Port Aft Bulkhead Latch Go/No-Go Criteria

The Port Aft Bulkhead Latch Go/No-Go Diagram is used for the door closing case in which the Port door is stuck in the Ready-to-Latch position (RDY) for > 6 seconds and does not go to CL on the display. The RDY position means that the door is within 4° of being fully closed, and at that position the bulkhead latches can grab the door and "zipper" it closed from the bottom up, assuming the door has not been thermally warped. If the scallop (the rounded part that hangs down from the corner of the door at the bulkhead) is on or below the top of the target line (the black stripe located on the aft bulkhead below the vertical stabilizer), then the crew is Go to continue. If the scallop is above the top of the target line, then the crew is No-Go to continue. Even though the top of the target line represents the door being 1.73° open -- within the 4° envelope -- MCC would want to look at things before giving the final Go to proceed.

Except as noted, all photos are single frames from a digital video of the doors opening in the OPF, cropped and brightened. Orbiter is OV-105, in OPF-1 on 3/13/00, taken from the Flight Deck via Window W9.

Door opening, from fully closed until scallop is above the target line	Door opening, from scallop above the target line to full open
With the doors opening (silhouetted against a white backdrop in the OPF), the scallop for the Port door is clearly visible.
This sequence of photos from STS-113 (OV-105, 11/02, window W10) shows the port door closing. The scallop is clearly visible in these pictures as well. Click on each photo for a larger version. (Photos sts113-338-007 through -010).
	The scallop is visible above and to the right of the right edge of the target line, at the upper edge seal bracket. The scallop should not be confused with the shear roller, the larger structure to the left of the scallop above the target line and which partially obscures the bottom of the vertical stabilizer. The crew would be NO-GO to continue with door closing procedures if the CL indication was not present and if the door was stuck on RDY. This is approximately the 4° open point, at which the RDY indications would first be recieved. Photo sts103-354-037 from STS-103 (OV-103, 12/27/99) via window W10, at about the same location. Select picture to enlarge target line area.
	The Port door scallop is just at the top of the target line. At this point, the crew would be GO to continue closing the doors. The shear roller is above the top of the target line, at the centerline of the vertical stabilizer. As another possible visual cue, the Port radiator obscures the top half of the bulkhead roller from just above the center pin.
	The Port door scallop is now below the top of the target line, but above the bottom. The shear roller is now at the top of the target line, making this a possibly misleading visual cue. The crew would be GO to continue closing the doors per the diagram. This shows approximately the same location, from STS-113 (also OV-105, this from window W10). Photo sts113-338-011. Click to enlarge.
	The Port door is almost completely closed. The scallop is below the bottom of the target line, though not completely closed, and a small part of the bulkhead latch roller is still visible.
	The door in the fully closed and latched position. The scallop is visible below and to the right of the target line. Again from STS-113, W10, photo sts113-338-013. Click to enlarge.

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Previous step in door closing: Bulkhead Latch Motion
Next step in door closing: Stopping the Starboard Door While Closing
Compare to Starboard Bulkhead Latch Go/No-Go Criteria

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created March - May 2000 / last updated April 2002