPM, which warrants a complete teardown. if the prop is already set full forward (it won't be at 2,700 RPM on an ILS or a visual approach, perhaps 2,100) it wont overspeed.

[moodychief]

In my 63 C model, gear down two pumps (manual) of flaps, 13" MP, trimmed for 85 mph, will keep you on the glide slope and ready for a missed. Maintain 85 mph all the way till over the end of the runway then slowly back the throttle off until your at idle, slight flair, hold off runway until it chirps near the aiming points.

[Gone]

Mine is like Moodychief, but with a manual gear E model.

[jlunseth]

No kidding, Mike. I can tell you airlines do not cross the FAF and repeat "Time, turn, throttle, twist, tune, talk, carb heat-gas-undercarriage-mixture-props-pumps-seats-seatbelts-lights-three in the green"

They have copilots and the copilots can be heads down and following checklists to the nut. We are by ourselves and don't have time to look at a checklist on an approach. Let them do their thing. We still need acronyms to make sure the gear goes down every time.