NDB Holds

[Alan Burke]

Hi,

I'm studying for my IR and having some trouble in calculating the outbound
times. Has anyone got any easy way of calculating the times.

[Jose[_1_]]

> I'm studying for my IR and having some trouble in calculating the outbound
> times. Has anyone got any easy way of calculating the times.

What I do in real life is to time the inbound, and then whatever the
error is on the inbound, I apply it to the outbound the opposite way.
It may take a couple of turns to get it right since the relationship is
not linear, but for small wind speeds compared to aircraft speeds, it
seems to work well enough.

Time outbound one minute. Time inbound. Say it's forty seconds.
That's twenty seconds too little, so next time go outbound a minute and
twenty seconds. Time the inbound. Say it's fifty-five seconds. Next
time go outbound another five seconds - that is, go out a minute and
twenty-five seconds. Iterate until happy.

If interested, the actual formula is:
(where v is velocity, t is time, and d is distance)

v = d / t
or
d = v t

The two distances (along the inbound course) will be the same, to first
order, so set them equal.

d = (v1)(t1) = (v2)(t2)

Rewrite v1 as v+w and v2 as v-w (where w is wind speed)
Rewrite t1 as t and t2 as t+d
(where d is the difference between one minute (t1) and the inbound.)

We end up with
(2w)/(v-w) = d

If I didn't mess anything up. (this doesn't take the crosswind's effect
on the half circle sizes into effect).

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

[Mark Hansen]

On 10/27/06 14:35, Alan Burke wrote:
> Hi,
>
> I'm studying for my IR and having some trouble in calculating the outbound
> times. Has anyone got any easy way of calculating the times.
>
>

Alan,

See Jose's answer for the timing. All I wanted to add was that you
should guestimate the crosswind correction before entering the hold,
and apply this on the first leg. Otherwise, the crosswind may really
mess with the timings.

Remember to adjust for the crosswind on the inbound leg as well ;-)

I would have guessed your question would have been more like "how do
you tell when to *begin* timing on the outbound leg".

.... perhaps that's still coming ;-)

I hope that you'll post more about your IR adventures. I sure would like
to read about them and participate in answering questions, etc.

Best Regards,

--
Mark Hansen, PP-ASEL, Instrument Airplane
Cal Aggie Flying Farmers
Sacramento, CA

[Sam Spade]

Mark Hansen wrote:

> On 10/27/06 14:35, Alan Burke wrote:
>
>>Hi,
>>
>>I'm studying for my IR and having some trouble in calculating the outbound
>>times. Has anyone got any easy way of calculating the times.
>>

Keep in mind, as you progress with this, that the "rule" is to not
exceed one minute inbound to the NDB.

[Alan Burke]

Thanks guys for the response. What I suppose I am asking if how do you work
out the times (pre-planning) of the hold. I.e if you know the wind direction
and speed for the hold, I've worked out the single drift and in my notes it
says to work out the timings use 75% of the head / tail wind factor.

This is where I get stuck. How do you work that out??



"Sam Spade" > wrote in message
...
> Mark Hansen wrote:
>
>> On 10/27/06 14:35, Alan Burke wrote:
>>
>>>Hi,
>>>
>>>I'm studying for my IR and having some trouble in calculating the
>>>outbound times. Has anyone got any easy way of calculating the times.
>
> Keep in mind, as you progress with this, that the "rule" is to not exceed
> one minute inbound to the NDB.

[Roy Smith]

In article >,
"Alan Burke" > wrote:

> Thanks guys for the response. What I suppose I am asking if how do you work
> out the times (pre-planning) of the hold. I.e if you know the wind direction
> and speed for the hold, I've worked out the single drift and in my notes it
> says to work out the timings use 75% of the head / tail wind factor.
>
> This is where I get stuck. How do you work that out??

Don't try to "work it out". Your primary job is to fly the airplane, not
work out complex geometry problems.

As you're approaching the hold, take a WAG (Wild Assed Guess) at wind
strength. In most common trainers, you'll be holding at about 90 kts. A
really big headwind component on your outbound leg would be 30 kts, making
your outbound groundspeed 60, and your inbound groundspeed 120 (double your
outbound).

So, that's pretty much an upper limit, and gives you your first WAG: with a
really honking headwind outbound, fly the outbound leg for 2 minutes.
Estimate down from there: with a moderate headwind outbound, try 1.5
minutes. With little or no wind, try 1 minute. With a moderate tailwind
outbound, try 50 seconds, and with a really honking tailwind outbound, try
40 seconds. If you're trying to get things any more accurate than that,
you're doing way too much work.

It's better to fly your first outbound leg a little bit long rather than a
little bit short. If you under-estimate how long to fly outbound, by the
time you complete your inbound turn, you can be almost on top of the NDB
and not have enough time to re-intercept the inbound bearing before you
reach station passage. When that happens, you tend to just keep getting
more and more confused and lost.

But, the real way to do NBD holds is to tear that piece of crap ADF out of
the panel and train in a GPS-equipped airplane. If your school doesn't
have GPS in their trainers, find another school.

[Thomas Borchert]

Alan,

> my notes it
> says to work out the timings use 75% of the head / tail wind factor.
>

Hmm. Why not 100 percent? The way I would do it is to figure out the
percentage the head/tail wind is of my IAS (TAS, if you want to get
precise). Then, I would correct 1 minute by that percentage. From your
notes, your supposed to take 75 percent of that percentage.

In reality, this takes way too much brain power away from controlling
the aircraft. Make intelligent guesses. E.g. your holding speed is 90
knots, your wind component is an estimated 10 knots, so you try a 10
seconds correction.

--
Thomas Borchert (EDDH)

[Sam Spade]

Thomas Borchert wrote:
> Alan,
>
>
>>my notes it
>>says to work out the timings use 75% of the head / tail wind factor.
>>
>
>
> Hmm. Why not 100 percent? The way I would do it is to figure out the
> percentage the head/tail wind is of my IAS (TAS, if you want to get
> precise). Then, I would correct 1 minute by that percentage. From your
> notes, your supposed to take 75 percent of that percentage.
>
> In reality, this takes way too much brain power away from controlling
> the aircraft. Make intelligent guesses. E.g. your holding speed is 90
> knots, your wind component is an estimated 10 knots, so you try a 10
> seconds correction.
>

At 90 knots it all is just b.s. to try to placate some anal instructor
or check airperson. The holding pattern protected airspace is designed
for a jet aircraft.

[Jose[_1_]]

> At 90 knots it all is just b.s. to try to placate some anal instructor or check airperson. The holding pattern protected airspace is designed for a jet aircraft.

I wouldn't go that far. We are also building good habits and attitudes
for the future. One day we may be flying jet aircraft, who knows? The
attitudes you start out with are likely to be the attitudes you end up
with, and the skills you learn from day one are the ones that come back
to you in an emergency.

However, yes, there is plenty of room in the hold for a spam can.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

[Mark Hansen]

On 10/28/06 08:24, Sam Spade wrote:
> Thomas Borchert wrote:
>> Alan,
>>
>>
>>>my notes it
>>>says to work out the timings use 75% of the head / tail wind factor.
>>>
>>
>>
>> Hmm. Why not 100 percent? The way I would do it is to figure out the
>> percentage the head/tail wind is of my IAS (TAS, if you want to get
>> precise). Then, I would correct 1 minute by that percentage. From your
>> notes, your supposed to take 75 percent of that percentage.
>>
>> In reality, this takes way too much brain power away from controlling
>> the aircraft. Make intelligent guesses. E.g. your holding speed is 90
>> knots, your wind component is an estimated 10 knots, so you try a 10
>> seconds correction.
>>
>
> At 90 knots it all is just b.s. to try to placate some anal instructor
> or check airperson. The holding pattern protected airspace is designed
> for a jet aircraft.

Exactly. I think if you show the inspector that you:

1. consider the crosswind when taking a guess at your outbound and
inbound headings;
2. consider the head/tail wind when taking a guess at your initial
outbound timing;
3. make a reasonable adjustment to your second outbound timing after
seeing what your first inbound leg time was.

he will be impressed.

Note that in all three cases, all that will matter is that you make
the correction in the right direction; the *amount* of the correction
won't matter to them.

I know that during training, I would like to go around the holds over
and over, making minor corrections to try to get the time and heading
to work out perfectly - my instructor would just get bored and make
us move on ;-)


--
Mark Hansen, PP-ASEL, Instrument Airplane
Cal Aggie Flying Farmers
Sacramento, CA

[Sam Spade]

Jose wrote:
>> At 90 knots it all is just b.s. to try to placate some anal instructor
>> or check airperson. The holding pattern protected airspace is
>> designed for a jet aircraft.
>
>
> I wouldn't go that far. We are also building good habits and attitudes
> for the future. One day we may be flying jet aircraft, who knows? The
> attitudes you start out with are likely to be the attitudes you end up
> with, and the skills you learn from day one are the ones that come back
> to you in an emergency.

I have posted almost exactly the same comments here in the past. Of
course, you are correct. The "recommended" entries are really mandatory
for jet aircraft operating at the max permitted speeds. And, so forth.
>
> However, yes, there is plenty of room in the hold for a spam can.

Exactly.

[Roy Smith]

Jose > wrote:
> > At 90 knots it all is just b.s. to try to placate some anal instructor or
> > check airperson. The holding pattern protected airspace is designed for a
> > jet aircraft.
>
> I wouldn't go that far. We are also building good habits and attitudes
> for the future.

Right. And a good attitude is to not get bogged down in minutia like
calculating outbound leg times for NDB holds when there's more important
stuff to be thinking about.

What's the weather doing? What's my fuel situation, i.e. how long can I
let ATC park me here before I need to head to my alternate? What is my
best alternate given the current situation? Can I review the approach
plate one more time to make sure I really understand the procedure.

[Sam Spade]

Roy Smith wrote:
> Jose > wrote:
>
>>>At 90 knots it all is just b.s. to try to placate some anal instructor or
>>>check airperson. The holding pattern protected airspace is designed for a
>>>jet aircraft.
>>
>>I wouldn't go that far. We are also building good habits and attitudes
>>for the future.
>
>
> Right. And a good attitude is to not get bogged down in minutia like
> calculating outbound leg times for NDB holds when there's more important
> stuff to be thinking about.
>
> What's the weather doing? What's my fuel situation, i.e. how long can I
> let ATC park me here before I need to head to my alternate? What is my
> best alternate given the current situation? Can I review the approach
> plate one more time to make sure I really understand the procedure.

And, what are the odds of having to hold at an NDB in the 21st Century?

[Roy Smith]

In article >, Sam Spade >
wrote:

> And, what are the odds of having to hold at an NDB in the 21st Century?

Essentially zero. But, if your instructor (or flight school) is dumb
enough to send you for an instrument checkride in an airplane equipped with
an ADF, you may be called upon to demonstrate one. Which means they need
to train you to be able to perform one. Which, of course, is a huge waste
of your time and money, since it's a skill you will never use again after
the checkride.

Which is why, earlier in this thread, I said:

> But, the real way to do NBD holds is to tear that piece of crap ADF out of
> the panel and train in a GPS-equipped airplane. If your school doesn't
> have GPS in their trainers, find another school.

[Ron Rosenfeld]

On Sat, 28 Oct 2006 12:12:01 -0700, Sam Spade > wrote:

>And, what are the odds of having to hold at an NDB in the 21st Centur

On a few occasions, I've held at an NDB, but only one of those occasions
was in the 21st century, and not in the past few years since I've had a
GPS.

I held at the EPM NDB for 1/2 hour or so waiting for weather to improve,
before we had a GPS approach.
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

[Andrew Sarangan[_1_]]

Roy Smith wrote:
> In article >, Sam Spade >
> wrote:
>
> > And, what are the odds of having to hold at an NDB in the 21st Century?
>
> Essentially zero. But, if your instructor (or flight school) is dumb
> enough to send you for an instrument checkride in an airplane equipped with
> an ADF, you may be called upon to demonstrate one. Which means they need
> to train you to be able to perform one. Which, of course, is a huge waste
> of your time and money, since it's a skill you will never use again after
> the checkride.
>

Although I have never been assigned an NDB hold in the U.S, I have been
assigned NDB routes and holds in Canada. Just a couple of months ago, I
was instructed to hold at the Muskoka NDB. A few months earlier, I was
given "expect NDB approach... into Buttonville airport". This airport
is one of the largest GA fields in Toronto and has a perfectly good LOC
approach, but folks up there don't seem to shy away from NDBs.

[Roy Smith]

"Andrew Sarangan" > wrote:
> Although I have never been assigned an NDB hold in the U.S, I have been
> assigned NDB routes and holds in Canada. Just a couple of months ago, I
> was instructed to hold at the Muskoka NDB. A few months earlier, I was
> given "expect NDB approach... into Buttonville airport". This airport
> is one of the largest GA fields in Toronto and has a perfectly good LOC
> approach, but folks up there don't seem to shy away from NDBs.

Well, then I would fall back (yet again) to what I said earlier in this
thread:

> But, the real way to do NBD holds is to tear that piece of crap ADF out of
> the panel and train in a GPS-equipped airplane. If your school doesn't
> have GPS in their trainers, find another school.

Any flight school (at least in the US) which is not doing instrument
training in GPS equipped airplanes today is just ripping off their students.

GPS is no longer the way of the future, it's the way of today. I don't
think you can buy a new IFR airplane today which doesn't come with GPS as
standard factory equipment. This is everyday, routine gear for the
majority of the GA fleet. Not training new instrument pilots to use GPS is
like not training new primary students to use a nosewheel.

The way to do an NDB hold today is to punch the NDB name into your GPS and
hold at it just like you would at any other fix. If I was going into
Buttonville, and there wasn't a GPS overlay for the NDB, I would tell the
controller, "unable NDB approach, request LOC".

[Blanche]

Roy:
Expecting (assuming) all IFR training in the US to be in aircraft
that have IFR-certified GPS is a bit unrealistic.

Would you like to pay for an IFR-certified GPS to be installed in
my cherokee? I'd be delighted, and would even buy you dinner.

[RK Henry]

On 29 Oct 2006 19:58:08 GMT, Blanche > wrote:

>Roy:
>Expecting (assuming) all IFR training in the US to be in aircraft
>that have IFR-certified GPS is a bit unrealistic.
>
>Would you like to pay for an IFR-certified GPS to be installed in
>my cherokee? I'd be delighted, and would even buy you dinner.

Then what would a lifetime subscription for database updates be worth?

RK Henry

[Roy Smith]

Blanche > wrote:
> Expecting (assuming) all IFR training in the US to be in aircraft
> that have IFR-certified GPS is a bit unrealistic.

I guess that depends on your definition of "realistic".

I certainly think it is inappropriate, in the year 2006, to be giving
instrument training in an airplane that is not IFR GPS equipped. You
should be training people to operate in the kind of environment they are
going to be flying in after they pass their checkride. For the most part,
that means GPS. And that's going to be even more true every year that goes
by.

> Would you like to pay for an IFR-certified GPS to be installed in
> my cherokee? I'd be delighted, and would even buy you dinner.

I take it that you use your cherokee for instrument instruction? If that's
the case, then you should invest the capital to equip it with gear which
allows you to teach your students what they need to know. I'm afraid I
have no particular desire to fund the upgrade to your plane, however.

[Blanche]

Roy Smith > wrote:
>Blanche > wrote:
>> Expecting (assuming) all IFR training in the US to be in aircraft
>> that have IFR-certified GPS is a bit unrealistic.
>
>I guess that depends on your definition of "realistic".
>
>I certainly think it is inappropriate, in the year 2006, to be giving
>instrument training in an airplane that is not IFR GPS equipped. You
>should be training people to operate in the kind of environment they are
>going to be flying in after they pass their checkride. For the most part,
>that means GPS. And that's going to be even more true every year that goes
>by.
>
>> Would you like to pay for an IFR-certified GPS to be installed in
>> my cherokee? I'd be delighted, and would even buy you dinner.
>
>I take it that you use your cherokee for instrument instruction? If that's
>the case, then you should invest the capital to equip it with gear which
>allows you to teach your students what they need to know. I'm afraid I
>have no particular desire to fund the upgrade to your plane, however.

I'm not the teacher, I'm the student. My cherokee. And I don't have
an extra $4-8K to install an IFR-certified GPS. And the cherokee *IS*
the environment I expect to be flying after my checkride. Flying is
not my profession, nor will it be a career change.

Please, lay off the assumptions. Feel free to qualify your opinions
(and yes, they are valid but not in all situations) but make sure you
define your criteria.

[Roy Smith]

Blanche > wrote:
> I'm not the teacher, I'm the student. My cherokee.

OK, so my comment didn't apply to you. I was complaining about flight
schools who teach in non-GPS equipped airplanes. If you own your own
airplane, you can obviously equip it any way you like, and you're the only
one you have to answer to about your decisions.

> Please, lay off the assumptions. Feel free to qualify your opinions
> (and yes, they are valid but not in all situations) but make sure you
> define your criteria.

Well, I started out by saying:

> Any flight school (at least in the US) which is not doing instrument
> training in GPS equipped airplanes today is just ripping off their students.

Clearly, that doesn't apply to you. Thus, I don't understand why you took
exception to it.

[Sam Spade]

Blanche wrote:

> Roy:
> Expecting (assuming) all IFR training in the US to be in aircraft
> that have IFR-certified GPS is a bit unrealistic.
>
> Would you like to pay for an IFR-certified GPS to be installed in
> my cherokee? I'd be delighted, and would even buy you dinner.
>

That comparison is irrelvant.

Roy is speaking of trainers at a school that holds itself out to the
public to provide IFR flight training.

You are talking about your own personal airborne "rattletrap."

[Sam Spade]

Blanche wrote:
> Roy Smith > wrote:

> Please, lay off the assumptions. Feel free to qualify your opinions
> (and yes, they are valid but not in all situations) but make sure you
> define your criteria.
>
>

I'll give you something more concrete than an assumption: 10 years from
now, you might as well forget about conducting IFR operations in a light
aircraft if you don't have a TSO-C146 box.

So, it is really a limited form of training *today* to do all that work
for an instrument rating without becoming proficient in GPS operations
in the process.

[Newps]

Sam Spade wrote:

>>
>
> I'll give you something more concrete than an assumption: 10 years from
> now, you might as well forget about conducting IFR operations in a light
> aircraft if you don't have a TSO-C146 box.


Baloney. Operations won't be any different in ten years than they are now.

[Sam Spade]

Newps wrote:
>
>
> Sam Spade wrote:
>
>>>
>>
>> I'll give you something more concrete than an assumption: 10 years
>> from now, you might as well forget about conducting IFR operations in
>> a light aircraft if you don't have a TSO-C146 box.
>
>
>
> Baloney. Operations won't be any different in ten years than they are now.
>

Might be balony to you but it isn't to the folks that run the FAA.

[Roger (K8RI)]

On Sun, 29 Oct 2006 18:39:00 -0500, Roy Smith > wrote:

>Blanche > wrote:
>> Expecting (assuming) all IFR training in the US to be in aircraft
>> that have IFR-certified GPS is a bit unrealistic.
>
>I guess that depends on your definition of "realistic".
>
>I certainly think it is inappropriate, in the year 2006, to be giving
>instrument training in an airplane that is not IFR GPS equipped. You
>should be training people to operate in the kind of environment they are
>going to be flying in after they pass their checkride. For the most part,

Most trainers don't have instrumentation that old.
That means they have to put the ADF back in for my training.

>that means GPS. And that's going to be even more true every year that goes
>by.

I fly IFR in the system using VORs, RNAV, and NDBs. The only GPS I
have/own is a hand held.

>
>> Would you like to pay for an IFR-certified GPS to be installed in
>> my cherokee? I'd be delighted, and would even buy you dinner.
>
>I take it that you use your cherokee for instrument instruction? If that's
>the case, then you should invest the capital to equip it with gear which
>allows you to teach your students what they need to know. I'm afraid I
>have no particular desire to fund the upgrade to your plane, however.
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

[Kusi (us-ppl, sep, d.-ir)]

Alan Burke wrote:

> Hi,
>
> I'm studying for my IR and having some trouble in calculating the outbound
> times. Has anyone got any easy way of calculating the times.

Just finished mine over here in Germany. We were supposed to learn it,
however our flying clubs' Pipers have 2 GNS 430, with the excellent
"pictures"...

Anyway: Here is an easy method, if you have lets say 3+ miles to go in
a 100kts airplane:
Time: Subtract/Add the Wind-speed in seconds from/to your 1 min as
follows:
Wind angle <30° full speed. Wind angle 30..60° half speed. Wind angle
> 60° no correction.
Example: Wind 300/20, Course 290°. Wind angle=10°, that is "full
speed" so ADD 20seconds (20kts) to your 1 min.
By the way, that works with VORs as well.

Of course, in the real world, in a small plane...who gives a f* ?
You'll stay almost always in the protected area, no matter what heading
you fly.... ;-)

Cheers,

Kusi