Forum menu
How so? Genuinely interested.
Well, if you ignore the fact that six of them are flying around with condemned fuselage sections and Boeing doesn't know which ones they are...
There are some odd decisions made solely to hold a common type rating with the 777. It runs the same flight guidance software and is already running out of memory (I think the database has to fit into 4MB). The 777 CDU is drawn graphically but instead of quickly jabbing one of the buttons with your finger you have to click on it using a mouse. It's just a wasted opportunity. There is no logical flow to anything because, y'know, this is how it worked 40 years ago.
Automation drives controls and switches through solenoids and servo motors, instead of controlling the system directly and then reflecting the state by back-driving the switch. Why is this an issue? If the switch breaks you lose complete control of the system in question.
Other bizarre engineering decisions? There's no system to directly track flap or slat position - it's derived from the drive mechanisms. So, for example, if ice builds up behind a slat the whole mechanism will shear when commanded to move but the asymmetry won't be detected by the computer.
The electronic checklists are rudimentary and can only sense the condition that triggers them, so you might get conflicting checklists for complex failures. The standard of English is simply appalling (plenty of double negatives, for example. Or not being able to continue the fuel leak checklist until you've answered "no" to the question "fuel leak is suspected"). We're told it's because it has to be understandable to non-native speakers.
Good stuff?
Fantastic wing. Normally the max altitude is limited by the wing. This isn't an issue on the 787. The load alleviation function in turbulence is very effective.
The idea of a common core network and fibre optic data network is clever and, in general, works well. LED lighting throughout.
The autopilot is capable, but agricultural, as is the autothrust.
Been through severe turbulence and an overspeed with no damage.
The lower cabin altitude is great. The seats are relatively comfortable.
Is there nothing built into the drive motors for the slats and flaps that detect excessive resistance and backoff either informing the cockpit or not?
Well, if you ignore the fact that six of them are flying around with condemned fuselage sections and Boeing doesn’t know which ones they are…
😳
Ah well that’s ok then
Well apparently it is....unless I've missed something those photo's showing F4 Phantoms with a significant portion of their wings folded (not just wingtips) they are flying perfectly in a safe and controlled manner. On the 777X it is only the very tip of the wing that folds - like I said before they're not really contributing significantly to lift and are devices intended to reduce drag and improve efficiency.
Other bizarre engineering decisions? There’s no system to directly track flap or slat position – it’s derived from the drive mechanisms. So, for example, if ice builds up behind a slat the whole mechanism will shear when commanded to move but the asymmetry won’t be detected by the computer.
Don't believe this for a second. All aircraft have to have feedback loops on flap track systems to detect asymmetric flap configurations and there is a whole procedure in every aircraft flight manual around the warnings for asymmetric flap extension. Where are you getting this information from? Back in the day when I worked in aircraft manufacture (Bae systems) they all had LVDT's on the flap track lead screws to track flap position as well as the fact that each of the flap track drive shafts are configures in series, so all connected so all move in unison so if one section has an issue or is restricted then the whole system will hang up and trigger a warning. There is also a rate of deployment monitors so if one wings flaps are deploying more slowly than the other for some reason then it triggers an alarm and kicks in a fail safe protocol. Also each drive shaft goes through a gearbox in between each section, and the input/output speed of the gearboxes is monitored to detect sheared drive shafts or drive shafts exhibiting excessive twisting...really around flaps and slats there is so many monitoring and safety measures that are well embedded in the systems design requirements. There is no way a bit of ice...or indeed alot of ice, is going to hang up the drive mechanism.
Well, if you ignore the fact that six of them are flying around with condemned fuselage sections and Boeing doesn’t know which ones they are…
Again, where are you getting this from? Working in the aerospace industry myself I know that this is impossible. We have to demonstrate continued airworthiness of all our kit flying globally all the time. If we couldn't identify and locate 'condemned' equipment (not even sure what condemned means...not a properly defined term in the industry - it would be categorised as Unserviceable) then our entire fleet would be grounded immediately...no excuses...the airworthiness certificate would be withdrawn immediately and any aircraft in the air told to divert to the nearest airport. So under what jurisdiction or alternative means of compliance is Boeing using that allows any 787 to fly with unserviceable fuselages?? I'm not aware of any that would allow an OEM or airline to continue to operate any bit of equipment that might be unserviceable. Aircraft have been grounded before because the serviceability status of nuts and bolts couldn't be confirmed. Literally every part of an aircraft has complete back to birth data right back to the mines the metals were mined from, the machines and equipment involved at every stage of manufacture of every single component...everything, so a major failure of back to birth record such as you describe would lead to instant withdrawal of the aircrafts Certificate of Airworthiness. There is just no way on earth any 787 would be flying in such circumstances as you suggest.
Are these merely fake news on aviation forums? I suspect so. I've worked all my proffessional life in the civil aviation industry and, these two items in know from my own experience cannot be true.
Well apparently it is….unless I’ve missed something those photo’s showing F4 Phantoms with a significant portion of their wings folded (not just wingtips) they are flying perfectly in a safe and controlled manner.
"It didn't crash" is not the same as "it"s not an issue", surely?
Re: the rest - Flaperon writes more authoritively than you.
An Israeli pilot landed an F15 with one wing missing. Doesn't mean that they only need one wing.
like I said before they’re not really contributing significantly to lift and are devices intended to reduce drag and improve efficiency.
You’re very hung up about the ability to fly in the wrong configuration. My initial thinking was actually about them hitting things on the ground
I thought what Flaperon was referring to was perhaps the Terrible Teens? MSNs 10-20 which suffered significantly from early production process and had significant structural problems in the centre-wing box area. These aircraft 6-7 of them, sat at Everett for years after requiring substantial modifications which increased their weight and decreased their range by about 20-25%. The aircraft were indeed grounded until modified.
I also thought that flap position was monitored by LVDTs and feedback sensors on the worm drives, but this is also based upon knowledge/experience from Airbus and BAE.
Well, if you ignore the fact that six of them are flying around with condemned fuselage sections and Boeing doesn’t know which ones they are…
There's also this: https://www.corporatecrimereporter.com/news/200/john-barnett-on-why-he-wont-fly-on-a-boeing-787-dreamliner/
I think I'll stop reading this thread now otherwise I'll have to tell my employer why I'm not going to the states next week.
Between that and Pickle Forks on 737's to Cyprus and Menorca later in the year I'll be lucky to see Christmas.
@wobbliscott You'd think there would be additional protection to detect asymmetry following a shear of the drive mechanism, but apparently not. If you work on the 787 you'd know there's a bulletin covering the problem.
It doesn't go into particular technical detail about why the asymmetry isn't detected. I find it hard to believe the thing was built without a secondary source of position information independent from the slats drive mechanism (there's a primary, secondary and alternate system), so my best guess says it's possibly a software issue at the end of the day.