Originally Posted by
spornrad
Spring-eject was probably avoided via glue by paint / stickiness of seals. These plugs are never opened. Maybe the springs not installed? Vibration in ground ops overcame the sticking after some cycles. At least the upper two bolts were clearly not installed or fell out, since the retainer eyes are completely undamaged on the pics.
Maybe
I speculate the springs are present even in the plug adaptation (to aid install and maintenance of the plug and frame.)
I cannot see a good photo of the upper attachment points in the doorframe through which bolts in the upper guide fittings would install horizontally towards the fore and aft. But I would agree it is likely the upper bolts were missing or stripped or (maybe) sheared.
If I were working on my boat or RV I would pull the plug in from the top or middle for leverage, step on both hinges to counteract the spring, shove at least 1 bolt in the top to hold it against the spring force, then go about installing all the bolts.
But I suppose the installation/maintenance SOP may be more prescriptive in where to grab/pull/push for proper positioning.
These kinds of adaptations need to consider human factors in install/maintenance. If it were a door, that door would have a proper handle and latch and a logical "closing" sequence that naturally counteracts the springs. The fact that this is a plug adapted to the airframe may cause the technician to improvise.