Formations Flying Standards

"Crossunders"

Cross-unders

A cross-under is the maneuver used to position wingmen from one side of the formation to the other side. Why would we want a wingman on, say, the left side vs. the right? Here are a few reasons I can think of:

You want to position the wingman on the upwind side for a formation landing.
You want to position the wingman/men for the break of an overhead approach.
To give a wingman a break from flying on the same side all the time!

The proper cross-under is done in several steps. The fundamental, by-the-numbers method is:

Ø      Flight lead gives the signal for a cross-under, visually or by radio call.

Ø      Wingman reduces power slightly to slide to the rear (nose/tail separation) and down to a position underneath lead (at least low enough to avoid propwash; 10 feet or so).

Ø      Wingman adds power to stabilize the rearward movement.

Ø      Wingman banks slightly to the side he wishes to move. Take the bank out after establishing 2-4° of heading differential.

Ø      Move across to the other side. Add power as you pass through lead’s 6-o’clock to keep from falling behind.

Ø      When reaching the desired position (mirror of the other side), take out the heading differential with a slight bank.

Ø      Add additional power to move up to the fingertip line and back into fingertip, now on the other side.

Here is a narrative of the pic sequence:

Initial position (fingertip) on the right side.
Stabilized after dropping straight back.
Halfway through the cross-under, at close to full power. Notice we are low enough that we can see the entire belly of lead.
Stabilized in the same position on the other side.
Back into fingertip (using lots of power)!

The biggest mistakes I see when new folks (and even veterans!) do cross-unders are:

Ø      Doing it too fast – trying to look like a Thunderbird or Blue Angel.

Ø      Not stopping the rearward movement fully, and going through the cross-under moving further behind the flight lead. This is the biggest mistake I see.

Ø      Not getting low enough (underneath lead) and getting buffeted by propwash.

Ø      Stopping the cross-under too soon, and being stuck too close in to lead.

For new folks, I even recommend moving out further during the cross-under to give you a little more wingtip spacing from lead. Then, when you move forward and reach the fingertip line, you can keep the power in and move in to fingertip.

What I keep in mind when doing a cross-under is what I would do if I was IFR/IMC. In other words, I like to do it in a controlled, smooth manner, staying close to lead at all times. Just relax and remember to use enough power to keep you from getting sucked behind lead.

When you do a cross-under from route position, you should already have plenty of nose-tail separation, so just move smoothly across to the other side.

For 4-ship procedures, please refer to the Cathouse Formation Standards.