Rolling door retainer

A method of providing a retainer for an aircraft hangar door to limit vertical displacement of the hanger door, comprising:

• a) providing an aircraft hanger having a lower supporting track positioned on one of a lower ground or a floor, an upper guide track and a hanger door, the upper guide track extending across a top and beyond opposite edges of an opening in the hanger, the hanger door having an upper channel member and a roller, the upper channel member having a web portion and a guide extending into the upper guide track and the roller including a grooved support roller that runs along the supporting track;
• b) positioning a reinforcement apparatus on each of a topside and an underside of the web portion of the channel member, each reinforcement apparatus defining an aperture that extends through the apparatus, and then forming a hole in said upper channel member in axial alignment with the apertures of the reinforcement apparatus,
• c) inserting a threaded bolt through said apertures and hole,
• d) securing said bolt to said upper channel member so that said bolt is movable axially toward and away from said upper guide track;
• and
• e) axially moving the bolt so that an end of the bolt is positioned a distanced from the upper guide track that is less than a depth of the groove of the roller to limit upper movement of said hanger door and prevent said hanger door from being removed from said lower supporting track.