Clearances & Approaches

Another good debrief following a good flight lesson on tackling IFR clearances and approaches

94/05/12 22:59

From: E-Pilot To: DIPLOCAT Judith Bradt

Wind picking up, and up to 28knots at 3000. Probably going to be bumpy on the way down...no problem.

A good rule of thumb: if the wind velocity changes more than 2.5 knots per thousand feet, it is VERY LIKELY to be moderately turbulent. If the wind change is more than 4 knots per thousand feet, watch out for occasionally severe turbulence.

She reviewed the briefing that I'd gotten, and all of the approaches with me before we went. I liked that; Tom didn't do that with me. Maybe she was just trying to assess what stage I was at, as this was our first flight together. The briefing helped me to remember a couple of important things, and I learned a couple of new things.

I think that's the way a good instructor generally works, The instructor is trying to get you to think about what you're going to do – one way of keeping surprises of any sort to a minimum. It gives you a chance to discuss problems, procedures and/or guidelines. It helps prepare you for the lesson. By the same token, a post-flight briefing allows you to assess your own performance; allows the instructor to review what happened (or didn't), and to give you a sketch of the next lesson. Too many instructors skip this step.

I was reminded of the value of slowing the aircraft down a few miles BEFORE the IAF (and I thought of your reminder of how helpful it is to create TIME for oneself).

TIME WINDOWS -- not just time. A built-in hold, just like the Shuttle. It's not just dead time: it allows you the chance to get caught up and start thinking ahead. But call it what you like. Making time, if you prefer, though not many of my female students were ever guilty of making time with me. :)

There is a tendency on the part of many pilots to rush into an approach. You're right -- slowing down gives you the opportunity to practice thinking ahead: the reverse is true -- thinking ahead gives you the opportunity to slow down. But you're correct: slow down before your initial approach fix so that the airplane is stabilized, giving you the opportunity to fly the approach without a lot of power, airspeed and trim changes.

And she asked me how to identify the MAP on an ILS. Through discussion, I realized that you're there when you're at DH on the GS (another reason why BEING on the GS is rather important); the time is there as a backup if you have to go LOC only.

But you always start the time anyway, even though you're on an ILS approach, right? (You EVER know when the glide slope is going to crap out, do you?)

I came to realize the difference between "clearance on request" and "clearance available". I had thought that the former meant "ready when you want it", not "We've asked for it, and will get back to you". I had been saying "standby" to both, just to avoid getting a clearance spilled all over me. Now I know. I think this had been explained to me before, but it finally sunk in.

ATC, like most other mindless beaurcratic institutions, have only ONE way of doing things, ever. Every clearance -- repeat, EVERY -- clearnace you get will be in the same format.

C = Cleared to...
V = via...
M = maintain...
R = report...
S = squawk...

This is what they teach in air traffic controllers school. Exactly this. Makes no difference whether you're flying SFO-LHR or taxiing across a ramp.

If you know the format, AND you've taken the time to ask ATC on the telephone (BEFORE you filed your flight plan) what the preferred routing is, the only real mystery about your clearance is your altitude (which shouldn't be a big problem flying a light plane back east) and the transponder code.

Obviously, flying back east IFR is fraught with intersections and airways, changing MEAs and MOCAs and MVAs. But if you did your homework beforehand, you'll hear those magic words ("Cleared to... ...as filed") instead of the controller having to issue a full-route clearnace at 240 words per minute.

We got vectored around for the NDB, and had only a little turn to make to line up once we passed it. I was a little behind the game in getting slowed down, though, and a little slow in descending, too. I did the best job of holding the heading that I'd done in a long time -- though I was battling just a little bit of confusion on the "what heading do you have to hold/want to be on" question, even the mental gymnastics were much improved.

The REASON FOR a procedure turn is to allow you to slow to approach speed, and get the airplane into approach configuration! THINK ABOUT IT!!!

Altitude holding was not my strongest point on any of the three approaches; that needs to improve...but the work on headings was much better. On all three, Barbara said, I needed to be much more aggressive about getting down -- doing the 750 fpm descent to the step-down altitudes to give me as much time as I could get. The NDB approach finished high, and, as I slowed down late, I was over the airport a full 25 seconds before the time ran out, so I was reminded of how important that slow-down and descent really is.

Professionally, I get down to MDA immediately after passing the FAF or an ntermediate fix. This gives me time to stabilize the airplane as much as possible so that I can concentrate on my scan AND altitude management – thus giving me the best chance to be in a position to land if I happen to see the airport.

Even seeing the airport at MDA and a few miles out yet, I never descend below MDA until I am POSITIVE that I have proper vertical guidance to the touchdown zone. By this, I mean a VASI, PAPI or the equivalent. Nothing is worse that sneaking below the MDA with the field in sight, only to pop into a cloud at some altitude BELOW MDA. (Is there a big rock inside the cloud?
Who knows?)

One thing I calculate on a non-precision approach is something called a Visual Descent Point. The VDP (for short) is the last point from which you can make a normal landing (without excessive or extreme descent rates).

"High Performance IFR Flying" (Allen Schwab) gives an excellent discussion of the Visual Descent Point, marked on Jeppesen terminal charts by a "V" on the profile plan. I strongly suggest that you buy the book immediately and start reading! It's full of rules and hints from some of the old pros about IFR flying in general -- I re-read it at least once a year (in fact, my copy is falling apart).

Did an EXCELLENT PT, remembered to time...but got confused about whether I could descend before or after crossing the fix after the PT inbound (eek); a pointed question from Barbara made me realize what I was doing. Tracked the heading well inbound, but didn't get down as quickly as I ought to have.

Here's a point where it's easy to get killed.

In 1974 (?), a TWA crew descending into Dulles mistakenly thought that clearance for the approach meant that they could descend down to the initial approach altitude. In fact, they couldn't: beneath the approach corridor was a large mountain which happens to be the site of the President's nuclear war shelter (Mt. Weather). This ambiguity killed them, because they didn't remember to fly the minimum altitudes depicted on the approach plate.

On approaches, you MUST be familiar with the minimum altitude specified on the approach plate. PTs usually have a minimum altitude specified. Once established on your final approach course, inbound to the FAF, you MAY be able to descend -- look at the profile plan of the approach.

I developed the unusual habit -- on this flight -- of not repeating back my ATC instructions. This was odd, because I ALWAYS do that. I don't know why I changed. That's a good habit, and an easy one to recover.

Good. Whatever the cause, fix it. ALWAYS ALWAYS ALWAYS read back clearances. I discussed why before.

Got a good, predictable intercept for the ILS. Intercepted. Tracked that localizer within a dot and a half all the way down. Didn't do so well with the GS, but the LOC was SO much better! Your advice to keep a close watch on it was EXCELLENT and really helped.

With some practice -- and it will be difficult until you get a lot more experience -- you'll be able to fly your approach from the CDI instrument (where your G/S and LOC needles are located. But when you get into a good airplane, I STRONGLY suggest buying an ADI and HSI -- which have the localizer and glide slope needles incorporated into the gauge. The benefit here is that you can always see pitch, bank, yaw (there's a turn and slip indicator in the ADI), heading, and never lose sight of the glide slope and localizer needles.

I wish that you could fly with us for a few legs -- I'd put you up front with some headphones and show you just how easy this really is... once you have the right equipment. :) ;) :) Of course, we have our days when we earn our pay, and we get screwed up on approaches with crosswinds, headwinds, tailwinds and wind shears (and airplanes that won't fly straight unlessthey're flying sideways). I guess we're like everyone else.

Was too high on arrival at the airport; got down, was given incorrect circle-to-land instructions which I got corrected. Found that I was climbing from the DH back up towards circuit height, and then realized that I didn't need to make a VFR circuit (is that right?) even in VFR conditions if I am still on an IFR clearance.

Your clearance was for circle-to-land? This isn't really clear. If you had clearance to circle-to-land from the ILS (and the controller specifically knew that you wanted to fly the circle-to-land maneuver from the ILS), you should never have been at DH in the first place. As I understand it, you cannot go below the minimum altitude specified for the aircraft category in the circle-to-land maneuver. If you have to go down to DH in order to get the airport, you have no business doing a circling approach in the first place. IF you were approaching DH and got the airport in sight, technically -- for obstacle and terrain clearance -- you'd have to climb back to the circling altitude while maintaining the localizer course. In most cases, I'd call that a missed approach. (By the time you climbed back to the circling altitude while on the localizer, you would be out of position to do the circling maneuver : the circle-to-land radius is 1.1, 1.3, 1.5 miles for Cats A-C. You can work the math out for yourself, but there's no way – flying at 75 - 120 knots -- to climb 600-800 feet from DH (in landing configuration).

Overall, I felt much more in control of what was going on. I can see myself getting through this. I also strongly feel the need to keep on doing this -- often -- after I get the ticket. These skills are too hard won to let deteriorate.

Now you know why I have so much simulator time. Now you know why I have so much time just going out and practising approaches by myself. Remember this, Judy dearest: you will likely never be any sharper than the day you got your instrument rating -- unless you get dy-to-day instrument flying experience.

An instrument rating -- and your instrument currency -- is difficult and expensive to maintain. THE FARs requiring 6 hours of instrument time and 6 approaches to minimums is JUST a minimum requirement. To be really good at it requires continuing practice. It is astute of you to make this observation...

I hereby anoint you with the power to be my backup conscience on this issue and remind me to get back up in the air as often as possible, in case I forget how much effort all this has taken.

Like Van Cliburn is reported to have said, "If I don't practice one day, I know it. If I don't practice for a week, everyone else knows it." Keep your name out of the newspapers, Judy. Get checked out in an airplane you can use to fly during winter months so that you can do some actual IFR practice of approaches. Be your own conscience. Like your dentist and gynecologist, visit your local CFI regularly.

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