"Steven P. McNicoll" wrote in message
ink.net...

"Gary Drescher" wrote in message
...

A clearance to taxi to the active runway is implicitly a clearance to
taxi
across any other runways that are in your path.

What's implicit about it? If you're cleared to taxi to runway XX and
runways YY and ZZ are between you and runway XX then are you not
explicitly cleared to cross runways YY and ZZ?

No, you're implicitly cleared to cross runways YY and ZZ.

How else could you comply with the clearance to taxi to runway XX?

No other way. That's why the clearance to cross YY and ZZ is implicit in the
clearance to taxi to XX. But in order to be explicit, crossing YY and ZZ
would have to be *mentioned* in the clearance too. That's the difference
between being implicit and being explicit.

As AOPA has pointed out,
it would be safer if you needed an explicit clearance to cross any
runway,
whether or not it's active. Otherwise, a pilot who's disoriented (but
doesn't know it) may cross the active runway thinking it's an inactive
one.

How is that safer? A clearance to "taxi to" the runway assigned to the
aircraft is a clearance to cross ALL other runways that intersect the taxi
route to that assigned takeoff runway, active or inactive.

Here's how requiring runway-crossing clearances to always be explicit would
be safer safer. Suppose a pilot is in a situation where it is *not*
necessary to cross any runway in order to taxi for takeoff. If the pilot is
lost (but doesn't know it), he may mistakenly *think* he needs to cross a
runway and may then do so unexpectedly, possibly conflicting with other
traffic. (I've actually witnessed that happening.)

If runway crossings always required an explicit clearance, the pilot who
hadn't received such a clearance would thereby know he shouldn't be crossing
any runways, regardless of where he thinks he is or thinks he's going.

--Gary