Quoting queb (Reply 41): ground vibration testing is now completed.

I don't get it, why was this not completed before first flight? Nothing has changed structurally since then and they have flown the aircraft to M 0.6 without having 100% grip on the bending modes of the wings and airframe??

I find this hard to believe, there is something they have seen in this third flight that makes them go back and redo the tests with more thorough analysis of certain bending modes and frequencies.

To me it has a certain smell of problems. It could also be BBDs test method to do it in an iterative way but then I need others to give examples of other projects that have stepped forward in such an iterative way. To me the bending modes and frequencies and the aerodynamic forces shall have been clear before the third flight, that they then see for instance aero loads that differ is possible but then they should only need to re-run their models to understand if they are approaching flutter ground, not re-run the vibration tests.

[Edited 2013-10-16 22:18:59]

Quoting queb (Reply 41): ground vibration testing is now completed.

Story on Flightglobal:

http://www.flightglobal.com/news/art...s-ground-vibration-testing-391806/

Quoting ferpe (Reply 43):

They might have adjusted the FE calculation based on flight test results on the "known" part of the flight enveloppe.
The ground test might be needed to recheck the code on the "unknown part" of the flight enveloppe
Having say that, i'm not convinced... they could have used ground vibration sets from the initial tests for that

Sounds strange

Quoting KarelXWB (Reply 32): Look what I found:

Thank you. That puts in nice graphical form (and numbers) why the C-series has pushed both Boeing and Airbus to update their narrowbodies. It also highlights why the SSJ isn't selling so well...

Quoting KarelXWB (Reply 28): They have the iron bird working since 2010, although it was not connected to Aircraft Zero until February 2013.

Thank you. The 2010 is the important date. Early software debugging while building off a known good architecture:

Quoting ferpe (Reply 30): since then they have cleaned out all the old non conforming "I ex SNIAS/MBB do it my way" rubbish. That means all work with the same system architecture, tools and digital models since the 350.

   I think it also helped having done so shortly after the A380. In other words, the staff is experienced. But this has gone so much better than the *same* work on the A380 I suspect there are a few individuals who helped push through better standard work as a lessons learned.

Quoting LH707330 (Reply 36): I could see them punting on EIS, but in 2020 everyone will look at it as a solid plane.

Agreed. The hardest part for Bombardier will be selling the first 300 airframes to set up economies of scale (e.g., MRO network) and debug the design. Once it is proven, it should sell nicely. I agree with your timeframe (unfortunately, as I am a HUGE C-series fan). I think Bombardier could accelerate that a bit... but could and will are two different verbs...

Quoting airmagnac (Reply 39): Maybe it's simply a more general issue of inexperience in how to handle quick modifications to the highly integrated systems.

And probably how to debug before the sub-systems are integrated...

Quoting airmagnac (Reply 39): without data networks and feedback loops and all those migraine-inducing things.

Tell me about it...

Lightsaber

Program update from Rob Dewar, CSeries program manager. First CS300 fuselage will arrive later this month.

http://www.youtube.com/watch?v=JwkhQDDEgdw

Quoting queb (Reply 47): Program update from Rob Dewar, CSeries program manager.

Everything looks great except they have flown 3 times in 30 days, that does not look good at all. Why is he not addressing the questions that everyone is asking, why are they on the ground doing stuff that everyone thought they had behind them??

And why is he talking about doing shimmy and vibration tests, they did these before a delayed first flight, why again????

Edit:
I checked around and found this sentence from Leeham news which can explain the shimmy part, but how can indoor vibration testing be delayed by rainy weather   , on the contrary, if they can't fly for another week they have more time for indoor testing  

"We understand that the long run of rainy weather in advance of the first flight (delayed by a week because of the weather) meant that some of the testing that had been expected in advance of the flight resumed after the flight."

[Edited 2013-10-17 11:38:34]

Maybe because Bombardier had invited more than 70 carriers for the first flight happening and they could not postpone.

Quoting queb (Reply 49): Maybe because Bombardier had invited more than 70 carriers for the first flight happening and they could not postpone.

Absolutely, that I buy. Now how can that influence indoor testing? Do you mean they invited these people at short notice because they saw a gap in the weather (which was not good and they had to aim for a hole that appeared) and therefore did the first flight without having completed all first flight preparations? That I would buy but then BBD should have told people to expect a pause in the flight test program to complete these test. They did not. Their behavior is then as mysterious as their tactic around first flight, to give very specific dates and then miss them.

Learn from Airbus, they say summer for first flight and fly in June and then 2H for first deliverym when they deliver we will see but they have given themselves 6 months to keep word. That is the right type of communication, not "before the end of June 2013" stated in Dec 2012   is not IMO.

One more video on youtube today (Oct 17th), this one the "ESIM" engineering simulator.

http://m.youtube.com/watch?v=k_e0Je-iIds

I saw today on my iPhone in the stock news that Bombardier is in advanced talks and fleet/business model planning with numerous airlines. All this has been since the first flight. I wonder when these may turn to orders. Apparently in the last week or so they have had 60+ airlines/lessors in for a visit during an ICAO assembly.

I don't have the link at the moment, if anyone can add it that would be great.

Jamie

Is it possible that they deferred some of the testing for the transonic regime to after the first set of flights? Sort of pull in the first flight date by limiting the max speed to about M0.6 and only doing the required ground vibration tests needed.

Since they were not going to expand the envelope to M_MO and beyond or V_D/M_D for any flutter testing, get the first flight out of the way to appease everyone?

Quoting golfradio (Reply 52): Is it possible that they deferred some of the testing for the transonic regime to after the first set of flights? Sort of pull in the first flight date by limiting the max speed to about M0.6 and only doing the required ground vibration tests needed. Since they were not going to expand the envelope to MMO and beyond or VD/MD for any flutter testing, get the first flight out of the way to appease everyone?

This is fully possible, and seems to be supported by the following FlightGlobal story:

http://www.flightglobal.com/news/art...n-next-cseries-test-flight-391852/

"Dewar also noted that the aircraft remains in ground vibration testing, even though Bombardier said last June that such testing had been completed.

The previous round of ground vibration testing simply cleared the FTV-1 for first flight, says Philippe Poutissou, vice-president of marketing for Bombardier Commercial Aircraft. The second round will allow Bombardier to proceed into envelope expansion flights.

“It was a decision of sequencing that we made earlier,” Poutissou says on the sidelines of the Canadian Aerospace Summit in Ottawa.

FTV-1 demonstrated in the first three flights the stability and control that Bombardier expected, Poutissou says.

The aircraft flew all three flights in direct mode, meaning that the normal fly-by-wire control system has so far not been activated. The next round of flight tests will begin examining the normal mode of the fly-by-wire system, in which the flight computer commands the control surfaces based on inputs by the pilot.

“We are getting ready to fly the aircraft higher, faster and at a different [centre of gravity],” Poutissou adds."


The thing I don't understand in such case is why they don't say that after the third flight, it would stop all speculation that something is fishy. Once again their communication strategy is the least impressive part of the program   .

Quoting golfradio (Reply 52): Is it possible that they deferred some of the testing for the transonic regime to after the first set of flights?

Quoting ferpe (Reply 53): “It was a decision of sequencing that we made earlier,” Poutissou says on the sidelines of the Canadian Aerospace Summit in Ottawa.

Thanks for a most logical question, golfradio, and for the official update, ferpe.

Although it seems that progress is at less than a snails pace, I would rather BBD get it right the first time, rather than having to bandage hiccups later.

Quoting ferpe (Reply 23): I think it is time for some aviation Journalist to ask BBD why things are progressing so slowly.

I concur. Something isn't adding up, not if they really have the same flight test schedule as the A350. Oh, we can agree the A350 is a more complex plane that has additional testing required for the far ETOPs operations.

Quoting ferpe (Reply 53): Once again their communication strategy is the least impressive part of the program

Again, I concur. But the schedule of testing does not match the goals. Not if BBD is going to achieve ETOPs at EIS.

Quoting ferpe (Reply 53): The aircraft flew all three flights in direct mode,

  That implies a software debugging process *far* behind schedule. I hope I am wrong...

Note: I worked for a company that found out the cost of flight testing was cut *dramatically* doing the first flight in normal mode. So I'm a wee bit biased. But man did that force early debugging of the flight control software. Once it was pulled off by one project, all other projects were benchmarked against that and found to be too expensive in comparison for little to no risk reduction. But that is an opinion based out of the culture I came out of and I see why Bombardier is doing what they are doing.

Lightsaber

Per Twitter reports, China's CDB Leasing signed a conditional purchase agreement for 5 CS100 and 10 CS300 aircraft, plus 15 options.

[Edited 2013-10-18 05:17:39]

Quoting KarelXWB (Reply 56): Per Twitter reports, China's CDB Leasing signed a conditional purchase agreement for 5 CS100 and 10 CS300 aircraft, plus 15 options.

And here is the press release:

http://www.bombardier.com/en/media-c...rdierdisclosescdbleasingcoltd.html

Quoting KarelXWB (Reply 57): Quoting KarelXWB (Reply 56): Per Twitter reports, China's CDB Leasing signed a conditional purchase agreement for 5 CS100 and 10 CS300 aircraft, plus 15 options. And here is the press release:

Most excellent!   

I didn't see in your link the conditions. I would assume performance related, but is there more?

Lightsaber

At last a Chinese order! Its been speculated for a long time and with the tie-up between BBD and Comac I've been expecting more orders from China.

There is some outdoor activity again.

http://twitter.com/sylvainfaust

Quote: FTV1 currently towed to usual road 408 for engine runup

The nice thing of the CDB Leasing deal is that they appear to have increased the total, as the "original" conditional order did not include options.

Quoting ferpe (Reply 53):

I agree...BBD totally sucks at communicating...not just flight test details...but anything. It seems like they are very paranoid of releasing information which may be contradicted at a later time...but it also seems like they get so caught up in the nuts and bolts of their project, that they forget about all the people interested in the program.

I suspect that prospective customers are very up to date with the program...but journalists, pundits, self proclaimed aviation experts and we enthusiasts, are left in the dark to guess and speculate.

It makes sense to me that the first few flights were in direct mode. If you really want to gauge aircraft performance parameters, it seems cutting a system out of the loop which would probably mask any inherent problems, is a good idea.

None of this, though, quells my curiosity one iota. I want these things blotting out the sun, dammit.

Quoting JoeCanuck (Reply 62): I suspect that prospective customers are very up to date with the program...but journalists, pundits, self proclaimed aviation experts and we enthusiasts, are left in the dark to guess and speculate.

I really don't think that BBD really cares about those of us outside of the aviation industry who have a enthusiast curiosity about the aircraft.

Quoting brilondon (Reply 63): Quoting JoeCanuck (Reply 62): I suspect that prospective customers are very up to date with the program...but journalists, pundits, self proclaimed aviation experts and we enthusiasts, are left in the dark to guess and speculate. I really don't think that BBD really cares about those of us outside of the aviation industry who have a enthusiast curiosity about the aircraft.

Unless you are a major shareholder asking for updates. The immediate success of the program hinges on the success of the testing. The immediate long term success depends on orders. The much lesser and not urgent is the curiousity of Aviation Fans and to some extent the public. John Q public is not watching for every inch of movement nor keeping track of how many hours in the air. John Q or in other words the masses will be the one's flying on the aircraft to large extent. Unless there is a massive problem with large scale advertising, to the public no news is good news.

Quoting brilondon (Reply 63): I really don't think that BBD really cares about those of us outside of the aviation industry who have a enthusiast curiosity about the aircraft.

Keep in mind that this is a publicly-traded company, listed on both the Toronto and New York Stock Exchanges. They have to be very careful what they say publicly, and equally careful about what they DON'T say publicly.

With that in mind, understand that if anything is happening with the test program that constitutes a "material event" -- i.e. it would affect the company's financial performance and influence the market, driving the share price (in either direction),they are required to disclose that in a timely fashion or risk the wrath of the OSC and the SEC -- not to mention the potential for shareholder lawsuits. IMHO a major delay in the development of the CSeries would be a material event, given the amount of money invested and the impact on the aerospace division should they incur penalties (for late delivery) or, worse, lose customers.

What that possibly means is that no news is good news. Don't bet money on it, though.

Quoting Arrow (Reply 65): Keep in mind that this is a publicly-traded company, listed on both the Toronto and New York Stock Exchanges.

BBD is not listed on the New York Stock Exchange. Many people assume that it is. However, being listed on the New York Stock Exchange had been an objective of Paul Tellier who was Bombardier's President and CEO from 2003 to end of 2004.

Quoting planemaker (Reply 66): BBD is not listed on the New York Stock Exchange.

Oops -- you're right. Shouldn't make logical assumptions. Doesn't change the reporting rules, though.

Quoting arrow (Reply 67): Doesn't change the reporting rules, though.

It does as the NYSE requirements are "stricter" than the TSX... but that is not saying too much. In any case, most people are simply not aware just how "managed" the "reporting" actually is in relative comparison to the public's perceived strictness of the rules. One only has to look at the MBS fiasco (among several) as just one mere example.

Anyone watching/owning BBD-B.TO stocks must really like today....they are up 19 cents (and were up 9 cents on friday). Not a huge amount, but it's the 3.35% that is nice!

I think an educated guess would have this stem from the Chinese leasing company announcement last week.

Any guesses as to what airlines in China or that part of the world might be interested in the CSeries? I don't think there has been a detailed discussion of this yet...

Jamie

Quoting jalarner (Reply 69): I think an educated guess would have this stem from the Chinese leasing company announcement last week.

They just announced a firm sale of 30 Learjet85 to Flexjet, I guess this explains today's rally.

According to the article, Iraqi Airways will be ordering 5 x CS300's from Bombardier.

Link: http://www.iraq-businessnews.com/201...et-authorises-bombardier-contract/

I guess with this order, Iraqi Airways will not take delivery of the 4 remaining CRJ900's that they placed some years ago. Hopefully Bombardier will be able to find new buyers for the CR9's soon.

Sounds like the CSeries is starting to gain some traction and it will be interesting to see if Lion Air and Qatar Airways order any before the year is up.

Cheers,
CRJ900X

Quote: But we’re told by a source familiar with the program, but who is not with BBD, that BBD is being conservative in its pace, counting on the fact that it will eventually have seven FTVs to bring entry-into-service on time. A few Canadian aerospace analysts think EIS will slip to 1Q2015.

Whole article:
http://leehamnews.wordpress.com/2013...is-tide-ready-to-turn-for-cseries/

Quoting CRJ900X (Reply 71): I guess with this order, Iraqi Airways will not take delivery of the 4 remaining CRJ900's that they placed some years ago. Hopefully Bombardier will be able to find new buyers for the CR9's soon.

Don't they have enough routes for the last four CR9s? Are those four CR9s already built and stored? If not, no money loss for BBD, I would think.

Great if Iraqi goes for the CS300, can't wait to see that bird fly.

Quoting CRJ900 (Reply 73): Are those four CR9s already built and stored?

Yes, they are on the tarmac just beside the FAL.

FTV1 next flight will be fly-by-wire in "Normal Mode".

http://twitter.com/sylvainfaust/status/392728944916439040

Quoting KarelXWB (Reply 75): FTV1 next flight will be fly-by-wire in "Normal Mode".

the real question is not "how" but "when"

CSeries Awaits Fly-by-Wire ‘Upgrade’ Before Flying Again
http://www.ainonline.com/aviation-ne...aits-fly-wire-upgrade-flying-again

Thanks for sharing the article. Still no real answers though.

And a small update on FTV2:
http://twitter.com/sylvainfaust/status/392752908405469184

Quoting KarelXWB (Reply 77): Thanks for sharing the article. Still no real answers though.

Which is a bit disappointing, but they must have their reasons for it. Hope she will fly again soon.

Quoting queb (Reply 76): Quoting KarelXWB (Reply 75): FTV1 next flight will be fly-by-wire in "Normal Mode". the real question is not "how" but "when" CSeries Awaits Fly-by-Wire ‘Upgrade’ Before Flying Again http://www.ainonline.com/aviation-ne...again

Here a fair excerpt:

"In an interview with AIN last Friday, Bombardier Commercial Aircraft marketing vice president Philippe Poutissou said the CSeries would fly again once engineers finished an upgrade to its Parker Aerospace fly-by-wire flight control system to allow the airplane to operate in “normal” mode. Test pilots flew the airplane in so-called direct mode during the first three flights, without the full aid of the fly-by-wire system.

“It’s been part of the design of the flight test to do that first bit initial assessment on the direct mode, and the next block of testing I believe we will be going into normal mode,” said Poutissou. “So we have to basically roll [out] that software on the fly-by-wire.”


It makes you wonder why they would need "normal" mode to go beyond M 0.6 and higher then FL250. I think it has to do with damping. It should mean you can't activate yaw damping (which would be the most essential damping) in direct mode, which I find a bit strange. But it could also mean they were not sure of the damping parameters and needed both aero and resonance mode data to tune the so called inner loops of a FBW system. In a FBW system the inner loops contains the damping and any flight angle and angle of attack limitations. The outer loops are the auto flight modes like attitude, vertical speed, altitude and M hold etc.

In this case I think the important parts are the damping loops, as you fly faster then M 0.6 you came into areas where things like dutch roll (to low yaw damping, to stiff natural damping in roll) comes into play. Also when you go higher the natural aerodynamic damping of the fin etc decays and you once again face yaw instability, dutch roll tendency etc.

So it seems it is the un-familiarity with the FBW which causes this fly, analyse and tune, fly, analyse and tune to be so much slower compared to the FBW pro Airbus and Boeing.


Edit: for those who wonder what Dutch roll is, read here:
http://en.wikipedia.org/wiki/Dutch_roll

The other mode which could cause trouble when going faster and higher up would be the short mode pitch oscillation but that shall normally be well enough damped for a test pilot to fly the regime. It is later a certification criteria that you can do without pitch damping I think, not sure about yaw damping. The long term phugoid and spiral modes are not causing any trouble, those you fight every day when you fly a Cessna or Piper, this is called "keep the altitude and wings level for gods sake" ie you are the damper  .

[Edited 2013-10-23 00:12:53]

Quoting jalarner (Reply 69): Anyone watching/owning BBD-B.TO stocks must really like today....they are up 19 cents (and were up 9 cents on friday). Not a huge amount, but it's the 3.35% that is nice!

Yes I'm happy with recent gains   . Still, though I'm looking more long term for BBD. I feel like the stock is quite under-priced given the potential for the Cseries. We'll have to wait and see if the program can fulfill it's potential, (which I think is huge), but either way, the market is showing some "787 based anxiety" which I feel are de-valuing the Cseries and excessively-weighing down BBD's stock price. I hope I'm right, but who knows at this point.

So new ground vibration test could have been with FBW on and dampening on also ?

Quoting Aviaponcho (Reply 81): So new ground vibration test could have been with FBW on and dampening on also ?

Not quite sure. It would not have been for the whole time, you want to collect the fundamental structural bending modes and resonance frequencies first to udpate your dynamic structural model. Once you have done that you might do a next step with damping in the loop but I doubt it. The damping is normally not set to dampen the structural modes (the 748 is an exception where this was used for certain wing flutter damping) but the aerodynamic oscillations I described (which would be lower frequency and larger amplitudes). If your inner loops are required to dampen structural things they have to work very hard and you would get maintenance issues IMO. The 748 only uses it for very specific short duration patches of the flight envelope, then it can we useful as it is not working all the time.

It was a while since I was involved in FBW so I am not sure, perhaps someone else can chip in.

Clear is that you take the results from aero testing (both CFD, small and real world windtunnel) and then tune your damping respones. Then you check that your damping does not excite or gets affected by any of your structural modes by putting the damping into the structural model together with the aero oscilations. That is why you need both an close tracking aero and structural model and might be why BBD has divided the testing like this as they got real world aero data in the 3rd flight which helps with this final tuning of the dampers.

FTV1 taxied to the start of the runway:
http://twitter.com/sylvainfaust/status/392996655584120832

But an issue prevents her from flying:
http://twitter.com/sylvainfaust/status/393004029531271169

Quoting ferpe (Reply 79): It should mean you can't activate yaw damping (which would be the most essential damping) in direct mode, which I find a bit strange

Please don't get me wrong, I am not questioning but just trying to wrap my head around this and learn.

I am trying to understand the link between the yaw dampers and the FBW mode. Shouldn't yaw dampers be independent of the flight mode i.e. always on or off depending upon whether engaged or not? Yaw dampers would be working off their own gyros or yaw accelerometers and then act on the final output of the rudder deflection. The final output of the rudder deflection will be the result of the FBW mode (no filtering in Direct mode versus filtering in Normal)?

Also why wouldn't the yaw dampers be needed below M0.6?

Quoting golfradio (Reply 84): Please don't get me wrong, I am not questioning

Don't get me wrong  , it was ages since I dwelled on this stuff and I am on thin ice   so you should put in question what I write  , further I am speculating as to what BBD is doing and why...

Quoting golfradio (Reply 84): I am trying to understand the link between the yaw dampers and the FBW mode. Shouldn't yaw dampers be independent of the flight mode i.e. always on or off depending upon whether engaged or not? Yaw dampers would be working off their own gyros or yaw accelerometers and then act on the final output of the rudder deflection. The final output of the rudder deflection will be the result of the FBW mode (no filtering in Direct mode versus filtering in Normal)?

It used to be like that, you had a mechanical control system and the damping with gyros was on top. In modern FBW you double for redundancy but not for function, thus the rate gyros serve both damping, inner loop limiters/modifiers/filters and any outer loop functions. I therefore think that when the BBD marketing guy says we will use "normal" mode everyone thinks "aha with the envelop protection and such". I don't think that is the case, I would not like to fly a first flight into M > 0.6 with such stuff active but I could very well take the dampings and some frequency filters which prohibits structural resonances to mess up my FBW (my gyros pick up fuselage deflections and interpret it as aircraft movements). So to me normal mode means some necessary damping and filtering active to increase safety and observability of real dangerous stuff, see below.

Depending on how direct mode is made you are fine in direct controlling the control surface up to a certain speed and altitude. Then as things go faster low down you come into PIO area, as you go higher your yawn damping weakens and you risk dutch roll. PIO is not fun at all but a test pilot is trained to let go of the stick to stop it, dutch roll is just unpleasant and before it goes to far your are off throttle to dampen it.

As you really chase any signs of flutter and make very special control inputs to exite and detect that (steps, sweeps, .....) you don't want the other stuff to show up at the same time, it can delay any flutter boundary detection and then it gets dangerous.

Re damping at lower speeds, generally the movements are slower and you can intervene as a pilot, you are in phase (PIO is when you are opposite phase  ) .

But as said, skating on thin ice.....

FTV1 didn't make it into the air today.

FTV2 is online.

http://twitter.com/sylvainfaust/status/393113801060388864/photo/1

Damnit. I keep seeing planes over my house and think that it's FTV1 :P Just a few minutes ago, a twin-engine jet is over the house as I exit the car. I come into the house and open planefinder.net to see what it was, but FTV1 is quietly sitting at YMX. That said, I haven't figured out what plane it was, it just seems that there's either a very big delay, or some planes just don't show up on there.

Quoting ferpe (Reply 85):

Thanks ferpe. I'll chew on this for a while.

Quoting ferpe (Reply 85):

Good stuff...thanks.

Quoting KarelXWB (Reply 86): FTV1 didn't make it into the air today.

Too bad, hope they will get the flight test and certification process on the way (or better; in the air  ) as soon as possible.

Quoting JoeCanuck (Reply 90): Good stuff...thanks.

Yeah, ferpe is teaching us all a lot. Such posts are so interesting to read, though as just an aviation enthusiast sometime I do not grasp all he is posting, but I am quite convinced he is correct in his postings.  

Re a typical FBW system and it's different modes I did a bit of checking after the last post. The Airbus FBW does not have the yaw damper active in direct law, they do have variable pitch gain however, this is to reduce the risk of Pilot Induced Oscillations, PIO.

Reducing the pitch gain (lowering the amount of elevator you get for a certain stick movement aft and forward) with speed is a standard way to regulate that the elevator gets more powerful the faster it goes and you finally enter a domain where you sneezing can make the pax sit in the roof . Then there is also the risk that you come in anti-phase with the aircraft with your reactions to any disturbance and you have PIO, which is dangerous if the pilot does not let go of the stick.

So I would believe the Cseries FBW does not have yaw damping in direct mode and might have no or very crude pitch gain control with speed (or really q, dynamic pressure, which is density of air * speed^2 ). Then I would like to have "stripped" normal mode as well for extending the envelope  .