|
Here are some of my collected thoughts on flying.
I plan very much to be a safe pilot. I like to think I can learn
from other peoples mistakes.
I've run a lot of statistics and general aviation is roughly twice
as dangerous as driving per vehicle hours. It's about 3-4 times as
likely to kill someone though because of higher percentage of fatal
accidents. But due to the higher speeds it's about a wash with driving
when comparing fatalities per-passenger mile (planes travel faster plus
are much more likely to have multiple passengers). BTW - the airlines
claims of being "100X" safer than driving are based on
passenger miles which is inflated due to their high passenger counts.
Comparing vehicle hours (ie: %change you'll die sitting in a plane
versus a car for an hour) they're only about 5-10X safer than driving
(about 10-20X safer). This is even further skewed - Part 135 carriers
(big boys) and Part 121 carriers (commuter/regional) are often lumped
together - but Part 135 carriers are approximately 4-5X safer than Part
121 - Part 121 carriers are actually only 2-3X safer than GA (and thus
barely safer than driving).
There's a lot on what kills pilots - but the GA picture is muddier
because most accidents don't get the attention that the big crashes do
(GA averages just under 1 fatal crash per day in the country) and the
lack of flight data and cockpit voice recorders. But it's pretty simple
- most crashes are on landing but less than 1% of these are fatal
(slow, close to ground). Number 1 cause of fatal crashes is the rough
category of "manuvering flight" - stuff close to ground like
pattern work, approach, takeoff. Over 1/2 of these are stall/spin
situations (the low altitude makes an otherwise perfectly recoverable
stall/spin fatal). Number 1 cause of enroute crashes (most of which are
fatal due to speeds and altitude) is weather with night being second,
fuel third, and mechanical being a distant 4th.
Of the fatal crashes close to 1/2 can be attributed to weather -
even the low altitude ones. The pilot was manuvering at low altitude to
stay clear of clouds - "scud running".
However - most weather and night crashes officially get charged to
pilot error because the pilot shouldn't have been there (non-instrument
pilot in instrument conditions is automatic pilot error). Also - most
weather/night crashes are not CFIT (controlled flight into terrain),
they are either loss of control (vertigo, spatial disorientation, etc)
or structural failure (icing or thunderstorms). Almost all of these
crashes can be traced to some error in judgement. Some of these errors
(small fraction) are relatively innocuous errors that should be
"recoverable" (like passing an airport in deteriorating
weather and turning back just a few minutes later but getting unlucky).
Most are repeated failures in judgement that border on the unbeliveable
when you read about them after the fact - many coming from pilots that
had a sound repuation for good judgement.
More and more reading that I do points many of these "pilot
error" crashes either enroute or after an enroute leg to hypoxia.
The FAA requirements state that 12500 or less and you can fly forver
without 02. Over 12500 but less than 14500 for < 30 minutes, >30
minutes requires O2 for the pilot, >14500 requires 02 for everyone.
NASA Ames Research Center and military regulations disagree. NASA has
done most of the research for the military and has very different
views. The military generally requires O2 for sustained flight over
9500 by day and 7500 at night. It's a documented scientific fact that
O2 levels drop by about 5000 feet at night due to cooling air and the
different thermal charecteristics of O2 and N2 (gaseous Nitrogen) yet
the FAA rules don't reflect this - there is no night/day distinction in
the FAA regulations. There have been crashes with evidence of hypoxia
as low as 7500 by day and 5500 by night.
One thing I'm working on is my "personal minimums" - the
set of rules that I use to make my go/no-go calls. Ahart (my FBO) has a
pretty conservative set of minimums that are a good starting point. I'm
also thinking about adding O2 into my minimums in regards to altitude.
You can get a decent portable 02 rig for flight for < $1000 so that
may actually go on my wish list ahead of a nice GPS. I'm thinking of
maybe 6500 by night and 10500 by day for sustained flights.
It's not much of an issue for most flights I'll do - but it does
affect flying to Tahoe or over Yosemite. 6500 is picked partially
because it's the lowest westbound VFR altitude (see http://www.californiaair.net/flightopps/FlightLevels.html)
that safely clears the tallest terrain for 100 miles North/South in the
Coastal Ranges - basically the area I'll fly most. There's a lot of
terrain in the area up to about 4400 feet so 4500 is no good - farther
north there's some 7500 stuff but that's the only stuff over 4800 West
of the Central Valley. North or South of the ends of the Valley the
taller stuff comes west to the Coast - but that's 200 miles either way
from here.
Even the Sierra foothills stay under 5000 until about 100 miles east
of here - then it's up up up. There's only about 3 places for about 350
miles you can fly across the Central/Southern Sierras safely under
12000 feet - Donner Pass (I-80), Kirker/Luther/Echo and Tioga pass. Of
those only Donner pass is usually small plane friendly wind wise.
Otherwise it takes about 13000. None of these passes is flyable most of
the winter due to mountain obscuration and icing.
See my page on Building versus
Owning for my thoughts on plane ownership.
|
