Guest topsy1970 Posted September 18, 2003 Share Posted September 18, 2003 Good day! I am no airline pilot but I have flown many many times as a passenger on different products. I am just curious with regards to what I assume is called the climb power setting. In most AC that I have been on there is a slight reduction of power a minute or so after take-off. This seems to be a smooth transition on most AC. However, I have noticed on numerous occasions with the A321 there is a very abrupt power reduction. To the point of people lifting their heads and looking around for 2 or 3 seconds as if we just ran out of gas. Then everything is back to normal. Is this normal? Also, the plastic molding inside the fuselage creaks and cracks quite a bit around the wing area during turbulence. Is this because the AC is new? Thanks, just curios... Link to comment Share on other sites More sharing options...
Guest Saltaire Posted September 18, 2003 Share Posted September 18, 2003 Interesting point........basically the airbus ,321 included, has auto-thrust and it's thrust levers are operated in detents or fixed positions depending on the phase of flight. This eliminates the more gradual movements of the thrust levers and therefore the smoother transition of power. Having said all this I believe the thrust can still be transitioned from take-off power to climb power with a more smoothly and deliberate hand. I have noticed the same thing at AC and it would obviously be prudent to the concern of the passengers and the engine for that matter to pull the power back more slowly than yank it from one detent to another. The airbus is made of lighter and more composite materials and the wing is constructed to flex to withstand a variety of flight conditions so although it might feel not as solid as some of the Boeing products it is a very safe and reliable aircraft. I like your first point and am glad you brought it up. Cheers Link to comment Share on other sites More sharing options...
Guest PortTack Posted September 18, 2003 Share Posted September 18, 2003 From deadheading a lot I've noticed this several times in the 319/320/321, however I've also noted when the power adjusts very smoothly as well. Is there a way to 'finess' this. Link to comment Share on other sites More sharing options...
Guest Max Continuous Posted September 18, 2003 Share Posted September 18, 2003 >> although it might feel not as solid as some of the Boeing products << You mean because it was built by a wine sipper with a glue gun and not a beer guzzler with a rivet gun? Link to comment Share on other sites More sharing options...
Guest Sawbones Posted September 18, 2003 Share Posted September 18, 2003 "Is there a way to finess this?" Absolutely! Link to comment Share on other sites More sharing options...
Guest PortTack Posted September 18, 2003 Share Posted September 18, 2003 So what causes the more than occasional after-take off "oh-sh&t-we-ran-out-of-gas-I'm-gonna-lose-my-lunch-feeling"? Is it the dreaded lazy pilot thing we can all suffer from or a software glitch? Honestly curious as I've wondered what the heck it is for while now....but been to lazy to ask;) Link to comment Share on other sites More sharing options...
Guest RJP Posted September 18, 2003 Share Posted September 18, 2003 The more significant thrust reduction comes when YYZ ATC does not give you higher than the SID departure altitude of 5000 ft. Usually when there is someone inbound at 6000 ft. The lighter the aircraft, the more abrupt the change as you approach 5000 ft at 250 kt and 4000-5000 feet per minute. Suddenly your at thrust idle and leveling. Sometimes you can translate that energy into speed when cleared to accelerate, but usually you are restricted to 250 kts. YYZ is probably the best example of leveling off after take off, although there are some others. Link to comment Share on other sites More sharing options...
Mitch Cronin Posted September 18, 2003 Share Posted September 18, 2003 Could it be partly that when it's really abrupt someone hadn't used enough flex temp, and was using more take-off thrust than necessary? Whatever, the end result, for some poor sods in the back, is that the loss of acceleration feels like deceleration, and without an airspeed indicator back there, I could swear the airplane's about to do a belly flop. So I'm with Topsy1970... either figure out how to make it smooth, or have us install a bunch of airspeed indicators in the back! We had this conversation a while ago and I thought you all promised to be smooth? Link to comment Share on other sites More sharing options...
Maranatha Posted September 18, 2003 Share Posted September 18, 2003 Mitch, you want SMOOTH, go fly on one of Mr. Boeing's products, preferably the 767. Link to comment Share on other sites More sharing options...
handyman Posted September 18, 2003 Share Posted September 18, 2003 I believe, it has everything to do with the design of the thrust levers or whatever Airbus calls those things again. The fact that they don't move when the autothrottles are engaged leads me to believe the change to climb thrust is like flicking a switch and it feels about that abrupt. Mr. Boeing uses motors to move the thrust levers with autothrottles engaged and thus it takes 2-3 seconds for the change. As an interesting side point, we now conduct TO2 take-offs (B744) or a 20% reduction under set conditions which actually creates a power increase at the climb thrust point. Link to comment Share on other sites More sharing options...
Mitch Cronin Posted September 18, 2003 Share Posted September 18, 2003 Airbus calls it "autothrust", but even with the detents, i'm pretty sure that if the fellas bring back the sticks slowly from the TO/GA detent to the Climb detent...(or whatever that next one is) the engines follow the lever, as smoothly as commanded. I've just been looking through my "differences" books and I can't find anything that would indicate the 321 is any different than the 320's or 319... Interesting re your increase to climb! That sure would feel better! Link to comment Share on other sites More sharing options...
handyman Posted September 18, 2003 Share Posted September 18, 2003 OK, it was a poor guess but it doesn't matter because "I ain't goin". Link to comment Share on other sites More sharing options...
Homerun Posted September 18, 2003 Share Posted September 18, 2003 Just make sure you bring a mechanic with you. Link to comment Share on other sites More sharing options...
Guest Saltaire Posted September 18, 2003 Share Posted September 18, 2003 Correct!! I think the guys just should be alot more deliberate and smooth from one detent to another. Link to comment Share on other sites More sharing options...
Pierre Garneau Posted September 19, 2003 Share Posted September 19, 2003 I try to take about 5 seconds from FLEX to CLB, and almost double when TOGA (or full power) is required for take-off. Otherwise, I agree with other contributors, it feels like you stood on the brakes. I have watched weary passengers look at one another with that 'what's wrong' look when the thrust is 'snapped' to the next detend. Link to comment Share on other sites More sharing options...
Pierre Garneau Posted September 19, 2003 Share Posted September 19, 2003 I try to take about 5 seconds from FLEX/MCT to CLB, which makes the transition pretty smooth. Double that time for TOGA to CLB (2 detents). I was deadheading once and a few people looked at each other when thrust was abruptly reduced with that "what's wrong' look. Pierre Link to comment Share on other sites More sharing options...
BoomerPete Posted September 19, 2003 Share Posted September 19, 2003 Sorry dude ... it's just less than optimum technique by the individual operator. Anyone who wants to can make the thrust change on a bus just a smoothly as on a Boeing. As a guy who's spent plenty of time on both the A's and the B's I found that the 757, especially using climb 2, had a far more pronounced "shot out of the sky" sensation than either the 320 or the 330. Pete Link to comment Share on other sites More sharing options...
Guest shibui Posted September 19, 2003 Share Posted September 19, 2003 or, for a real thrill, try a 777-300 at 286 tons and 42 degrees OAT. When climb thrust is set it feels like you've been shot down.... Link to comment Share on other sites More sharing options...
MCDU Posted September 19, 2003 Share Posted September 19, 2003 I suspect that the abrupt power change they're talking about is not when CLB is selected at 1500ft, but A/T commanding idle when leveling off at the SID altitude of 5000. Therefore, the time taken between detents is not relevant. As for finesse- some pilots revert to V/S before ALT*, some take the A/T off and make a more gradual reduction, some leave the automation alone. BTW, Mitch, we normally use as much FLEX as the WAT charts will allow, and that wouldn't affect the power change leveling off at 5000'. Link to comment Share on other sites More sharing options...
Mitch Cronin Posted September 19, 2003 Share Posted September 19, 2003 Thanks MCDU... I might have known... I guess I'm just not good at being a passenger, in any vehicle. I could probably stand the less than one G stuff a little better if I knew you fellers could handle the recovery, but hey, I watch the movies. I know what goes on up there with you and "auto". (ok, ok, I'm just kidding!) Cheers, [snicker choke snort giggle] Mitch Link to comment Share on other sites More sharing options...
MCDU Posted September 19, 2003 Share Posted September 19, 2003 Dude! I'll have you know that I did unusual attitude training when I was a B744 F/O. (Now that was fun!) Besides, the Erbus wouldn't let me have an upset. (Would it?) ;-) Link to comment Share on other sites More sharing options...
Mitch Cronin Posted September 19, 2003 Share Posted September 19, 2003 Glad to hear that. I imagine that would be a gas! Re: "Would it" Ahh, but it will! You just have to convince the dude behind you (in the sim) to let you pull enough CB's... then .... over she goes! Mind you, motion was off when I did that... might be a rather pertinent point!... and oh ya, everything froze up just as I reached 180 degrees of roll but any less and all was well. (well, considering... ) Link to comment Share on other sites More sharing options...
MCDU Posted September 19, 2003 Share Posted September 19, 2003 Sim? My tongue was planted firmly in cheek, you can see lots of weird stuff on the actual airplane. ;( After 6 years across our entire bus fleet I know enough to always keep the little red button within thumb's reach. Link to comment Share on other sites More sharing options...
Mitch Cronin Posted September 19, 2003 Share Posted September 19, 2003 Zounds!! ... I'm just now remembering a coupla guys with question marks embedded on their foreheads who, upon being asked, "how's your airplane" began to try to explain the thing telling them they'd just found the "Alpha Floor", while they'd been otherwise happily doddling along in cruise. Odd beasts, these compu-planes! I'll never forget the 310 that swore to me the gear was up while I was being pushed out of the hangar!... Or another odd duck that insisted the box was just fine while refusing to start the APU.... Of course a new box (ECB) fixed that.... You folks with some time on these electron-filled-fly-by-magic birds could probably make a few bucks writing stories! Cheers, Mitch Link to comment Share on other sites More sharing options...
MCDU Posted September 19, 2003 Share Posted September 19, 2003 What bothers me most is the misconception some passengers (and some other employees) have that it's all automatic. Even when it all works, it's far from that. Don't get me wrong, when everything's kosher, it's a really nice airplane. But, when something goes wonky, all hell can break loose, and a pilot really earns his cash by understanding what's going on and what to do about it. Unfortunately, instead of simplifying the operation, a whole new layer of complexity has been added. A false sense of security can be suddenly shattered by a dual FMGC failure, or a reversion to Direct Law (controls). Your Alpha Floor example is perfect. There are many other examples of completely unexpected behaviour- some of the funky reversions that can happen under certain circumstances of capturing altitudes. I recently had the airplane suddenly apply TOGA power and start climbing while I was in Idle Open Descent, capturing an altitude and making a speed reduction well above Vls. Airbus says "there's always a reason," but sometimes you just say "WTF" and disconnect. I'm starting to ramble, but I suppose what I'm trying to say is that flying an Airbus is like owning a Rottweiler. You pat his head and let him sleep in front of the fireplace, but you never leave him alone with your kids. Link to comment Share on other sites More sharing options...
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