non-vectored NDB IAF

(Michael) wrote in message . com...
(C Kingsbury) wrote

approach. The outbound segment, if flown with positive course
guidance, gives you a chance to establish the crosswind component.
Fly it by DR, and you miss the chance.

Needle position and movement trend will indicate what you're dealing
with. At best I will grant you there is a theoretical reduction of
precision of measuring the x-wind component, but I suspect in most
cases the difference in the two approaches will be nugatory.

If it were unsafe
the procedure would not be allowed.

You truly need to disabuse yourself of that notion before it kills
you. Check out the VOR-B for LVJ sometime - a perfect example of how
you can fly an approach with equipment well within allowable
tolerances, to well within PTS standards, and still die.

Yes, and we allow people to drive 55MPH, despite the fact that some
people get killed doing just that.

I agree that final approach segments often demand higher precision
than what "the rules" require. My favorite is the ILS 5 to Lawrence,
MA, which ought to be called the cannonball run:

http://204.108.4.16/d-tpp/0409/00654I5.PDF

I'd be more interested however to find a case where a hold-style
procedure turn *clearly* increases risk versus the 45-180 PT. I
haven't seen one yet but it's a big planet, I suppose there's one out
there somewhere.

Best,
-cwk.

You have positive indication of ground track based on needle
position, direction of movement, and rate of movement.

Maybe, if the PT fix is based on navaid. but the information you
receive is imprecise and will vary with the distance from the navaid.
If the fix is an intersection, you don't have even that. A centered
needle is much easier to read.

Plus, you still run this risk with the procedure you've described,
when you go out and do the 45-180 PT.

You're only going outbound for a minute, in the fattest part of the
protected area. And the issue of a late turn over the holding fix is
missing.

I'll bet you five bucks the difference is minimal.

Well, no ****. The safety-conscious choices we make every day don't
matter most of the time. We put up with a bit of inconvenience to
give us an extra margin of safety for the extreme situations.

(C Kingsbury) wrote
Needle position and movement trend will indicate what you're dealing
with. At best I will grant you there is a theoretical reduction of
precision of measuring the x-wind component, but I suspect in most
cases the difference in the two approaches will be nugatory.

In most cases, you can just fly IMC without talking to anyone and it's
fine.

Yes, and we allow people to drive 55MPH, despite the fact that some
people get killed doing just that.

Which means that sometimes it's NOT safe to drive 55, even when that's
the speed limit.

I agree that final approach segments often demand higher precision
than what "the rules" require. My favorite is the ILS 5 to Lawrence,
MA, which ought to be called the cannonball run:

http://204.108.4.16/d-tpp/0409/00654I5.PDF

Clearly I am missing something here. Plese explain.

Michael

"C Kingsbury" wrote in message
om...
I agree that final approach segments often demand higher precision
than what "the rules" require. My favorite is the ILS 5 to Lawrence,
MA, which ought to be called the cannonball run:

http://204.108.4.16/d-tpp/0409/00654I5.PDF

Hm, that's one of my favorite approaches to practice in LIFR. Flying it to
PTS standards looks safe to me. Is there a hazard I'm failing to appreciate?

--Gary

"Gary Drescher" wrote in message news:9wn1d.296945$8_6.234657@attbi_s04...
"C Kingsbury" wrote in message
om...
I agree that final approach segments often demand higher precision
than what "the rules" require. My favorite is the ILS 5 to Lawrence,
MA, which ought to be called the cannonball run:

http://204.108.4.16/d-tpp/0409/00654I5.PDF

Hm, that's one of my favorite approaches to practice in LIFR. Flying it to
PTS standards looks safe to me. Is there a hazard I'm failing to appreciate?


No, not if flown properly. But, with the obstacles where they are, the
margin for error (particularly right around GRAPS where the
smokestacks are) is definitely reduced. I probably would not wait for
a full-scale right deflection before missing this approach if the
crosswinds were messing with my head.

It might be interesting sometime on a VFR day to fly this with the
localizer on its last dot (just barely not pegged) and also on the
last dot of the glideslope, just to see how much room that really
leaves you. Maybe I'll try it in Flight Simulator tonight just for
kicks.

Best,
-cwk.

(Michael) wrote in message . com...

(C Kingsbury) wrote
Needle position and movement trend will indicate what you're dealing
with. At best I will grant you there is a theoretical reduction of
precision of measuring the x-wind component, but I suspect in most
cases the difference in the two approaches will be nugatory.

In most cases, you can just fly IMC without talking to anyone and it's
fine.

Well, not around Boston you can't. But that's neither here nor there,
and my point remains. If you were to draw a bounding rectangle of the
airspace used by the two different procedure turn flightpaths, they
may not be identical, but I find it difficult to imagine a case where
the differences are actually significant from a perspective of utility
or safety. And again, it is clear beyond any argument that the full
procedure increases the pilot's workload, which in my view is among
the surest ways to reduce real safety.

At best, the full procedure might provide navigational precision of
5-10% on the inbound leg to the FAF, though I suspect this advnatage
washes out during the final approach segment, unless it is very short,
or nonexistent, as with a beacon on the field, in which case the
minimums are so high it makes little difference anyway.

My unqualified suspicion is that a lot more pilots, especially
lightplane single-pilot IFR ones, get into trouble with basic spatial
disorientation, than with modest navigational errors. Truly systematic
risk management looks at the effects each optimization has not just on
a particular variable, but on all variables.

Yes, and we allow people to drive 55MPH, despite the fact that some
people get killed doing just that.

Which means that sometimes it's NOT safe to drive 55, even when that's
the speed limit.

Yes, and it doesn't mean that we ought to lower it to 45 everywhere,
either. Your point that "I need to get into my head" that just because
the rules allow X doesn't mean X is safe smelled more than a bit
hyperbolic in this regard. To dismiss the rules completely because
there are one or two exceptions is no more intelligent than applying
them thoughtlessly in place of common sense.

Best,
-cwk.

"C Kingsbury" wrote in message
m...
"Gary Drescher" wrote in message
news:9wn1d.296945$8_6.234657@attbi_s04...
"C Kingsbury" wrote in message
om...
I agree that final approach segments often demand higher precision
than what "the rules" require. My favorite is the ILS 5 to Lawrence,
MA, which ought to be called the cannonball run:

http://204.108.4.16/d-tpp/0409/00654I5.PDF

Hm, that's one of my favorite approaches to practice in LIFR. Flying it
to
PTS standards looks safe to me. Is there a hazard I'm failing to
appreciate?


No, not if flown properly. But, with the obstacles where they are, the
margin for error (particularly right around GRAPS where the
smokestacks are) is definitely reduced.

True, but the obstacles are still well beyond both the horizontal and
vertical boundaries of the glideslope.

I probably would not wait for
a full-scale right deflection before missing this approach if the
crosswinds were messing with my head.

Yup, PTS standards call for no more than 3/4 deflection. I'd always go
missed in IMC if I were off by that much.

It might be interesting sometime on a VFR day to fly this with the
localizer on its last dot (just barely not pegged) and also on the
last dot of the glideslope, just to see how much room that really
leaves you. Maybe I'll try it in Flight Simulator tonight just for
kicks.

Cool, I'll give that a try too.

--Gary

"Gary Drescher" wrote
Yup, PTS standards call for no more than 3/4 deflection. I'd always go
missed in IMC if I were off by that much.

If you ever shoot the VOR-B at LVJ, half scale deflection (5-6
degrees) and a VOR that's off by 2 degrees (well within the acceptance
criteria) can be enough to kill you.

Michael

"Michael" wrote in message
om...
"Gary Drescher" wrote
Yup, PTS standards call for no more than 3/4 deflection. I'd always go
missed in IMC if I were off by that much.

If you ever shoot the VOR-B at LVJ, half scale deflection (5-6
degrees) and a VOR that's off by 2 degrees (well within the acceptance
criteria) can be enough to kill you.

Hm, the VOR could even be off by 6 degrees (for an in-air check) and still
be legal. In that case, even one dot of deflection could be lethal on that
approach.

--Gary

(Michael) wrote in message . com...
"Gary Drescher" wrote
Yup, PTS standards call for no more than 3/4 deflection. I'd always go
missed in IMC if I were off by that much.

If you ever shoot the VOR-B at LVJ, half scale deflection (5-6
degrees) and a VOR that's off by 2 degrees (well within the acceptance
criteria) can be enough to kill you.

Michael

I searched around in the NTSB database to see if any such accidents
had ever happened, and wasn't able to find any. Which means that I
either did the search incorrectly, or no one's luck has run out yet. I
agree that it's well within the range of possibility.

-cwk.