Flyegypt have pranged 3 Boeing 737’s in the past week - action needs to be taken
Wizofoz wrote :"Always thought it odd you could set the park-brake of a 737 in flight- i mean; what could go wrong?"
As far as I can remember on the -200 B737 the park brake was just a latching mechanism and the anti-skid was designed to protect the likely hood of a pilot landing with feet on the brakes, via a spin up channel, the anti skid would not necessarily know if the brakes were foot operated or latched; I am sure this safeguard exists on the more modern versions of the B737 and most airliners.
Outside of a crash landing, I have never heard of two halves of a bolted wheel separating, all the bolts would need to shear and the axle nut go missing; flange failures yes (L1011 Flt 162) and especially in 1950-60's flanged magnesium wheels which were another story.
As far as I can remember on the -200 B737 the park brake was just a latching mechanism and the anti-skid was designed to protect the likely hood of a pilot landing with feet on the brakes, via a spin up channel, the anti skid would not necessarily know if the brakes were foot operated or latched; I am sure this safeguard exists on the more modern versions of the B737 and most airliners.
Outside of a crash landing, I have never heard of two halves of a bolted wheel separating, all the bolts would need to shear and the axle nut go missing; flange failures yes (L1011 Flt 162) and especially in 1950-60's flanged magnesium wheels which were another story.
Ahh, how typical - Anson & Co moderating the moderators. Talk about objectivity!
But, you know, I think I shall join the ranks of the multitudes of professional pilots who have departed this website to focus on the azure skies, without being troubled by the opinions of armchair experts. This thread neatly summarises why.
I was thinking: soft tyre - heavy landing - soft tyre cannot cushion shock - wheel hits ground hard - rim separates. But highly improbable, I grant you.
So what then would have caused a rim to break off.......badly corroded wheel? A cheap refurbished wheel reassembled incorrectly with the wrong bolts, or re-using the old bolts, or torqued incorrectly perhaps?
My suspicion is a maintenance issue in some form.
Locked door
Not exactly correct.
The first few were due to the wheel bearings packed with the wrong grease.
The last one, was due to the wheel being dipped in solvent to degrease it before assembly. The sintered heat shield within the wheel acted like a sponge and soaked it up. Usually after assembly, the wheel would go in to stores for a while and the solvent would evaporate. On this occasion the wheel came straight from the workshop and was fitted on the line before the aircraft operated to MAN.
Not exactly correct.
The first few were due to the wheel bearings packed with the wrong grease.
The last one, was due to the wheel being dipped in solvent to degrease it before assembly. The sintered heat shield within the wheel acted like a sponge and soaked it up. Usually after assembly, the wheel would go in to stores for a while and the solvent would evaporate. On this occasion the wheel came straight from the workshop and was fitted on the line before the aircraft operated to MAN.
Uplinker
"It is rare for two halves of a wheel to separate full stop! What on Earth could have caused that?
I was thinking: soft tyre - heavy landing - soft tyre cannot cushion shock - wheel hits ground hard - rim separates. But highly improbable, I grant you.
So what then would have caused a rim to break off.......badly corroded wheel? A cheap refurbished wheel reassembled incorrectly with the wrong bolts, or re-using the old bolts, or torqued incorrectly perhaps?
My suspicion is a maintenance issue in some form."
I would agree.
And if so - depending on whether or not FlyEgypt overhauls its own wheels - it may turn out to be grossly unfair to point the finger at the operator at all, in respect of the first incident.
"It is rare for two halves of a wheel to separate full stop! What on Earth could have caused that?
I was thinking: soft tyre - heavy landing - soft tyre cannot cushion shock - wheel hits ground hard - rim separates. But highly improbable, I grant you.
So what then would have caused a rim to break off.......badly corroded wheel? A cheap refurbished wheel reassembled incorrectly with the wrong bolts, or re-using the old bolts, or torqued incorrectly perhaps?
My suspicion is a maintenance issue in some form."
I would agree.
And if so - depending on whether or not FlyEgypt overhauls its own wheels - it may turn out to be grossly unfair to point the finger at the operator at all, in respect of the first incident.
Tabs please !
I remember that the PIA wheel fire incidents caused a few injuries to the fire crews called to deal with the flames. The slides were deployed and the fire crews stood at the bottom to assist the evacuating passengers. The problem was the combination of many of the older women being errrrr..... "big boned" and wearing silk. Unfortunately, silk has a rather low friction coefficient so they arrived at the bottom of the slide travelling considerably faster than anticipated. Due to good old half M V squared, a number of fireman required medical attention..
Last edited by B Fraser; 21st Oct 2021 at 06:04. Reason: grammar
When I say “shut it down” I don’t mean close the shop, I mean institute a safety shutdown.
I have to snigger when I read first-world pundits like Equivocal (who writes extremely well) suggesting a low-cost Egyptian airline conduct their own internal investigation. Clearly the learned gentleman has little to no exposure to Egyptian aviation ethics and morals, notably on the low-cost end of the line. What a hoot!
So by all means, jump on your moral bandwagons and chastise me for being overbearing in my concern and judgment. I will reserve my right to remain significantly concerned that when a low-cost Egyptian airline has 3 landing gear issues in one week in European locations that the holes in the cheese are lining up and bells should be ringing.
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You literally write "shut this airline down" in your opening post, even though you later try to water it down.
What happened to first figuring out what is causing this in the first place.... Axe to grind with this particular operator? Sure reads like it
What happened to first figuring out what is causing this in the first place.... Axe to grind with this particular operator? Sure reads like it
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I’ve never heard of, or had anything to do with Flyegypt. I certainly have no plans to ever engage their services. Any airline which has 3 related incidents in 1 week needs to be investigated. Urgently. That’s all I’m saying. You are welcome you maintain a liberal and tolerant stance.
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Let us know when you're prepared to show us the results of your investigation into the root cause(s) of these events and their contributing factors. Until then you have no more justification for saying they are unrelated than those who suggest they are.
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How about the fact I was a Mechanic for Western Airlines one of the airlines that placed an order for the 1st 737-200,s and worked on 737's for 41 years.
I have seen all of those results and know the reason.
I have seen all of those results and know the reason.
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With respect, and despite your vast experience, if you joined an aircraft accident investigation team and said "I've seen all those results and know the reason", you'd be the laughing stock -- among a team that has as much experience, or more, than you. In essence -- so you understand what an accident investigation tries to achieve -- you may indeed be exactly correct in the end about what happened, but that Sir, is not what an investigation is about. The "why" will be different each time, though some investigators, for example, would be looking more deeply at the potential of corporate organizational factors, or resources, or training, or corporate culture as root cause contributors when faced with several incidents at one organization in a short time frame.
I'm done here.
I'm done here.
Last edited by Sam Asama; 26th Oct 2021 at 05:38.
I think the most that can be said is that, based on the information available so far, 3 distinct and different failure modes occurred in a short space of time.
Whether or not, further back along the causality chain, there turn out to be contributory factors in common between the events is currently unknown.
Given that there doesn't seem to have been any announcement by either the Egyptian AIB or regulator that they are investigating a potential connection between the three events, we may never know the answer.
Whether or not, further back along the causality chain, there turn out to be contributory factors in common between the events is currently unknown.
Given that there doesn't seem to have been any announcement by either the Egyptian AIB or regulator that they are investigating a potential connection between the three events, we may never know the answer.
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"I think the most that can be said is that, based on the information available so far, 3 distinct and different failure modes occurred in a short space of time."
Thank you for explaining what I meant to say.
In my experience a tire that loses a recap or blows out is investigated by the manufacturer of the carcass. It's routine .
It happens often enough that it doesn't require a major investigation.
I've seen 4 broken rims.
Flat spotted tire are usually caused by the tires hydroplaning and not coming up to the minimum speed to allow the anti-skid to be active. I remember a day when I explained that to a pilot and when he questioned me I showed him 3 737-200's a adjacent gates all with flat spotted tires.
Thank you for explaining what I meant to say.
In my experience a tire that loses a recap or blows out is investigated by the manufacturer of the carcass. It's routine .
It happens often enough that it doesn't require a major investigation.
I've seen 4 broken rims.
Flat spotted tire are usually caused by the tires hydroplaning and not coming up to the minimum speed to allow the anti-skid to be active. I remember a day when I explained that to a pilot and when he questioned me I showed him 3 737-200's a adjacent gates all with flat spotted tires.
Since Egyptair's B738 has blown both nosegear tyres at Madinah, methinks certain HECA based nitrogen tanks should be checked for their actual content.
Maybe.
randomness is the way of the universe, and patterns that we are genetically programmed to search for, as are our SMS systems a la Doc 9859 AN/474 and our most revered teachings by the maters of linear causation, and of tasty cheese repurposing, Emmentaler, Gouda etc... The sad fact is the universe is stochastic, it doesn't follow much in a linear fashion, and while we put emphaisis on the past being a predictor of the future, well, that only is true to a limited extent. Ukraine shootdown didn't predict a B772ER loss 6 months later; 447 didnt glean much about it's future from 358, or 4590. 587 didn't gain much from 585, or 427. We are great at matrix, QA checklists and other accoutrements of the advanced safety systems we have developed, and they just ain't so.
Our safety would be better served by enhancing SA increasing displays and alerting systems, and teaching crews more on recognition of SA loss, and SA recovery techniques.
It is slightly specious, but Niels Bohr's comment " "Those who are not shocked when they first come across quantum theory cannot possibly have understood it." sums up the difference between a linear causation as ICAO, FAA, etc espouse, vs functional resonance and stochastic system behaviour, which is how the world really is.
Change doesn't have to be expensive; my jets use systems that were old when Armstong was kicking sand in a far off sandpit, yet my iPad, which gives head down synthetic vision with terrain awareness, HITS, and 3D traffic vision is only acceptable to the extent that it doesn't interfere with... what, a black and white FMSCDU display?
odd world we live in.
PS: Swiss cheese says more about the CO2 bubble formation in a lactose product than it does safety. lining up of "holes" happens in storybooks, not the universe we inhabit in the myriad of the multiverse. If you imagine a wave-particle (LMAO! ) behaviour around a slit of your philosophy's linear model, then you start to approach the non-linear functions that occur in the universe. Imagine that your rules cause a change to the vector of your "hole piercer" problem, that is, when manglement raise another incessant policy change, they act to change the path of all, a "butterfly effect" if you must. The crew then cope with a new reality caused by the changes in the policy, but that affects all, not just one slice of predrilled pecorino or parmesan. Linear models make bureaucrats happy as it simplifies their ticking of box solutions, but it doesn't meaningfully alter the likelihood of a future calamity. Things have improved, training, systems, and alerting have improved; TCAS, weather forecasting, hardware reliability, nav system accuracy... etc, so things are getting better. CRM? sometimes, but we don't teach SA and we spend little time on developing NDM heuristics, in fact, we essentially suppress the conditions where new crew gain such heuristics.
randomness is the way of the universe, and patterns that we are genetically programmed to search for, as are our SMS systems a la Doc 9859 AN/474 and our most revered teachings by the maters of linear causation, and of tasty cheese repurposing, Emmentaler, Gouda etc... The sad fact is the universe is stochastic, it doesn't follow much in a linear fashion, and while we put emphaisis on the past being a predictor of the future, well, that only is true to a limited extent. Ukraine shootdown didn't predict a B772ER loss 6 months later; 447 didnt glean much about it's future from 358, or 4590. 587 didn't gain much from 585, or 427. We are great at matrix, QA checklists and other accoutrements of the advanced safety systems we have developed, and they just ain't so.
Our safety would be better served by enhancing SA increasing displays and alerting systems, and teaching crews more on recognition of SA loss, and SA recovery techniques.
It is slightly specious, but Niels Bohr's comment " "Those who are not shocked when they first come across quantum theory cannot possibly have understood it." sums up the difference between a linear causation as ICAO, FAA, etc espouse, vs functional resonance and stochastic system behaviour, which is how the world really is.
Change doesn't have to be expensive; my jets use systems that were old when Armstong was kicking sand in a far off sandpit, yet my iPad, which gives head down synthetic vision with terrain awareness, HITS, and 3D traffic vision is only acceptable to the extent that it doesn't interfere with... what, a black and white FMSCDU display?
odd world we live in.
PS: Swiss cheese says more about the CO2 bubble formation in a lactose product than it does safety. lining up of "holes" happens in storybooks, not the universe we inhabit in the myriad of the multiverse. If you imagine a wave-particle (LMAO! ) behaviour around a slit of your philosophy's linear model, then you start to approach the non-linear functions that occur in the universe. Imagine that your rules cause a change to the vector of your "hole piercer" problem, that is, when manglement raise another incessant policy change, they act to change the path of all, a "butterfly effect" if you must. The crew then cope with a new reality caused by the changes in the policy, but that affects all, not just one slice of predrilled pecorino or parmesan. Linear models make bureaucrats happy as it simplifies their ticking of box solutions, but it doesn't meaningfully alter the likelihood of a future calamity. Things have improved, training, systems, and alerting have improved; TCAS, weather forecasting, hardware reliability, nav system accuracy... etc, so things are getting better. CRM? sometimes, but we don't teach SA and we spend little time on developing NDM heuristics, in fact, we essentially suppress the conditions where new crew gain such heuristics.
Last edited by fdr; 23rd Nov 2021 at 07:36. Reason: swiss cheese
The aircraft involved in the Cluj incident had been back in service for a week, following a couple of months parked and/or on maintenance.
The other two had been flying pretty well continuously throughout the year.
The other two had been flying pretty well continuously throughout the year.
