Tuesday, December 19, 2006

The Supidest Thing I've Ever Done as a Pilot

So I'm over reading Mr. Completelys blog, and he relates a story of a guy making a dumb mistake and nearly ditching his CH-46 into the ocean.


Dumbest thing I ever did while flying an airplane (I've done dumber things while riding in them), was in a 172.

Now, as just about every pilot knows, a 172 has rather generous fore and aft CG limits, and a rather large gross weight margin. Those cessna boys were mighty conservative; and that fact alone has saved more pilots lives than I could ever count.

Now, I was never really one to bust limits, I'm pretty paranoid about safety; and I didn't intend to that day, but I did it without thinking about it, which is about as bad.

So anyway, there's four of us, two guys, two girls. I estimate the ladies are both about 120lbs, the other guy is 160, and I'm 260; and a 172 has a useful load of between 700 and 860lbs depending on the exact model, and equipment. This particular 172 was good for 760lbs.

Again, as every pilot knows, a 4 seat airplane really means two seats and a luggage rack; but if your pax are small folks, you can get away with four, so long as therie's no luggage and you don't need full fuel.

We're headed out to a grass strip on Marthas Vineyard; about a 45 minute flight; so we don't need much gas, about 7 gallons plus reserve, let's call it 14 gallons just for safety. I check the tanks and we've got about 18 gallons in there, so there's another 108lbs (100ll avgas is 6lbs per gallon).

That puts us right at gross; but it's a cool breezy day, I've got a long runway, and I'm not worried about it. It also puts us right at the rear CG limit, but again, I'm not worried.

So, we start up, and it feels a little heavy on takeoff, and we're about to go make a soft field landing; but hey, we're gonna burn off half that fuel anyway so I'm not worried.

The airplane seemed to need a lot of trim too, but I'm not used to flying full load and two pax in the back, so hey, I'm not worried.

So we get out over the water; and the weather is closing in a little behind us. The wind is picking up, and we've got one hell of a crosswind/headwind vector, at about 300 degrees to our direction of travel.

That's OK, we've got plenty of fuel... I'm not really worried.

At this point, we should have turned around. We're over water, with a strong headwind, and an airplane that isn't handling too great.

But I wasn't worried.

So, our 45 minute flight has just turned into an hour and 15 minute flight; and we've burned through about 2/3 of our fuel, because I've had to throttle up to compensate for the winds. Again, not too big a deal, we've still got enough to make it to several other airports, and back to land if necessary.

Then the winds get worse; and we've got a bit of a problem; now I'm starting to get a little worried.

The way the wind is blowing now, it's going to take us everything we've got 'cept a 15 minute reserve to either get to the Vineyard; or get back to a convenient mainland airport. We're actually a bit closer to the Vineyard than to land, so we decide to press on.

As the fuel burns off, it's increasingly clear we're aft of CG, because the plane is a bit mushy and because of the trim required.

At this point the wind is now near dead abeam, and I'm quartering into it by 20 degrees just to maintain our direction of travel.

So I call in and get the airport information, and we've got a BIG problem.

Cross winds, steady at 20kts, gusting up to 40kts.

The Cessna 172 has a maximum demonstrated crosswind component on landing of I believe 24kts (it's been a few years), and that number is not for a near gross weight aircraft, with an aft of limits CG, landing on a soft field. Flat out, it isn't safe to land this plane on a soft field with more than about 16-18kts of crosswind.

Unfortunately, at this point we don't have a lot of options. We can't fight back through the wind to get to the mainland. We could bingo to vineyard haven (the paved airport across the island), but if you try and fly a private light plane into vineyard haven without a flight plan filed for them, and a landing reservation, they get REALLY nasty; they'd probably make us declare an emergency before they'd let us land...

The good thing about this field though, is that it's wide and long. You can angle a lot into the wind and still have runout room. So, ok, I decide I'm going to make the approach, judge the crosswind on the field while I'm on final, and if I have to I'll go around and head for vineyard haven.

So I'm coming in on short final; I'm slipping it across the wind with a crab angle like you wouldnt believe; if I landed like that on a concrete strip I'd be off the runway in two seconds, presuming I didn't rip my gear off. You can believe my hand is ready to slam that throttle to the firewall for the go around in a heartbeat.

Just as I'm about to call it a missed approach, the wind dies to near nothing, and I drop it down as hard as I can without bouncing or digging in; then scrub the speed as hard as I can and hightail it for the tiedowns.

We got the airplane tied down; and ended up having a little microburst a few minutes later; though nothing of the sort was on the forecast or the radar when we left. It's New England, on the ocean; you can't predict the weather there any more than you can predict when a woman is going to change her mind.

So anyway the girls get out, and they both reach into the "luggage compartment" (kind of a joke on the 172, since it's just an empty space behind the seats, not some fancy compartment) and grab out these HUGE bags... or at least they look huge to a pilot who was edging gross weight anyway. I hadn't seen them load the bags in and hadn't accounted for them.

At this point I was a bit pissed; those bags had to weigh like 30 or 40 lbs each, what the hell. Not only that, but they're WAY behind the datum (the point from where the center of gravity is calculated)

Anyway, I borrow a scale, and I make everybody get on it. both of our little miss 120lbers are more like 140 each, Mr. 160 is actually 184, and I'm actually 272 that day. Plus the two 40lb bags; and that's 816lbs.

Plus the 108lbs of fuel... 924 lbs.

In an airplane with a 760lb useful load.

I recalculated what my weight and balance was on takeoff... turns out I was about 4" aft of limit; and I damn near shit my pants.

160lbs over gross with a C.G. 4" aft of the limit... I've known people who ended up smeared on the side of a hill for less than that.

Thank god for Witchita conservatism.