Actor Christian Oliver, 51, and His Daughters, 10 and 12, Killed in Plane Crash
It went straight in to the sea. Might be another elevator failure.
Naturally this is a Boeing 737 Max (actually a two month old 737-9 version).
WOW. How is Boeing going to explain this in such a new aircraft? Or even an old one for that matter.
Those poor bastards in Seattle can’t buy a break.
That is a plenty large enough hole to lose a couple of people out of quickly instantly had the 1 or 2 adjacent seats been occupied by unbelted passengers or lap kids.
The “good” news is it appears the door/hatch departed the aircraft cleanly. It’s big enough that had it not done so it might well have started a longitudinal tear extending aft some distance. There is circumferential structure every couple / few feet intended to prevent any tearing from propagating very far, but that’s only as effective as the engineers’ analysis was good and was based on an accurate model of the forces it needed to resist.
Also fortunate the door’s path of departure didn’t intersect the horizontal tail. That would have left damage that wouldn’t just buff out, and may even have left the airplane uncontrollable.
To my thinking, the clean departure suggests an assembly error where the door (or blind dummy in lieu of an actual door) wasn’t actually secured to the rest of the airplane properly. If the door is WAG ~2.5 x ~5.5 feet, that’s 2.5 * 5.5 * 144 = 1,980 square inches of surface area. At ~7.5 psi differential pressure vs. outside near top of climb or in cruise that suggests 1980 * 7.5 = 14,850 lbs force. So 7+ tons.
Unlike galley and entrance doors which are pivoting plug type that are held in place against solid fuselage structure by differential cabin pressure, this door, cargo doors, and overwing emergency exits are not plug-type. They are purely outward-opening and only their hinges and latches are resisting the outward pressure forces.
This sort of thing didn’t happen before they moved their headquarters to Chicago! 
That reminds me of the FQ (GQ, then) a few years ago about how much force is keeping the doors shut.
So at 16,000 feet what is the differential pressure?
I am very familiar with the door that fell out. It is only used as an emergency hatch on a couple carriers that have their -900’s carry more than 181 passengers. On other -900’s it is more of a plug than a door. It is still hinged on the bottom like the doors. The guy from Twitter above is incorrect, the sidewall panel at that location does not look nothing like the rest of the panels in the airplane. I would like to know how that plug could have come out, it is installed in Wichita during fuselage assembly. It is never opened in the factory in Renton.
Moving management away from where the engineering is done was a terrible idea. Replacing managers who came up through engineering with professiinal ‘managers’ was a terrible idea.
I’ve seen those mistakes many times in different businesses. Managerialism run amok. The idea that a manager of a soda company is interchangeable with the manager of an aviation company or a computer company, so long as they are properly trained in ‘management’. It’s never been true, but it allows white collar types with MBAs from Ivy league universities to leapfrog over those icky factory people.
Until planes start falling out of the sky.
@Sam_Stone nailed it.
Boeing had lost their way long before they moved HQ to Chicago. That was a symptom of how bad the managerial rot had already become, not a preceding cause of it.
It takes a long time to fully hollow out a good engineering and a good manufacturing culture. Like maybe about half a career’s worth of time. But it appears they may have finally succeeded.
tl;dr: I’d bet the differential pressure at 16K feet on an otherwise normal climb to an otherwise normal cruise altitude is about 5.5psi. So my calculation upthread overstated the force on the plug / door by ~1/3rd. But that calc would have been valid on most of the flights that plug / door had already endured since new.
Long version:
There’s not a simple direct relationship between current altitude and diff pressure. But we’re transitioning from ~0psi differential (psid) on the ground to ~7.5psid in cruise with the general goal of minimizing cabin rate of climb = rate of internal pressure decrease. The computer knows the cruise altitude we’re climbing to, knows the expected time to get there, and slowly climbs the cabin to use most of that time to get there.
Most of the outside pressure change occurs in the low altitudes. From ~15psi absolute (psia) outside at sea level, it’s down to ~10psia at 10K’, ~8psia at 16K’, 7.5psia at ~18k’, and ~4psia in the low 30K’ range.
Meantime a cabin cruising at e.g. 8K’ cabin altitude has an internal pressure of ~11psia. So the absolute pressure decrease in the cabin between sea level & cruise is roughly 4psia.
IME by the time we’re passing 10K’ the psid is somewhere around 4, and gets up close to 6 by 18K. Those are two triggering altitudes where we / I actually look at that gauge to evaluate how things are going. Otherwise we’re relying on pressure sensations in our ears, hearing normal or abnormal HVAC sounds, or loud bangs and cabin altitude alarms to tell use whether things are going well or not.
“The FAA is requiring immediate inspections of certain Boeing 737 MAX 9 planes before they can return to flight,” FAA Administrator Mike Whitaker said… The Emergency Airworthiness Directive (EAD) that will be issued shortly will require operators to inspect aircraft before further flight that do not meet the inspection cycles specified in the EAD. The required inspections will take around four to eight hours per aircraft. The EAD will affect approximately 171 airplanes worldwide.
If it’s an access port during construction why wouldn’t you make it an inside door when securing it so it’s always sealed by pressure? Maybe that’s the design and the frame was too flimsy. It will be interesting to hear all the technical details as this moves forward.
SD-nitpick: parts of planes …
jokes aside: fully agree, interesting to see that even moving business units from one floor to the next up WILL have impacts …(pos or neg. depending on what you seek)
It wasn’t an access/maintenance service door. It appears to be a structural plug that replaces a door that is not used in the specific layout of this aircraft. It would likely have a window and from the inside look like any other section of wall and window, but is discontinuous structurally from the rest of the fuselage, exactly like a door is.
I’m really curious to know if it was certified as a door (if it relies on the standard door hinges, latches, and locks to hold in place, maybe can be swapped out during a refurbishment) or as a permanent installation. I’m also wondering whether it was wired up as a door to indicate whether it was secure, or had means to prevent pressurization of the aircraft if it wasn’t.
I’m going to be following this investigation with interest!
The tabs sticking out in the interior don’t look like they would hold a screen window in place so they must be to hold the interior panel in place. I haven’t seen any exterior views to suggest a door frame structure.
There appears to be no distortion of the mounting flanges that a door frame would be bolted to. If they were used, and there was a failure of one and then more of the bolts, then there should be bent flanges. So it must not have been an actual door. The frame and flanges seem fine. Must be another method to attach a dummy section. Or worst case scenario the bolts were not installed. Various additional mounting systems were keeping it in place for a while. Then failed.
The plug actually looks quite shoddy in quality of installation in this picture. Not smoothly aligned with the body.
It doesn’t look significantly different from the equivalent A321 plug.
Here is how it looked when installed (missing the interior covering of course):
Comparing the 2 pictures posted it looks like it’s seated from the outside in so that it’s not held in place by pressure. There’s a possible cleat in the bottom right and attaching points are set so the door points are on the inside and the frame attaching points are on the outside.
Door and frame attaching points seem to be of similar design that are riveted into place and are then bolted to each other.