Bush to consider shutting down GPS in extreme emergency

But they are also in "very high orbits" by any reasonable definition.
They are in a 12 hour orbit - one might call that "geosynchonous/2" at
around 12,000 miles. That's at least three earth radii above the
surface. A compass, ruler, pencil and a little drawing should be
enough convince you that this is high enough to cover most of a
hemisphere.

Ed

 

They still more than an Earth diameter out there.

 

In the US, you're required to do that if you fly it IFR. The requirement
is to be able to climb at 50 ft/min to 5,000ft or the MEA, whichever is
greater, with the critical engine inoperative. That can be a problem for
many light twins, and the payload has to be cut back considerably,
depending on the temperature, of course.

Note, this isn't a certification requirement, it's an operational
requirement, and only IFR.

 

I wouldn't.
If an engine quits right at takeoff in a light twin, shut down
the other one.
But if it quits anywhere else, it gives you a lot more time to
select a place to land, even if you cannot maintain altitude.

The only problem with this "precise information" is that it's
simply WRONG.

"Starting with the obvious, large aircraft certified under FAR
Part 25 have certain redundancies and required performance
capabilities that are not required for light aircraft certified
under Part 23 or the old CAR 3, as most of the fleet is. For
example, an engine failure on takeoff in a light piston twin
does not guarantee the pilot any climb performance--none. All it
offers is the opportunity to make a decision. In Part 25
aircraft, which includes some business jets, there is a required
level of performance that gives the pilot something to work
with."

Read it again: "[A]n engine failure on takeoff in a light piston
twin does not guarantee the pilot any climb performance--none."

http://www.aopa.org/asf/asfarticles/sp9710.html

Be careful of the information you get on usenet.

 

"truth" in navigation means a point. There is almost no way that the average
position from GPS over a very, very long period will converge on that point.
The average will wander around near it.

"practical purposes" would put that average position within a quarter meter,
maybe less. But that is not a 'truth' position.

 

Of course. It uses GPS. So it could hardly be available before GPS now, could it?

Through communications and accurate clocks at each end of the communications
pipe, a converged time solution within microseconds (if not better) is quite
feasible. I belive SONET among other high speed nets relied on this to
microsecond level, and other networks to higher levels.

But all this is of course to avoid higher cost clocks at each end. With higher
accuracy atomic clocks, syncronized from a travelling master, accuracy and
syncronization could be attained at ever increasing accuracy. At a cost.

 

(Iolaos) wrote in

Which is what I said. Part 23 requires that the aircraft demonstrate a
climb with the critical engine inoperative and the gear and flaps
retracted. It does not specify that it has to do that under all
conditions, nor with the gear down. The manufacturer can demonstrate it
with only a pilot aboard and a few minutes' fuel. It just has to have a
chart with the conditions under which it can and can't climb available.
Read my post a little closer.

 

Microseconds aren't good enough today.

That would not be cost-effective.

 

That depends on a number of things. In any case, it could come very
close indeed, as close as any other form of surveying might place it.

I'd expect a few centimetres over time, depending on various things.

 

Stan,

yes, that makes a lot of sense to me. I can only say that I
wouldn't like to fly VFR either, if I knew that I couldn't climb
on one engine.

This is very theoretical for me, as I have neither an IFR rating
nor a multi-engine rating.

Hans-Georg

 

On 20 Dec 2004 23:36:08 -0000,

Yes, I'm aware of that. But what I'm saying is that a twin that
cannot climb on one engine is much more risky than one that can.

But this depends only on its loading. You can load a light
piston twin such that it does climb on one engine. And that's
what I would do if I were in that situation.

Hans-Georg

 

Logically, of course, the average position can never be a single point.
If all readings showed the same point you wouldn't need to calculate
the average

Juergen Nieveler

 

No, it does not.

In fact, the airplane can be certified under Part 23 even if it
cannot climb SE under ANY conditions.

, nor with the gear down. The manufacturer can demonstrate it

It doesn't have to demonstrate a climb under those condition,
either.

 

can.

True.
If that's your consideration, fly a Part 25 certified twin.
But be prepared to pay for it.

No, you cannot.
There is no requirement in part 23 that requires an aircraft
certified under that part to climb AT ALL on a single engine,
even if the airplane is completely empty.

 

On 22 Dec 2004 03:41:23 -0000,

Problem with such a plane might be that nobody would buy it.

Do any twins exist that cannot climb on one engine at all? I'd
be surprised, except perhaps for some unusual special-purpose
planes.

My thought is that, when the designer of the aircraft reduces
its performance until it can no longer climb on one engine, the
utility value of the plane suddenly drops sharply at that point.
So, if I were designing such planes, I'd hate to do that.

Hans-Georg

 

(Iolaos) wrote in

So what do you make of this?
§ 23.67 Climb: One engine inoperative.

(a) For normal, utility, and acrobatic category reciprocating engine-
powered airplanes of 6,000 pounds or less maximum weight, the following
apply:

(1) Except for those airplanes that meet the requirements prescribed in §
23.562(d), each airplane with a VSO of more than 61 knots must be able to
maintain a steady climb gradient of at least 1.5 percent at a pressure
altitude of 5,000 feet with the—

(i) Critical engine inoperative and its propeller in the minimum drag
position;

(ii) Remaining engine(s) at not more than maximum continuous power;

(iii) Landing gear retracted;

(iv) Wing flaps retracted; and

(v) Climb speed not less than 1.2 VS1.

And it goes on with requirements for heavier aircraft......

http://tinyurl.com/4qygz, the cited paragraph at ecfr.gpoaccess.gov, the
Electronic Code of Federal Regulations.

 

(Iolaos) wrote in

Have you actually read Part 23?

 

I should have repeated, as the AOPA article I quoted said, that
"For example, an engine failure on takeoff in a light piston
twin does not guarantee the pilot any climb performance--none."

What I meant is that you cannot reduce the load of many, if not
most, part 23 aircraft enough to guarantee ANY climb performance
*at takeoff*.

Sorry if I was unclear.

Part 25 aircraft are required to be able to make a successful
takeoff at gross takeoff weight if the engine fails at takeoff
safety speed (V1) while still on the ground and maintain a
certain climb gradient.

Part 23 aircraft are not.

 

This is not too relevant in this discussion and apparently the decision
was already made. Galileo will come and stay.

Ejo

 

What did Americans fight a civil war for?

Jan