Denton Texas sliding hangar doors fail – The windy day that can ruin your day!
Many of us have seen hangar door failures. Most notably Schwiess Doors has posted many photos of hydraulic doors that have failed, manufactured by Hydroswing® Hydraulic Doors. However, the case of hangar door failure at the Denton Enterprise Airport in Texas was from a wind event rather than mechanical failure. In this situation the wind was the predominant cause that allowed the door to be removed from its static position. Personally I have seen the aftermath of many hurricanes and there are common threads that lead to the demise and failure of the hangar doors. Consequently when the hangar is breached by the storm winds, the failure of a sliding hangar door increases.
No one plans for the failure during a storm. Most sliding hangar doors have wind pins or cane bolts for the panels, but are seldom used. These pins are typically dropped into place when the door is not in use. However in actuality that doesn't always happen, often the hole gets filled with dirt and debris so when the bolt is dropped it rest on the top. Line personnel should have the responsibility to check and verify they are clean and if they are inoperative have plant maintenance flush them out or vacuum them clean. I have also seen the cane bolts missing and used for caulks, so then there isn't even a cane bolt to secure the sliding hangar doors. Other times, the doors are not aligned and the bolt holes are completely missed when attempting to drop the wind pin or cane bolt into place. You can also retrofit the door system with cane bolts or tie down turnbuckles that will prevent the hangar door from being removed from the hangar door track.
Another issue that could occur is hardware may be loose and allow the door to slip off the upper guide beams, causing ultimate failure. I have also seen cast metal casters actually fracture at the flange. This is most common because there are a few pre-engineered metal building companies that use these inexpensive casters. They are not intended to be used with the condition, however sometimes the buyers fail to do the homework when specifying the sliding hangar door.
Lastly, remember not all sliding hangar doors are designed the same. Our firm designs the system as a whole, however I have seen one of our competitors engineer the piece, not the panel. So when the panel deflects during the pressures, which are positive and negative pressures, the panel may potentially dislodge and cause ultimate failure of the sliding hangar door. Remember the wind is much like a wave, the force comes in but it also must go out. So deal with reputable companies. Denton is not in a hurricane zone, but you don't need to be to have failure.
Do your maintenance annually on your aircraft, and that is a good time to plan your preventative maintenance on your sliding hangar door while your aircraft is at the A&P. Remember that all aircraft hangar doors need to be maintained regardless of the style or manufacture.