NEWS | June 5, 2020

Aircraft General: Tie Down and Moor Aircraft per TMs

UH-60 Black Hawk crew members conduct routine maintenance on their aircraft
Photo by Charles Rosemond

When high winds kick up on the flight line, make sure you tie down and moor your aircraft like the -10 TM and TM 1-1500-250-23 (Aug 90) say. 

Your first step is to carefully read the aircraft’s -10 TM for typical blade tie-down and mooring instructions. When blades aren’t secured in high winds, wind gusts will blow rotor blades into the airframe, increasing the chances of aircraft damage.  

Your second step for tie-down and mooring information is TM 1-1500-250-23 (Aug 90), Aviation Unit and Aviation Intermediate Maintenance for General Tie-Down and Mooring, on all Army Aviation models including the AH-64, UH-60, UH-1, CH/MH-47, AH-1, and OH-58 helicopters.

Reading these manuals is important because something as small as slack in the ropes and chains is a sign that the process wasn’t done properly. If this happens regularly, it can be very costly for your unit.

TM 1-1500-250-23 (Aug 90) supplements, clarifies and standardizes the tie-down and mooring procedures in the aircraft’s -10 TM.  Whenever a conflict exists between the -10 and the -23 aircraft's TM, follow the latest version of TM 1-1500-250-23.
 
The Costly Effects of Improper Tie-down and Mooring of Aircraft
 
In the spring of 1989, Army aircraft at Ft Hood and Ft Polk experienced extensive and costly damage as a result of very high winds. In each instance, severe storm warnings had been issued and the prescribed procedures were then followed. But despite careful measures, aircraft suffered serious damage and combat readiness and resources took a hit.
 
No matter where aircraft sit on the airfield, if they aren’t flying, they must be tied down and moored like TM 1-1500-250-23 says. That way when heavy winds occur, you’ve already prepared ahead of time. And make sure you follow all tie-down and mooring TM procedures to the “T” so you don’t contribute to tie-down and mooring failure and the damage that can follow that.

Mooring on Non-paved Surfaces
       
Properly tying down and mooring your aircraft is important, no matter the surface type. Using the ground anchor kit, NSN 8340-00-951-6423, is recommended in all tactical environments for non-paved surfaces. The kit costs about $184.51. Be advised that these kits are a one-time use product. That means you can’t remove them from the ground unless they’re dug up.

Additional Info
 
H-60 and AH-64 crews make a note that the tie-down and mooring TM instructs you to set the horizontal stabilator in the neutral position or zero degrees.  Also, the CGU-1 B, 5,000-pound capacity nylon tie-down strap, NSN 1670-00-725-1437, is only authorized when hardstand mooring points aren’t available and the field mooring kit is used. For tie-down lines to main rotor blades, the line must be taut.  But be careful to ensure the blades aren't deflected below the static jacking droop position, as stated in your aircraft -23 TM.
 
Again, always protect aircraft from wind like lives depend on it because they do. And ensure you tie down and moor your aircraft like the -10 and -23 TMs instruct.

Note: Information in this article was published on Pages 23-24 in Issue 87 of Flight Fax (Mar 20).