OPNLguy

It mainly has to do with the advancements in jet engines that started in the late 1960s. Aircraft like the DC-8, 707, and 727 had to have fuel jettison systems because it was required by the FARs at the time. The reg in effect at the time was that if the aircraft max certified takeoff weight exceeded the aircraft's max certified landing weight by more than 107%, the aircraft had to have a dump system installed. The original 737-100 and DC-9-10 models didn't bust that 107% threshold, so they didn't require the systems.

As Boeing and McD grew their respective aircraft into various stretched versions (737-200, DC-9-30, DC-9-50, MD80) that were made possible by increasingly more powerful variants of the Pratt&Whitney JT8D, that 107% threshold was exceeded. Rather that have the manufacturers design and install a system to aircraft that were already in production, they took advantage of the increased power of the -9, -5, and -17 versions of the engine, eliminated the 107% requirement, and redefined the reg in terms of a minimum climb gradient percentage--which the aircraft with the newer engines could easily meet. Once the high-bypass engines like the CFM-56 started appearing in the mid-1980s on the 737-300 and onward, that trend continued, so still no need for a fuel dump system.

These days, about the only thing that has a fuel dump system are the original 707, DC-8, 727, as well as some 757s, and other twins that are capable of long-haul flying, where the spread between max takeoff weight and max landing weight is higher.

OPNLguy

The aircraft will get the damaged repaired, and a new engine, pylon, and cowling, and will eventually return to service, probably under a different registration number. While there was a fatality onboard the aircraft, that in and of itself doesn't warrant writing the aircraft off if it still some lifespan left. Decisions like this are based on numbers, not emotion. The LGA aircraft that was floated up to ALB for dismantling was due to the damage being beyond economical repair (busted keel beam, IIRC). The damage to the aircraft in PHL is far less severe...

smmrfld

Was hoping you would post here. Nice to have accurate information vs. the amateur guesses that are far too prevalent. Thanks as always for your insight.

Proudelitist

There is alot of talk about this guy thinking he was going to die. But was that realistic?

I get that in such a situation there is confusion and a lack of information..but I also know that de-compression in and of itself is not terminal to the flight envelope. Engine failure isn't either on multi-engine aircraft. A blown window is not structurally critical to the integrity of the airframe on a 737, particularly when only the glass is destroyed. I know that an emergency descent is standard procedure, and that the aircraft was still under control in that it's not rolling or yawing, or inverted. Had I been on the aircraft, I think I would have been confident in the survivability of the situation even without knowing the nature of the damage to the fuselage provided I sensed that that the aircraft was still under control. At least, as opposed to a situation like Alaska 261 where as a pax it would have been absolutely clear that this would be the end. But then again, who knows what this guy knew about flight and procedures.

skywardhunter

A decompression on its own is certainly not fatal to the aircraft's airworthiness, however it is a shocking event. Not only is there a sudden and rapid noise, chaos and change in air pressure, but what's often easy to forget watching videos is the impact it would have on the body in terms of the sinuses and inner ear. If you think your ears pop when the aircraft is climbing a bit quickly, try ascending from 6000ft to 32,000ft in 10 seconds, as that's what essentially happened. The cabin altitude would've been somwhere in the 4,000-6,000 range most likely, rapid decompression means suddenly your body feels like it's at 32k, so like you've suddenly gone up. It's easy to misinterpret as a descending sensation. Then, shortly after your ears pop like they've never popped before you're in a 4000fpm descent to 10,000ft, with yellow cups dangling in front of everyone's eyes, lot of wind noise and presumably screaming.

Practically speaking the most dangerous aspect of this incident was neither the decompression, nor the blown window, but the potential structural damage to the engine pylon and wing spar as well as the hydraulic systems. This could have easily also lead to structural or hydraulic damage to the left main landing gear if the debris had taken a different path.

nightkhan

While most of us on this forum are better informed and educated about aircraft safety, doesn't mean the general public and travelers would be. Who are you to judge how a person behaves and thinks when an aircraft window is actually blown open during flight and witnesses a fellow pax being partially sucked out of the blown window. For most people just turbulence is frightening enough, let alone an actual breach in the aircraft fuselage.

Was there certainty that the aircraft would stay intact, that no further damage would result, that everything needed to land safely would be functioning properly? To these passengers, absolutely not.

toomanybooks

I know the government sucks, and works at a snail's pace, and the safety and well-being of the public is LAST in the minds of these federal employees, but is there some reason these incredibly important things have to take YEARS to be implemented?

[politically loaded comment redacted by nsx to prevent reader reaction derailing this very active thread]

EmailKid

Just watched the GMA video interview with Facebook live person (via Yahoo), and while he sounds collected now, one would have to believe he thought his time "on this earth" was ending.

ursine1

Money. The reason is money.

MFLetou

That is so simplistic. There's a process to follow involving the manufacturer, the airline, the crew, the passengers, and a bunch of research. Some of these incidents are more obvious than others, but in other cases it simply takes time. They do a lot of simulations and recreations to try to determine and then confirm what actually happened. I've not heard that budgetary issues have held any of those things back, but maybe that's the case. It's also by the way incredibly insulting to say that the "safety and well-being of the public is LAST" in the minds of "these federal employees." Anybody who has any actual experience with the NTSB knows that almost nothing could be further from the truth.

OPNLguy

The question isn't necessarily distance, but time. One could theoretically be directly overhead of RDG at 32,000 feet (roughly 5 miles) and if the time it took to descend in a spiral was the same time it to descend directly into PHL, then PHL is just as "close" as RDG. The level of ARFF is higher at PHL, plus to have customer support.

enviroian

Can anyone speculate the COD of that poor woman? Lack of O2? Head trauma?

How horrible.

ursine1

After the last incident, the NTSB still hasn't finalized it's report. It's unclear if Southwest completed the inspections, which reportedly only take 2 hours each to complete.

https://www.reuters.com/article/us-p...-idUSKBN1HP0QK

From the article:

An early review of Tuesday’s failed Southwest engine found preliminary evidence of metal fatigue where a fan blade had broken off, Robert Sumwalt, chairman of the U.S. National Transportation Safety Board (NTSB), told reporters on Tuesday.

In August 2016, a Southwest flight made a safe emergency landing in Pensacola, Florida, after a fan blade separated from the same type of engine, and debris ripped a foot-long hole above the left wing. There too, investigators cited signs of metal fatigue.

“We are very concerned,” the NTSB’s Sumwalt said, referring to the general problem of detecting slow-developing metal fatigue.

“There needs to be proper inspection mechanisms in place to check for this before there’s a catastrophic event.”

Southwest said it was speeding up inspections of all related engines, which it expected to complete within 30 days.

Investigators said they would be examining maintenance records of the airline, which operates one of the world’s largest 737 fleets and has a strong safety record.

The 2016 incident prompted the U.S. Federal Aviation Administration (FAA) to propose ultrasonic inspections of similar fan blades and their replacement if needed.

Sumwalt said the NTSB would review whether the engines involved in Tuesday’s incident might have been subject to that directive, which is not yet finalised.

The U.S. FAA has estimated that checks, originally prompted by a safety bulletin from CFM itself, would require two hours per inspection.

Kevin AA

Why? It's just an arbitrary number. Given one fan blade flying away, the probability of fan blade 13 being the one to disappear is exactly the same as the probability of fan blade 7 (lucky 7!!!) disappearing or any other one of the 24 fan blades -- 1 in 24. It's less than a coincidence... it's superstition, which is an impediment to logic and reasoning.

ludocdoc

13 is lucky in Italy. It was just a number, in most cultures, till it just so happened that the Knights Templar were ambushed on Friday the 13th. Not good to be the main creditor of the French king...