30 minute reserve

"Darrell S" wrote in message
news:07Zre.462$wV5.435@fed1read06...
It wouldn't be practical to require an aircraft to be able to fly a given
distance with the fuel reserve. Too many variables and they'd have to
publish distance requirements for each type aircraft. Wind, aircraft
speed, etc. A ridiculous (I know) extreme example would be to require an
SR-71 to have reserve fuel to fly a 30 minute distance at mach 3. That
would be about 900 miles.

I'm not sure what you're trying to say. The current regulation essentially
requires just that. It requires enough fuel to fly for 30 minutes at cruise
speed, which for any given aircraft translates into a specific calm air
distance. Each aircraft is basically given its own regulatory distance
requirement.

Under the existing regulations, the SR-71 *does* require a 900 mile fuel
reserve, if flown under Part 91 of the FARs (since it's always being
operated by the government, those rules don't actually apply...but if Part
91 was being applied, it would be applied in just the way you say is
ridiculous).

Are you trying to say that the current regulation is ridiculous? If so,
you'd appear to be in agreement with the original poster. If not, why are
you saying that the current regulation is ridiculous?

I believe that the original poster is not suggesting that each aircraft get
its own distance requirement (as is basically the case now). I believe he's
suggesting that each aircraft should share the exact same distance
requirement with every other aircraft, regardless of cruise speed.

As far as that question goes: it's my opinion that the time-based
requirement more appropriately compensates for the relevant variables. It
certainly doesn't do it perfectly, but it takes into account likely reasons
for needing the reserve, such as being off-course (thus the greater
requirement for night than for day) as well as the fact that slower aircraft
can generally use a wider range of airports, and thus won't have to fly as
great a distance to get to a suitable one.

Sure, there are clear extremes that seem to indicate some flaw in the
concept. But those are just that: extremes. The regulations couldn't
possibly address each and every situation individually and perfectly. They
simply set some guidelines -- and quite liberal in this case -- for
operation of the aircraft, and it's up to the pilot to take appropriate
steps to follow those guidelines to the letter, as well as to the spirit.

Pete