I never said there wouldn't be math!

As I mentioned last week, I've been living vicariously through Aaron's posting of his adventures experienced while earning his private pilot's license.  Some of his more recent postings have dealt with learning to handle crosswinds.

(Hey! I'm on vacation and posting this through the magic of time travel, or something.  You might have to scroll through a few posts over there to find this one.  Aaron done writ good things, even if they're not always about flying...Read them!  Over.)

In ANY case, learning to fly a new aircraft in new and unusual circumstances like crosswinds can vex the best of pilots.

For example....

That airport is in Birmingham, England.  Remind me never, ever, never to book a flight there in the winter!

So, yeah, crosswind landings can be "sporty".  But did you know, our ancestors knew a way to make landing in one easier?

I suspect some folks might call it "magic", but the real answer is "math".

So, Sarge, yes, there will be math involved.  Specifically Geometry. Sines and Cosines to be precise.  (Sounds like a verse that could be sung to the Beverly Hillbillies, doesn't it?)

In any case, in almost all cases, wind is a good thing to a pilot.  Wind going over the wing is what gets them flying and then keeps them flying.  Once airborne, the direction of the wind isn't all that important, other than speeding up or slowing down your time enroute.  (If you want to see time stop, try flying in a northwesterly direction in the northern Pacific in the winter.)

Taking off in a crosswind can be a bit of fun, but if done properly, isn't usually too bad.  Previously viewed video notwithstanding.

Landing in a crosswind however.....Well the airplane will fly with it's nose pointed into the wind.  When landing, the pilot will align his flight path with the runway by pointing the nose into the wind according to a geometric formula which calculates the crosswind and headwind components of the actual wind direction and speed.

Which is all well an good while the airplane is in the air.  Once all the wheels hit the ground, the airplane is no longer flying and is now a ground vehicle.  Ground vehicles go the direction the wheels are pointed.  Unless the trucks (the landing gear assemblies) are steerable, that means the ground vehicle will go in the direction of the nose which is pointed towards the edge of the runway.

Great skill is involved in getting the nose pointed down the runway while keeping the upwind wing from beginning to fly again.  (As you move if forward to align the aircraft with the runway, it gains speed and may begin to fly again.)

Now, the Eagle was very aerodynamic which means if would fly without a lot of effort, so landing it in a crosswind was could involve all of your extremities.  Arms to control ailerons and throttles, legs to control rudder and brakes.  Sometimes swapping roles on an instant's notice.

When I first got to Kadena, many of the members of the squadron were involved in the aftermath of the KAL 007 episode.  My squadron had deployed to lovely Shemya AB in the Aleutians.  I was not in the squadron yet, so this story is at least second hand (and probably enhanced in the retelling by alcohol).

In any case, the squadron had deployed up there, being drug along by tankers, a flight of approximately 3000NM.  About 7 hours.  

Once in the vicinity, they got a weather report that put the weather very low, but within parameters although the wind was gusting outside crosswind limits.

Now, this was not normal times.  This was real.  The powers that be dictated that a squadron of Eagles deploy to Shemya and they would do so.  If the weather made landing impossible, the next stop was another 1500NM at Elemendorf.

The Squadron Commander decides to shoot the approach while the tankers and the rest of the squadron orbit at altitude.

He comes on down, enters the weather and is flying the ILS.  He's got the needles centered and as he breaks out of the clouds, he looks out the nose of the aircraft as he has several million times before.  

Nothing but water.  Out of the corner of his eye and outside the canopy bow (which is about 30^o off the nose), he catches a glimpse of land.  Glancing that way, he sees the runway.  Holding his heading, he sideslips it in to land.

After getting it on the ground and after a few minutes to get his blood pressure somewhat under control, he keys the mike, draws a deep breath and in a voice that is only slightly quaking now says, "Okay, it can be done.  Here's how....."

All 12 managed to make it down with no incidents.

So, juvat, what is the secret solution that our ancestral pilots knew and we have forgotten?

Well, we now build runways parallel to each other and if we build a cross runway, we build it at 90^o.

Our ancestors knew that the crosswind component is product of the sine of the angle between the wind direction and the runway direction times the wind velocity.  Which means that a 90^o crosswind of 30K will be 30K of crosswind.  

They would build the runways like they were built at Pyote AAFB Texas in WWII.

Pyote AAFB is west of Big Spring (Webb AFB) and near Monahans. it was abandoned in the early 60's.

An Equilateral triangle has 3 angles of 60 degrees.  Once you get more than 30 degrees off one runway heading, you are less than 30 degrees to another. The sine of 30 degrees is 1/2.  1/2 of 30K is 15.  Well within the crosswind landing limits.  In fact, you'd have to have winds of 60K in order to be at the landing limit for all runways.

Been to or at least by most of these, some are still operational although without all three runways, usually.
Source

There were a boatload of airfields in Texas in WWII, almost all from the map above that I could find on Google Earth were in some form of an equilateral.  The picture of  Shemya above shows they also had that option.

Laughlin also had, emphasis on the past tense, that style runway.

And, because Math is hard when you're actually flying the airplane, the rule of thumb I used was to take the wind velocity and multiply it by 1/6th for each 10 degrees off the runway heading.  That should get you within a knot or two.

An airplane in the air is an airplane.  Fly it.  An airplane on the ground is a big car (requiring a little correction into the wind to keep the wing down), drive it.  The couple of seconds it takes to transition from one to the other can be very exciting, enjoy!