Seneca down at Avalon

"Maule Driver" wrote in message
r.com...

"Larry Dighera"
That is a tricky approach. VOR behind and above the airport.

What is it about those circumstances that causes you to characterize
the Avalon VOR/DME-B approach as tricky?

Thanks for taking the bait. On one hand, nothing is tricky about it if
flown as published (obvious and self-evident). But a bunch of folks died
here by not doing so. So what's tricky?

One way of describing what's tricky is that you can fly the approach as
published laterally, never descend below MDA, and crash.

I would not describe it that way - rather, more acurately, you fly the
approach and fail to execute the missed as published. That will get you
dead in many places and this is aout as "trickless" as they come. The
approach is named VOR/DME - so what is the trickiness?

All the information is on the approach chart. There is not much to do on
the final segment - just remain at 2100, keep a heading and then make sure
you know when to go missed. There is no timing on the approach chart and it
seems fairly clear that the approach uses DME fixes.




The fact that the MAP is a DME reading is perhaps trickier than having a
flag flip, needle spin,beacon sound, timer zero-out, or an intersection
passed. GPS helps. But such is the nature of many VOR/DME approaches.
I've *never* flown a VOR/DME approach using a DME so this is a bit of
conjecture on my part.

For those of you familiar with it, would I be right in guessing that
familiarity with VFR flight there might not make the need to climb as
obvious as it is when IMC?

I would guess the opposite. The mountain is clearly visible in VMC,
and apparently was not immediately visible when this accident
occurred.

Have you flown there? I was thinking of a place like Roanoke where it is
obvious after flying there VFR that there is a MOUNTAIN behind one of the
runways. The mountain remains in this pilot's mindseye even when in IMC.
Looking at the approach plate for AVX, it seems like the airport and the
location of the VOR are about 500' different. I'm guessing that the VOR
may
be on a highpoint. Flying there VFR I was trying to imagine whether one
would tend not to be aware that there is a critical rise in terrain in
some
directions. Especially sinced the rise is not obviously aligned with a
runway. But I've never flown there nor do I have a sectional.

So here's the trick. We're on an instructional flight, the student has
done
everything right but and is flying at MDA. We're looking for the airport
but the student has missed the DME indication for the MAP. The instructor
sees the error or not, but may decide to wait to see the student catch it
(very wrong in IMC). They proceed at MDA into the only navigational aid
on
the entire approach. The (possible) fact that in the pilots' minds eye,
they are flying to a hilltop airport surrounded by water may suggest that
flying 2100 feet above the water and 500 feet above the airport is not
going
to result in hitting terrain.

Flying it as published without error of variation would of course
eliminate
this speculation.

"Richard Hertz"
Thanks for taking the bait. On one hand, nothing is tricky about it if
flown as published (obvious and self-evident). But a bunch of folks
died
here by not doing so. So what's tricky?

One way of describing what's tricky is that you can fly the approach as
published laterally, never descend below MDA, and crash.

I would not describe it that way - rather, more acurately, you fly the
approach and fail to execute the missed as published. That will get you
dead in many places and this is aout as "trickless" as they come. The
approach is named VOR/DME - so what is the trickiness?

All the information is on the approach chart. There is not much to do on
the final segment - just remain at 2100, keep a heading and then make sure
you know when to go missed. There is no timing on the approach chart and
it
seems fairly clear that the approach uses DME fixes.

Well, I have to agree that it's all there and if you fly it as published, no
problem. But this approach seems a little different than the 'typical'
non-precision approach.

I took a quick look at the first 111 approaches inf SE 2 of 4 NC & SC. I
looked at at all non-precision, non-GPS-only approaches. There were 38 such
approaches.32 of them had a missed approach point that was over the runway.
Of the six that had MAPs short of the runway threshold, 4 of those were
TACAN (military?) only approaches. Only 2 were similiar in this way to AVX.

Nothing wrong with different. Not necessarily tricky but I can see how a
careless pilot might continue on at MDA past a MAP short of the runway while
'searching' for a view of the runway. Thinking perhaps that I can see
straight down at the MAP so I'll just proceed along another mile (45 secs)
until I see the runway below then I'll rack it around and circle to land.

I'm not saying these folks were careless, just trying to learn something
from the accident.

On second thought, I'll stick with tricky.

"Maule Driver" wrote in message
r.com...
"Richard Hertz"
Thanks for taking the bait. On one hand, nothing is tricky about it
if
flown as published (obvious and self-evident). But a bunch of folks
died
here by not doing so. So what's tricky?

One way of describing what's tricky is that you can fly the approach
as
published laterally, never descend below MDA, and crash.

I would not describe it that way - rather, more acurately, you fly the
approach and fail to execute the missed as published. That will get you
dead in many places and this is aout as "trickless" as they come. The
approach is named VOR/DME - so what is the trickiness?

All the information is on the approach chart. There is not much to do
on
the final segment - just remain at 2100, keep a heading and then make
sure
you know when to go missed. There is no timing on the approach chart
and
it
seems fairly clear that the approach uses DME fixes.

Well, I have to agree that it's all there and if you fly it as published,
no
problem. But this approach seems a little different than the 'typical'
non-precision approach.

I took a quick look at the first 111 approaches inf SE 2 of 4 NC & SC. I
looked at at all non-precision, non-GPS-only approaches. There were 38
such
approaches.32 of them had a missed approach point that was over the
runway.
Of the six that had MAPs short of the runway threshold, 4 of those were
TACAN (military?) only approaches. Only 2 were similiar in this way to
AVX.

Why does it matter where the MAP is? The MAP is the MAP - if you don't have
the required visual element(s), go missed. What is so tricky?
What is different on this approach. It can't get any easier.



Nothing wrong with different. Not necessarily tricky but I can see how a
careless pilot might continue on at MDA past a MAP short of the runway
while
'searching' for a view of the runway. Thinking perhaps that I can see
straight down at the MAP so I'll just proceed along another mile (45
secs)
until I see the runway below then I'll rack it around and circle to land.

I'm not saying these folks were careless, just trying to learn something
from the accident.

I would say they were careless. Especially the CFII.


On second thought, I'll stick with tricky.

"Richard Hertz"
Why does it matter where the MAP is? The MAP is the MAP - if you don't
have
the required visual element(s), go missed. What is so tricky?
What is different on this approach. It can't get any easier.

You are right, it can't be any easier. Maybe more forgiving but that's not
a requirement

Nothing wrong with different. Not necessarily tricky but I can see how
a
careless pilot might continue on at MDA past a MAP short of the runway
while
'searching' for a view of the runway. Thinking perhaps that I can see
straight down at the MAP so I'll just proceed along another mile (45
secs)
until I see the runway below then I'll rack it around and circle to
land.

I'm not saying these folks were careless, just trying to learn something
from the accident.

I would say they were careless. Especially the CFII.

Yep.