Winds on approach

Conventional wisdom (as I see it) is to execute a miss if you lose the
glideslope, go around, prepare and brief the localizer approach, then do
it.

That might be smart for some approaches, but if the only change between
an ILS and a localizer is the minima and the timing, being in the habit
of timing the ILS will save your bacon if you are low on fuel, racing a
storm, or otherwise in a tight spot when the GS goes TU.

IT also keeps you in the habit of timing other approaches, especially if
you don't fly many.

Jose
--
Get high on gasoline: fly an airplane.
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On the others though, if I kept power at the normal settings with the
headwind, I would've descended to the MDA further out... to me this
seems like an added risk... For timing these, if I didn't have an IFR
GPS or DME (they're new to me), how should I figure the ground speed
for timing?

As long as you are above the minima, and past any stepdown fixes, you're
ok. (This is one reason localizer minima are higher.) And being down
early gives you a better chance to break out to visual, and maybe fly
around the one cloud that would otherwise be in the way.

To figure ground speed, subtract the headwind from the airspeed. It
will be close enough.

Jose
--
Get high on gasoline: fly an airplane.
for Email, make the obvious change in the address.

Bob Gardner wrote

Conventional wisdom (as I see it) is to execute a miss if you lose the
glideslope, go around, prepare and brief the localizer approach, then
do it. Changing horses in midstream is not wise policy, especially in
the clouds and close to the ground. YMMV, but I'll never teach or
advocate the switch.

Nor do Part 121 Aircarriers permit their aircrews to change-over.

Bob Moore

One should always time the approach. In some senses it is easier. if
the GS goes bad, just go to the minimum altitude - one less needle to
keep track of.

Always time it. The wx could go worse or low on fuel - why abandon the
approach if you have it set up already?

What you advocate makes no sense to me. What is the rationale?

Bob Gardner wrote:
Conventional wisdom (as I see it) is to execute a miss if you lose the
glideslope, go around, prepare and brief the localizer approach, then do
it. Changing horses in midstream is not wise policy, especially in the
clouds and close to the ground. YMMV, but I'll never teach or advocate the
switch.

Bob Gardner


"Jose" wrote in message
...

You are timing your ILS approaches? Any reason for this? I can't find
anything in my 172P book that suggests 90 kts as an approach speed, even
in gusty winds. Seems fast to me.

IF one times their ILS, and loses the glideslope, one can often convert to
a localizer approach easily. And approach plates give canned timings for
various speeds, 90 knots is probably the best of the bunch for a 172. Of
course that's ground speed, not airspeed.

Jose
--
Get high on gasoline: fly an airplane.
for Email, make the obvious change in the address.

Is that FAA or air carrier rule?

That does not mean it is a bad thing.
It seems to me that abandoning an approach with the risk of fuel and
worse weather is worse.

Bob Moore wrote:
Bob Gardner wrote


Conventional wisdom (as I see it) is to execute a miss if you lose the
glideslope, go around, prepare and brief the localizer approach, then
do it. Changing horses in midstream is not wise policy, especially in
the clouds and close to the ground. YMMV, but I'll never teach or
advocate the switch.


Nor do Part 121 Aircarriers permit their aircrews to change-over.

Bob Moore

Bob Gardner wrote:
You are timing your ILS approaches? Any reason for this? I can't find
anything in my 172P book that suggests 90 kts as an approach speed, even in
gusty winds. Seems fast to me.


You're thinking in terms of landing; he's thinking of getting along with a
controller and then landing. When I was a student on my long solo cross
country, I dragged into RDU after a loooong final at 60 knots in VFR conditions.
For some reason, I seemed to have trouble getting permission to leave after I
got my logbook signed. Suddenly they had trouble hearing me.

Years later as a courier pilot, I regularly flew ILSs into that same airport at
120-140 knots... well above what the Lance called for, but it sure made for
happy controllers. With 2 miles of runway in front, I still managed to get the
beast slowed down in time after I broke out. Never had problems with the
controllers hearing me when I called either....



--
Mortimer Schnerd, RN
mschnerdatcarolina.rr.com

Consistency is valuable when you're still getting the hang of IFR
approaches. However, once past the initial phase, you need to
practice approaches at different speeds because eventually you will
need to move the airplane along with traffic behind you. Also, I find
that in windy conditions, a faster approach is easier to control so
often add an inch of MP to my customary power setting.

Tim wrote:


What you advocate makes no sense to me. What is the rationale?



Preventing accidents from shifting gears in a high stress, relatively
risky portion of the flight.

If you are flying an ILS, you should brief the ILS and fly what you
brief. Your choices should be one of two: Land or go missed. Trying to
make the most of a bad situation usually results in a worse situation.


If its a bad idea for a professional, 2 person ATP rated or eligible
crew, flying into places they are used to going on a daily basis, why is
it a good idea for a single pilot op?

As for bad weather getting worse, with diminishing fuel reserves.. does
anybody remember something about enough fuel to make your destination,
plus filed alternate, plus 45 more minutes. I dont think it was a
suggestion. And something about weather minimums at alternates?

If you are getting in this kind of a pinch, might want a refresher on
flight planning and rule requirements.

Dave

As for bad weather getting worse, with diminishing fuel reserves.. does anybody remember something about enough fuel to make your destination, plus filed alternate, plus 45 more minutes. I dont think it was a suggestion. And something about weather minimums at alternates?

If you are getting in this kind of a pinch, might want a refresher on flight planning and rule requirements.

and the ability to control the weather while in flight.

Jose
--
Get high on gasoline: fly an airplane.
for Email, make the obvious change in the address.

You should fly your normal approach *indicated airspeed*, not ground
speed.

This is particularly important if it's windy and bumpy. If you fly
that approach at cruise power to keep the groundspeed at 90 knots
you're likely above your Va, which can overstress the airframe.

On Mar 29, 12:59 pm, "kevmor" wrote:
I flew yesterday and did some practice approaches, and the winds were
about 20 knots gusting to 26-28. I've flown almost all approaches so
far in a different 172 that had a 180hp conversion. Because of the
winds, I kept almost full cruising power on the descents to try and
maintain my normal 90 kts ground speed for timing and roughly 500fpm
for the ILS.

This plane did have an IFR GPS indicating ground speed, but the one
I've been using for all other approaches didn't, neither DME. The CFI
informed me I should have used known power settings. What are your
thoughts? I'm not sure how I would've known the right power setting,
unless I used what I normally do, and accept the lower ground speed,
then adjust my descent for the ILS to a much lower fpm descent?