What is the reason for the Obstacle (Jepp) or Note (NACO) for Rwy 34 about
crossing the threshold at or above 10' AGL.

Is it for certain heavily loaded military a/c?

Under what sort of circumstances would it come into play?

Or is there something else I'm missing here?


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

On Thu, 15 Jul 2004 06:59:37 -0400, Ron Rosenfeld >
wrote:

>What is the reason for the Obstacle (Jepp) or Note (NACO) for Rwy 34 about
>crossing the threshold at or above 10' AGL.
>
>Is it for certain heavily loaded military a/c?
>
>Under what sort of circumstances would it come into play?
>
>Or is there something else I'm missing here?
>
>
>Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

Oops that should be "departure end"


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

On 15 Jul 2004 14:35:14 GMT, "KP" > wrote:

>
>Just as a guess because I've seen similar restrictions at other USAF bases
>and Pease used to be a USAF base, requiring aircraft to cross the departure
>end (not the threshold) at or above 10AGL/105MSL allows a Diverse Vector
>Area.
>
>That extra ten feet is probably all that's needed to ensure obstacle
>clearance for aircraft climbing at standard rate. It's a TERPS CYA.
>
>

You're right. That should read departure end.

But there are DVA's at other airports without the 10' note. I believe a
standard 35' AGL height is assumed.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

When the DP is created, the specialist has to initially assume aircraft
will cross DER at 0' and build the procedure with no crossing
restriction, even though 35' is standard for civil aircraft.
If they run into obstacles when building the procedure with a 0' DER
crossing elevation, they can place a crossing restriction at the DER of
as much as 35', thus alleviating the amount of penetration of the
obstacle clearance slope (OCS) as they can, which can sometimes result
in either no more penetration, or at least a lower climb gradient
needing to be published.
If they do this, then they need to put a comment on the DP file showing
how much of that 35' they used.
Although the crossing restriction used in building the procedure is
added to the FAA forms that support the procedure, they're not usually
published; but how to treat the restriction has been going back and
forth a few times, so it may have slipped through during a period of
time they were being published. On the other hand, it could be there
because the military asked for it to be there, since they don't
automatically apply a 35' DER restriction like civil pilots are supposed
to. In that case, they need to know that the crossing restriction is
there so they can limit their takeoff weight to meet the restriction.
It used to be scary watching the old "A" model C-135's taking off on a
refueling rendezvous, they used every bit of the runway to get airborne
sometimes.
Bridgeport, CT also has the DER restrictions published.

JPH


Ron Rosenfeld wrote:
> What is the reason for the Obstacle (Jepp) or Note (NACO) for Rwy 34 about
> crossing the threshold at or above 10' AGL.
>
> Is it for certain heavily loaded military a/c?
>
> Under what sort of circumstances would it come into play?
>
> Or is there something else I'm missing here?
>
>
> Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

On Thu, 15 Jul 2004 20:38:24 -0500, J Haggerty >
wrote:

>If they do this, then they need to put a comment on the DP file showing
>how much of that 35' they used.
>Although the crossing restriction used in building the procedure is
>added to the FAA forms that support the procedure, they're not usually
>published; but how to treat the restriction has been going back and
>forth a few times, so it may have slipped through during a period of
>time they were being published. On the other hand, it could be there
>because the military asked for it to be there, since they don't
>automatically apply a 35' DER restriction like civil pilots are supposed
>to. In that case, they need to know that the crossing restriction is
>there so they can limit their takeoff weight to meet the restriction.
>It used to be scary watching the old "A" model C-135's taking off on a
>refueling rendezvous, they used every bit of the runway to get airborne
>sometimes.
>Bridgeport, CT also has the DER restrictions published.

Thank you for that information. Verrry interesting.

I looked at BDR. That's where I learned instruments, back in the '70's.
If that DER was there then, it was not pointed out to me in my instrument
training.

I find it interesting that the published DER restriction is 35' for one of
the runways. That seems redundant since that's what we use, anyway.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)