5 Things To Know About The No-Bleed Architecture On The Boeing 787

[@brianbeach3024]

One side effect is that the 787 doesn’t use an Air Start to start its engines when the APU is INOP. Instead, it needs a significant amount of ground power to accomplish this - I’ve seen stations need to hook up two separate gate powers plus a power cart just for barely enough power to get it going.

[@creativemindplay]

Seems that you work in the industry. Yes?

[@versasys]

The 787 always use 2 external power sources on the ground. The 3rd source is needed to start an engine if APU electrics are not available.

[@andykr2253]

@@versasys how does this work for power across the different buses? Like I’m assuming the load is split across the plugs and not just combined?

[@versasys]

@@andykr2253 L and R ext pwr is split. Google “boeing 787 electrical system diagram” to view an image of the electrical system diagram.

[@veowsaku]

We call this systems VFSG “variable frequency starter and generator”provided by the legacy team of Hamilton Sundstrand, each engine can generates up to 1MW of power as needed. The ground carts provide the electrical power to VFSG during the engine startup process and also provide the power to the all electric air conditioning packs. Using the ground support electric system the 787 does not waste any jet fuel until gate out.

[@gustavofernandez7178]

The 787 is a clean sheet design compared to the 777X. That's why 777X still uses bleed air.

[@tonamg53]

Actually it’s because it was a mistake. Remember 787 had battery fire problem when it was introduced? They never actually fixed that problem. They work around it by putting the whole battery compartment inside a vacuum chamber. So if the batteries short itself, it wouldn’t caught fire as there is no oxygen. You’ll just get annoyed passengers from IFE offline instead of emergency landing due to fire… Large amount of batteries bank would occasionally caught fire randomly… that is why they went back to using bleed air on 777x

[@bradw3116]

@@tonamg53Battery power has nothing to do with the bleed air system. As pointed out above, the 777X retains most of the systems of the previous generation of 777 due to type certification. Due to the extra power requirements of the 787 they use a lithium battery compared with the 777 using NiCad. Lithium batteries do carry a risk of fire due to their composition, and to mitigate the risk, Boeing have encased the batteries in steel boxes.

[@tonamg53]

@@bradw3116 Battery power got nothing to do with type certification. “Type certification” is to do with pilots training. Same type certification means pilot can train for the type and fly both model without needing to re-train. Pilots turn the power switch to “on” regardless of where it is getting its power from. Also here’s a fun fact… 787 share the same type certification as 777. Pilots can train for the type certification and fly both models.

[@bradw3116]

Quite correct on the battery power, that's why I said the bleed has been retained due to aircraft type certification. The aircraft type certification has nothing to do with pilots training, it's a regulatory process for proving the aircraft is satisfactory for commercial operation. The 777X is still going through this process

[@tonamg53]

@@bradw3116 787 and 777 share the same type certification. That’s a fact. The goal of gaining the same type certification is almost solely for training purposes. While they will look at how the system is design to gain the certification, that’s not the main objective nor it is the requirements for getting the same type certification. The main thing they will look into is that there are no significant differences in operating the aircraft… As long as the operations are the same, it can gain the same type certification.

[@holdingpointaviation]

Watching this whilst flying a B787 on a sim, I should've learned this before takeoff 💀

[@Patrickair4444]

So interesting feature of 787

[@collinsmwaura1833]

More-electric system architectures for flight controls could be viable in the years to come. Probably completely replacing hydraulic systems with Electromechanical Actuators (EMA). With the current advancements in DC power generation and distribution, high power brushless servo motor and actuators, computing, ethernet and fibre optics for flight controls , it is possible. Only that there isn't much venture into integrating these fields of engineering into one aircraft, mostly due to legal and economic reasons. 😉😉😉

[@princediego4673]

Please reduce the volume of the music. It competes with the narrator and reduces the quality of the video.

[@andrewdrone]

Yeah. Old music was better and less distracting

[@christiansta2771]

The no bleed can create $2.5k in fuel saving per flight if fuel capacity is maxed out.

[@tashagodspell]

Do you bleed? boeing 787: no, not really

[@creativemindplay]

😂😂😂😂

[@Tpr_1808]

😂😂😂

[@sainnt]

This video illustrates an example of why the 787 is outselling the Airbus widebody sector., and why Airbus has borrowed some of the design elements of the Dreamliner. The reduction in maintenance frequency saves airlines a lot of money, and it makes the 787 less costly to operate than the A350. Those savings really add up when you have a large fleet.

[@drdoolittle5724]

Are you sure 787 outsells the 350 on technical merit alone, for a start it is 4 years older and as Boeing is the USA's biggest dollar earner, all sorts of financial arm bendings are happening? Soon the World will see non-stop flights from Sydney to London fully loaded, something the 787 will never do economically!

[@sainnt]

@@drdoolittle5724 Let me tell you something interesting; Qantas currently flies nonstop from Perth to London with a 236 seat 787. They will be flying from Sydney to London in a 238 seat A350, burning way more fuel. How much more do you think they will make, assuming most of their first class passengers will be sitting there with points instead of cash? We'll see. Secondly, just because the A350 came later doesn't mean it's a more modern aircraft. Most of the A350 tech are from the A380, an aircraft that was developed in the 90's, and the A330 neo, an even older aircraft. The 787 has more advanced wings, more advanced fuselage, more advanced avionics, and more advanced engines replacing many of the bleed air systems with electrical ones, which saves airlines fuel and maintenance costs. So, to answer your question, yes, the 787 is outselling the A350 on technical merits.

[@bringbackmd7579]

​@@drdoolittle5724actually the The 787 is only 2 years older than the A350.. Program launch was April 04' vs December 06' for the A350.. Also ,some compromises were made for Project Sunrise. Initially, Qantas requirements were to fly 300 passengers, economically for the route.. Subsequently, will actually be fitted with 240 seats for the flights.

[@CheapBastard1988]

Reduction of maintenance frequency is overrated. Because with the 787, whatever is reduced in maintenance, is paid back with more repairs. Where I work, every 787 has a weekly maintenance visit in an effort to keep the number of Defered Defects down and preventing AOGs. An effort that is slowly failing.

[@sainnt]

@@CheapBastard1988 I'd believe that if we weren't talking about an aircraft that's been in service for over a decade. The maintenance I'm talking about here is the engines, and those are the most expensive components. The 787 requires much fewer maintenance cycles than the Trent XWB, and it's not insignificant when you compare both aircraft. While the A350 and 787 are both clean sheet designs, the 787 is still a more modern aircraft, so yes, there are definitely issues related to being the first of anything, but most issues having to do with the 787 have been mostly resolved. There's not much a planemaker can do about issues being caused by outsourcing except to deal with them.

[@drdoolittle5724]

Has anybody proven whether everything advantageous is actually meaningfully true? Like flying a weighed 787 and identical A350 from Perth to London at the same time??

[@jwil4286]

I wonder if Boeing would ever put this tech on their narrow bodies

[@Apollo580]

That would require them to completely redesign the 737 or do a clean sheet design new narrow body. Which they would never do.

[@ivangeo3319]

Make that electrical power not turn off because engine malfunction, for example.

[@dalecooper9942]

Is it similar to blood diamonds?

[@tomg6284]

Just don't put lithium batteries in it. Fire hazard extreme.

[@il400]

well all planes have some batteries, not Li,; what is your point? the power is provided by generators

[@RealGaryGibson]

I'd like to know why Boeing didn't go no-bleed on the 777X.

[@PlanesAndGames732]

Probably for extra commonality with the older 777s

[@AnarchyEnsues]

Because they would have to spend even more money redesigning all systems instead of just the wing, engine and a few other systems.

[@nahteo]

Short term stock concerns

[@FanRailer]

Bc the 777x isn’t a clean sheet design.

[@michaelmoses8745]

The 777x isn't a clean sheet design.

[@normanmcleod7169]

What happens in the event of an electrical failure ... is the aircraft still controllable?

[@skyserf]

One type of backup for electrical failure in a 787 is a Ram Air Turbine. The RAT can produce electricity and hydraulic power.

[@CheapBastard1988]

​@@skyserfAlso, both engines have two starter generators, the APU has two starter generators, and the Electronic Engine Controllers have their own dedicated generators. And then there are two batteries (main battery and APU battery). The 787 has more electrical backup systems than most other aircraft. Besides that, the left and right hydraulic systems still have old fashioned Engine Driven Pumps. It's not like there aren't any hydraulics without electrical power. It's just that the center hydraulic system is dependant on electrical power, while a 777 would also have Air Driven Pumps on the center system.

[@abeygeorge1588]

The question that should be asked, if it was so efficient, why isn’t it being used on the 777 max? A plane built after the 787.

[@dusabederrick5634]

The 787 is a clean sheet plane where as the 777x is not a clean sheet plane

[@OmarEwert]

This was a pretty bad explanation of bleed air

[@bikingmoments]

Why A350 didn’t go this route already indicates this isn’t the best route - battery fires etc are disadvantages

[@SRT-fv6wr]

What rock did you just crawl out from under ..?? Obviously ,been solved.. 10 years on, and no issues since..

[@bikingmoments]

@@SRT-fv6wr solved by Boeing ONLY… why would Airbus take this additional risk when they were already under a rush to make this clean sheet design A350??

[@CheapBastard1988]

​@@bikingmomentsTo prevent tiny amounts of engine oil vapours from entering the cabin would be a good reason. There's a reason other aircraft need a high power test run after an engine wash.

[@collinsmwaura1833]

Lithium-Ion Battery fires and bleedless system architectures have nothing to do with each other.

[@abababa7483]

All that electricity would need to be generated by some heavy gernerators, so I fail to see the weight savings.

[@joeljustin]

The electrical power is generated by the engines itself. Making use of this electrical power directly for discreet systems saves on weight and complexity.

[@bikingmoments]

@@joeljustin you do need more and/or stronger generators to convert engine spinning to electricity. It’s more efficient than pressurized air for sure, and does save some weight.

[@randomyoutuberthotslayer8247]

Generators used in Aviation operate at much higher frequency, so they are not that heavy. Boeing did the calculation and then arrived at the architecture.

[@CheapBastard1988]

The two VFSGs (Variable Frequency Starter Generators) on a single engine have a similar weight as a the single IDG (Integrated Drive Generator), BUG (Backup Generator), and airstarter (including ducting) like is typically found on a 777s' GE90 engine.

[@davidyoung3288]

we know electric car has less repair; in 2023;