Airlines in a Crisis

 Another retired armed forces top brass have been added to Boeing mgmt. This time a retired admiral. Yes I'm sure his nuclear bacground have made him very pedantic but do Boeing really need nuclear pedantry for its civilian airdraft production. Sounds expensive, not very productive and not something that would have a lasting effect. And not is there any actual nuclear apect to their civilian aircraft production program either. Another thing is that to reach the grade of admiral he has had to always toe the "company" line. That is not something you as a user of its products want in Boeings executive suite at this point in time. You would want somebody to shake things up a bit. Somebody with some diverging opinions and not just another yes man. Sounds like a press release friendly apointee thought out by finance people and lawyers and not what a engineering based top management would have been looking for. What Boeing need is somebody with a multilevel experience. and not o...

When its a set screw A set screw is fully threaded while a bolt is only partially threaded. (And yes a set screw has a head. If no head its called a grub screw.) This means a bolt fits better and thighter in its holes than a set screw does. A set screw only have the sideways or bending strength of a bolt 1 size down.  A bolt can only be thigthened to a certain point because it runs out of threads. Who knows if Spirit used set screws securing the plugs on a couple of planes because they ran out of the correctly sized bolts and expected Boeing to redo them anyway. Impossible to see/inspect unless you draw/remove the item in question. Or the head is stamped with a part number and you can see the head. Should Boeing have overengineered it so that a bolt also was covered by a sleeve that double secured the bolt wasn't overtightened and drew the frames closer, weakening them in the progress. A sleeve would also protect the bolt from the roller pins it was supposed to keep in place consta...

 What on the overwing exits stop them physically from being opened by a passenger with poor survival instincts during flight and did Boeing design engineers remove this safety mechanism from instructions for when installing a plug instead of a door. What other safety features did they omit on the grounds of cost saving in the design for using a door plug instead of a real emergency exit.  Normal cabin doors can't be opened during flight by design since they swing forward into the wind. There are few comments around on how this door (when installed) pivots. Is it up like the overwing exits or is it down since with such a small door there are probably no self inflating slide like the normal cabin doors. Or is it left or right. On the 737-200 the emergency exit overwing door came out loose and into the cabin. On the 737-NG-800 they swing up and out of the way. I doubt it just is pushed out and fall down because that could damage it during testing / maintenance. Would the overwing...

Further investigation points to that Spirit the maker of the 737 airframes do ship it with this blank in place but only temporarily fastened. Boeing then take the blank out to load the interior and then reinstall it.  The blank is like a door with a larger window and no manual opening mechnism and is being held in place by a frame rail with lugs but instead of movable pins and a handle like a normal door it is held in place with bolts and castelated nuts that should have split pins in them. As long as they are in place the doorblank can not be moved upwards (some say downwards and some later pictures of a locking bolt seems to support this) to a position where it can be opened / taken out. Again, regular inspection of these bolts have been made inpossible by having a complete panel on the inside. Questions remains over if split pins where installed. Bolted on parts can have the nuts unwinding themselves due to vibration. And the exact torque required to prevent this can be difficul...

On Max 9 an extra emergency exit door is replaced with a blank if you don't want it instead of not cutting the hole for it in the first place. And it was mechanically fastened instead of welded in place. And since the inner panel is just a normal panel making it impossible to do frequent checks on the blank, of course it eventually fell out taking the inner panel with it. And in this case after only 147 flights. That is less than 1 year in use.  On the other hand larger (in the hundreds) and original Max orders like the one from Ryanair get its own no mentioning of Max version number (737-8200) and  just uses a easily inspected normal door as it was originally designed for. This hole covered by a blank must be a financial quick fix to avoid producing 2 different versions of the airframe (with or without a door hole) and not something engineers recommended. And with it came a number of uncertainties, lets call them risks, that for the economists was a case of numbercrunchi...