non-vectored NDB IAF

[Nicholas Kliewer]

I was practicing the following NDB-A approach
at F46 (Rockwall -- East of Dallas, TX)

http://204.108.4.16/d-tpp/0409/06323NA.PDF

And asked for the full approach.

Without GPS or vectors what's the best way to get
turned around outbound if I am on a heading of 090
to intercept the NDB IAF? How about if I am
approaching the IAF at a 90 degree intercept angle?

Thanks all,
-Nick

[Roy Smith]

In article >,
Nicholas Kliewer > wrote:

> I was practicing the following NDB-A approach
> at F46 (Rockwall -- East of Dallas, TX)
>
> http://204.108.4.16/d-tpp/0409/06323NA.PDF
>
> And asked for the full approach.
>
> Without GPS or vectors what's the best way to get
> turned around outbound if I am on a heading of 090
> to intercept the NDB IAF?

I would wait until I had station passage at PQF (i.e. the needle
flipped) then begin a right turn to a heading of 060. I would hold 060
heading until you had intercepted the 027 bearing from the NDB, i.e.
until the needle was about 30 degrees off the centerline. Then I would
turn right to 207 (plus or minus a WAG at the required wind direction)
and start tracking outbound for about a minute, then begin my procedure
turn.

When I was all done with the approach, I would tear the damned ADF out
of the panel and install a GPS. :-)

[Jarema]

Nicholas Kliewer wrote:

> I was practicing the following NDB-A approach
> at F46 (Rockwall -- East of Dallas, TX)
>
> http://204.108.4.16/d-tpp/0409/06323NA.PDF
>
> And asked for the full approach.
>
> Without GPS or vectors what's the best way to get
> turned around outbound if I am on a heading of 090
> to intercept the NDB IAF? How about if I am
> approaching the IAF at a 90 degree intercept angle?

Hello.

I would pass NDB than turn right for outbound heading (207) and fly for
a while (let say 2 minutes). After this time make 180 turn for inbound
heading. Probably you will have to turn right (becouse you will be east
of course) but it depends on conditions (eg. wind). Before every
procedure turn look where you are!

I hope it help. If I am wrong- please correct me.

Jarema

[Paul Tomblin]

In a previous article, Roy Smith > said:
>In article >,
> Nicholas Kliewer > wrote:
>> http://204.108.4.16/d-tpp/0409/06323NA.PDF
>> turned around outbound if I am on a heading of 090
>> to intercept the NDB IAF?
>
>I would wait until I had station passage at PQF (i.e. the needle
>flipped) then begin a right turn to a heading of 060. I would hold 060
>heading until you had intercepted the 027 bearing from the NDB, i.e.

060? Huh? I think 240 would work better.




--
Paul Tomblin > http://xcski.com/blogs/pt/
Some days violence is just a nice quick solution to a problem that
would need thought, planning and actual work to do justice to.
-- Wayne Pascoe

[Jeremy Lew]

"Roy Smith" > wrote in message
...
> In article >,
> Nicholas Kliewer > wrote:
> I would wait until I had station passage at PQF (i.e. the needle
> flipped) then begin a right turn to a heading of 060. I would hold 060
> heading until you had intercepted the 027 bearing from the NDB, i.e.
> until the needle was about 30 degrees off the centerline. Then I would
> turn right to 207 (plus or minus a WAG at the required wind direction)
> and start tracking outbound for about a minute, then begin my procedure
> turn.

Are you seriously suggesting a 330 degree right turn? I'm fairly new at this
IFR stuff, but that seems nuts to me. Why not just turn right to 237 and
wait until you cross the 207 bearing FROM, then proceed outbound at 207 for
another minute?

[Bob Gardner]

Let me join the fray. There is no need whatsoever to intercept the 207
bearing from the NDB and track it outbound, so how about (either heading 090
or 90 degrees to the FAC) turning to 207 plus/minus a wind guess at station
passage, timing a couple of minutes or more, depending on the wind...making
an extended holding pattern, IOW, and turning back to an intercept heading
somewhere between 340 and 000? Makes sense to me. Only those pilots who are
wedded to the 45-180 course reversal would do that much maneuvering.

Understand that if the winds are strong enough to make wind drift a real
problem, with an 8.5 mile final approach segment it might be better to go
somewhere else and forget about Rockwall for the time being.

Bob Gardner

"Nicholas Kliewer" > wrote in message
...
> I was practicing the following NDB-A approach
> at F46 (Rockwall -- East of Dallas, TX)
>
> http://204.108.4.16/d-tpp/0409/06323NA.PDF
>
> And asked for the full approach.
>
> Without GPS or vectors what's the best way to get
> turned around outbound if I am on a heading of 090
> to intercept the NDB IAF? How about if I am
> approaching the IAF at a 90 degree intercept angle?
>
> Thanks all,
> -Nick

[Andrew Sarangan]

Nicholas Kliewer > wrote in news:413F6E02.5FBFA90
@hotmale.com:

> I was practicing the following NDB-A approach
> at F46 (Rockwall -- East of Dallas, TX)
>
> http://204.108.4.16/d-tpp/0409/06323NA.PDF
>
> And asked for the full approach.
>
> Without GPS or vectors what's the best way to get
> turned around outbound if I am on a heading of 090
> to intercept the NDB IAF? How about if I am
> approaching the IAF at a 90 degree intercept angle?
>
> Thanks all,
> -Nick


Do the turning-around in two steps instead of one big step.

After station passage, turn to the outbound heading of 207. Then look at
the needle indication and turn again intercept the course. A 30 deg
intercept will require a heading of 237. Since you are maneuvering on the
protected side of the holding pattern, you should be fine.

[Ron Rosenfeld]

On Wed, 08 Sep 2004 15:39:30 -0500, Nicholas Kliewer >
wrote:

>I was practicing the following NDB-A approach
>at F46 (Rockwall -- East of Dallas, TX)
>
>http://204.108.4.16/d-tpp/0409/06323NA.PDF
>
>And asked for the full approach.
>
>Without GPS or vectors what's the best way to get
>turned around outbound if I am on a heading of 090
>to intercept the NDB IAF? How about if I am
>approaching the IAF at a 90 degree intercept angle?
>
>Thanks all,
>-Nick

Cross the NDB on a heading of 090°. Turn right to 207° +/- WCA and proceed
outbound parallel to and SE of the FAC. Descend to 2000'. After one to
two minutes, depending on wind, turn inbound to intercept the final
approach course, and complete the approach.

You will have done a racetrack type course reversal on the proper side of
the FAC.




--ron

[Roy Smith]

In article >,
"Jeremy Lew" > wrote:

> "Roy Smith" > wrote in message
> ...
> > In article >,
> > Nicholas Kliewer > wrote:
> > I would wait until I had station passage at PQF (i.e. the needle
> > flipped) then begin a right turn to a heading of 060. I would hold 060
> > heading until you had intercepted the 027 bearing from the NDB, i.e.
> > until the needle was about 30 degrees off the centerline. Then I would
> > turn right to 207 (plus or minus a WAG at the required wind direction)
> > and start tracking outbound for about a minute, then begin my procedure
> > turn.
>
> Are you seriously suggesting a 330 degree right turn? I'm fairly new at this
> IFR stuff, but that seems nuts to me. Why not just turn right to 237 and
> wait until you cross the 207 bearing FROM, then proceed outbound at 207 for
> another minute?

Du-oh! Of course not, I got my headings off by 180 degrees. Right turn
to 240, to intercept the 207 bearing. Sorry about that.

[C Kingsbury]

"Bob Gardner" > wrote in message >...

> Let me join the fray. There is no need whatsoever to intercept the 207
> bearing from the NDB and track it outbound, so how about (either heading 090
> or 90 degrees to the FAC) turning to 207 plus/minus a wind guess at station
> passage, timing a couple of minutes or more, depending on the wind...making
> an extended holding pattern, IOW, and turning back to an intercept heading
> somewhere between 340 and 000? Makes sense to me. Only those pilots who are
> wedded to the 45-180 course reversal would do that much maneuvering.

I'll second that, especially as there's a published hold just like
that right there, so you should be in protected airspace at all times.

I was taught that the above method is entirely kosher according to the
rules of the road, and as it requires a lot less turning, there's a
lot less work and chance to screw up or get disoriented.

Best,
-cwk.

[Julian Scarfe]

"Bob Gardner" > wrote in message
...
> Let me join the fray. There is no need whatsoever to intercept the 207
> bearing from the NDB and track it outbound, so how about (either heading
090
> or 90 degrees to the FAC) turning to 207 plus/minus a wind guess at
station
> passage, timing a couple of minutes or more, depending on the
wind...making
> an extended holding pattern, IOW, and turning back to an intercept heading
> somewhere between 340 and 000? Makes sense to me. Only those pilots who
are
> wedded to the 45-180 course reversal would do that much maneuvering.

Is an "extended holding pattern" a permitted course reversal for any
approach, or does the hold have to be charted (as it is at PQF, presumably
for the missed approach)?

Julin Scarfe

[Ron Rosenfeld]

On Thu, 09 Sep 2004 06:24:25 GMT, "Julian Scarfe" >
wrote:

>Is an "extended holding pattern" a permitted course reversal for any
>approach, or does the hold have to be charted (as it is at PQF, presumably
>for the missed approach)?

In the US, on NACO charts, unless the hold is depicted by a procedure
track, the pilot can fly it any which way (AIM5-4-9 a 1).

On Jepp charts the principal is the same, although the conventions are a
bit different.

On the approach in question, the PT is depicted by a 'barb'. The type of
turn would be considered a 'racetrack'.

==================
AIM 5-4-9
a ...
1. On U.S. Government charts, a barbed arrow indicates the
direction or side of the outbound course on which the procedure turn is
made. Headings are provided for course reversal using the 45 degree type
procedure turn. However, the point at which the turn may be commenced and
the type and rate of turn is left to the discretion of the pilot. Some of
the options are the 45 degree procedure turn, the racetrack pattern, the
tear-drop procedure turn, or the 80 degree « 260 degree course reversal.
Some procedure turns are specified by procedural track. These turns must be
flown exactly as depicted.
====================
--ron

[Julian Scarfe]

> On Thu, 09 Sep 2004 06:24:25 GMT, "Julian Scarfe" >
> wrote:
>
> >Is an "extended holding pattern" a permitted course reversal for any
> >approach, or does the hold have to be charted (as it is at PQF,
presumably
> >for the missed approach)?

"Ron Rosenfeld" > wrote in message
...
>
> In the US, on NACO charts, unless the hold is depicted by a procedure
> track, the pilot can fly it any which way (AIM5-4-9 a 1).

Thanks Ron.

In the UK (and in general under ICAO PANS-OPS rules), course reversals must
be flown as depicted, and they're usually base turns. In particular, in
PANS-OPS there's an admonition that the airspace protected where procedure
turns and base turns are depicted may not be sufficient for racetracks and
holding patterns, though in the UK it is rare for terrain to be an issue at
IAF altitudes.

Julian Scarfe

[Ron Rosenfeld]

On Thu, 09 Sep 2004 12:25:15 GMT, "Julian Scarfe" >
wrote:

>In the UK (and in general under ICAO PANS-OPS rules), course reversals must
>be flown as depicted, and they're usually base turns.

In the US, we usually call those "tear drops". If a tear drop is depicted,
either on the NACO or on the Jepp charts, then it must be flown as
depicted, also.

>In particular, in
>PANS-OPS there's an admonition that the airspace protected where procedure
>turns and base turns are depicted may not be sufficient for racetracks and
>holding patterns, though in the UK it is rare for terrain to be an issue at
>IAF altitudes.

That's true in the US, also. And the "depicted" turns, whether they be
base turns or other depictions are generally used when limited space is
available. This could be due either to terrain or to traffic.

But the majority of our procedure turns are not depicted in this manner.
The limitation for the non-depicted type course reversals is that they be
carried out on the proper side of the final course, and that they be
accomplished within some defined mileage of the point at which one can
begin the PT -- usually ten miles, but if only Category A a/c are using the
field, it could be five miles. And if larger a/c have to be accomodated,
it could be fifteen miles.


--ron

[Greg Esres]

<<Only those pilots who are wedded to the 45-180 course reversal would
do that much maneuvering.>>

Or those who are wedded to positive course guidance on the outbound,
as opposed to ded reckoning. ;-)

[C Kingsbury]

Greg Esres > wrote in message >...
> <<Only those pilots who are wedded to the 45-180 course reversal would
> do that much maneuvering.>>
>
> Or those who are wedded to positive course guidance on the outbound,
> as opposed to ded reckoning. ;-)

You can't be serious ;)

I think you're just being cheeky but in any case here's a detailed
breakdown of the two procedures.

This is no more ded reckoning than you do on *every* published holding
pattern.

Your only needs navigationally are to (i) keep the course to your
right and (ii) to not get too far away from it. If the needle stays on
the right side of your tail and doesn't start moving forward (as in
towards the nose; ideally it will fall back a little as you head
outbound) both of these are totally assured.

Except for pedantry's sake I do not see any benefit to being dead-on
the 207 magnetic bearing on the outbound segment. If it were unsafe
the procedure would not be allowed.

Further, let's look at the turns each procedure requires:

"Hold-style" PT:
1. upon station passage turn right to outbound heading, 90->207 =
117deg
2. after a minute or so outbound as needed, turn right to intercept
the bearing, 207->342 =~ 140deg
3. turn to 027 upon bearing intercept, 342->027 = 45deg

3 turns totaling 300 degrees, all in the same direction too. Pretty
simple and hard to screw up.

"Pedantic" PT:
1. upon station passage turn right to intercept the 207 magnetic
bearing from the beacon. Don't be too fast though or you'll fly right
through it. 90->240 = 150deg
2. Upon bearing intercept turn left 30 deg to establish
3. after appropriate amount of time turn left 45 for the procedure
turn
4. thence right 180 degrees to re-intercept the inbound 027 bearing to
the beacon
5. upon intercept right 45 degrees to establish yourself on the 027
bearing to the beacon

Total 5 turns, two changes of direction, total 450 degrees. Plus,
depending on how much you goof around intercepting the outbound
bearing in steps 1 and 2, you have a great opportunity to leave the
beacon and its protected airspace well behind you.

Now add a 090@20 wind to this and tell me which one of these offers a
better guarantee of not screwing the pooch completely.

Cheers,
-cwk.

[[email protected]]

Turn outbound for the procedure turn in what seems to be the shortest
turn. There is a whole lot of protected airspace for the procedure
turn. Sometimes there will be a note to not descend to the procedure
turn altitude until established outbound. If there is no such note you
can begin descent to the procedure turn altitude as you begin the turn
outbound.

Nicholas Kliewer wrote:
> I was practicing the following NDB-A approach
> at F46 (Rockwall -- East of Dallas, TX)
>
> http://204.108.4.16/d-tpp/0409/06323NA.PDF
>
> And asked for the full approach.
>
> Without GPS or vectors what's the best way to get
> turned around outbound if I am on a heading of 090
> to intercept the NDB IAF? How about if I am
> approaching the IAF at a 90 degree intercept angle?
>
> Thanks all,
> -Nick

[Michael]

(C Kingsbury) wrote
> This is no more ded reckoning than you do on *every* published holding
> pattern.

True enough, but most of the time your only purpose in the hold is to
stay in one place for a while. Here, you're about to shoot an NDB
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.

> Except for pedantry's sake I do not see any benefit to being dead-on
> the 207 magnetic bearing on the outbound segment.

Well, if you're confident enough of your skills to not want the extra
chance to establish the crosswind component, and confident enough that
wou will roll out established inbound - go for it.

> 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.

Michael

[Greg Esres]

<<This is no more ded reckoning than you do on *every* published
holding pattern.>>

Bob suggested flying outbound for two minutes or more, so there is
over twice as much ded reckoning as on a standard hold.

A late turn, with a wicked crosswind component could push you
uncomfortably close to the edge of the protected area.

The standard PT keeps you right in the middle of the protected area
most of the time.

[C Kingsbury]

Greg Esres > wrote in message >...
> <<This is no more ded reckoning than you do on *every* published
> holding pattern.>>
>
> Bob suggested flying outbound for two minutes or more, so there is
> over twice as much ded reckoning as on a standard hold.

Actually my point is that neither this form of PT or an NDB hold are
in fact "ded reckoning." You have positive indication of ground track
based on needle position, direction of movement, and rate of movement.

> A late turn, with a wicked crosswind component could push you
> uncomfortably close to the edge of the protected area.

The needle will tell you what's going on during the outbound leg.
Plus, you still run this risk with the procedure you've described,
when you go out and do the 45-180 PT.

I will grant that there is a slight advantage to your procedure in
this one area, but I still think it's outweighed by the significantly
increased opportunities it offers to screw up in other ways.

> The standard PT keeps you right in the middle of the protected area
> most of the time.

Try flying this with a handheld GPS ground track turned on, fly it
twice each way. I'll bet you five bucks the difference is minimal.

Best,
-cwk.

[C Kingsbury]

(Michael) wrote in message >...
> (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.

[Greg Esres]

<<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.

[Michael]

(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

[Gary Drescher]

"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

[C Kingsbury]

"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.

[C Kingsbury]

(Michael) wrote in message >...

> (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.

[Gary Drescher]

"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

[Michael]

"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

[Gary Drescher]

"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

[C Kingsbury]

(Michael) wrote in message >...
> "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.

[Gary Drescher]

"C Kingsbury" > wrote in message
m...
> 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.

I tried it on FS2004. At full deflection, you certainly come close to a
smokestack, but you don't hit it. (Of course, the FS2004 scenery shouldn't
be trusted for real-world purposes, though it looks correct here.)

--Gary

[Michael]

(C Kingsbury) wrote
> 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.

I wonder how many of those CFIT accidents where the aircraft was
inexplicably off the FAC are actually a result of this.

I also don't think it's such a big deal anymore, because nobody I know
flies IFR without GPS, be it IFR certified or not.

Michael

[Gary Drescher]

"Michael" > wrote in message
m...
> I wonder how many of those CFIT accidents where the aircraft was
> inexplicably off the FAC are actually a result of this.
>
> I also don't think it's such a big deal anymore, because nobody I know
> flies IFR without GPS, be it IFR certified or not.

I do. There's no GPS in most of the IFR planes I rent (but they do have VFR
LORAN).

--Gary

[Michael]

"Gary Drescher" > wrote
> 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.

Quite true. The scary part is I almost killed myself and a student
that way. We had a lesson one morning, I called for a briefing, and
there were two airports reporting IFR conditions. LVJ was the closer
one, so we went there (I'm a big believer in training in actual
whenever possible, even if it adds time to the lesson - owners tend to
be OK with that since they're just paying for gas) and the only
approaches were VOR and GPS. The plane had no GPS, but the VOR was
fine.

We got about 30 minutes of actual on the way out, but then the weather
started breaking up. Still, by the time we broke out we were being
vectored to the FAC so I had the student put the hood on and continue.

He was doing a fairly credible job of it (the air was bumpy) meaning
he was well within PTS standards at all times. And so I sat there and
watched as he performed an approach that should have been fine - and I
saw us head for a tower. Had we been in IMC, there is an excellent
chance I would not be here.

After this, we performed a VOR check in the air on this VOR. The VOR
showed 5 degrees off. In other words, it was legal. We later checked
it in the air on another VOR. On that one, it showed 2 degrees off.

Michael