The 4 horsemen of landing gear apocalypse!

Flying Safety, August, 2004 by Doug Wiser

For the future, we are developing a new high-strength stainless steel that will greatly diminish the three vulnerabilities of current alloys. This new alloy, Ferrium S53, is currently undergoing testing to develop material and design properties to include in a new specification. The next step will be to manufacture prototypes and qualify select landing gear components. The goal is a 500% improvement in SCC performance, greatly increased HE resistance, and much higher tempering temperature (for burn resistance). We have achieved these goals, and are working to optimize structural properties. In addition, we expect the new alloy will not require Cadmium or Chromium plating (passivate and Nitride instead). Hopefully, we can begin to use the new alloy for spare components in about 2007.

Cleaning activities can prevent corrosion if done properly, but is detrimental if it damages the coatings or washes grease out of joints. Generally, power-washing is always to be avoided. We like to say a dirty gear is a happy gear. Obsessively cleaning landing gear may help prevent some forms of corrosion, but it may cause more harm than good. It is for precisely this reason we have seriously contemplated changing the paint color of landing gear from white to gull-gray. Most commercial landing gear are painted gray to avoid highlighting every minor smudge that tempts unnecessary cleaning. Several years ago, we assisted AMC in the production of a video about landing gear cleaning and maintenance. You can find this excellent video at http://www.hill.af.mil/lg2/video/

The last two horsemen are Fatigue and Burns. Although fatigue problems can occasionally be initiated by field maintenance, it is primarily a design problem. Burns (both electroplating and grinding) are created during manufacturing and depot repair processes. In recent months our office has been handling a significant grinding burn crisis caused by one of our primary manufacturers. You may have been impacted by one of the resulting TCTOs to find and remove the suspect items. Although these two horsemen are of significant concern to us, they are not typically created by field maintenance and are addressed in a different forum.

Hopefully, this information will help you during landing gear maintenance tasks, and keep the Four Horsemen at bay!

By the last breath of the burner blow
better raise your gear,
The sound of doom knocks' hangar door
Lock up your crew chief and Airmen now
It's time to wield the chrome ...
For now you have got some company
The Horsemen are drawing nearer
On the stealthy steeds they ride
They have come to take your life
On, through the dead of flight
With the four Horsemen ride, or choose your fate and die
You have been dying since the day
You were forged
You know it has all been planned
The quartet of entropy rides
A cracking once, a cracking twice
No need for plating now!
Cause now you've got
the fight of your life
The Horsemen are drawing nearer
On the stealthy steeds they ride
On through the dead of flight
With the four Horsemen ride
or choose your fate and die ...