Sad Realization
- Thread starter Finhunter89
- Start date
jynxyjoe
Queso King
I dunno. The computer say flaps one, and 121 monkey sets flaps one...
Autothrust Blue
Welcome aboard the Washington State Ferries
We have flamage to the effect of:
Code:
--- DRY RUNWAY - PTOW ---
RWY MTOW MT CONFIG FL V1 VR V2 VFS
25R 7717 29 FLEX-T/O-2-ECS-ON 2 133 135 140 187@dasleben's whip has you retract the flaps at Vref30+(some knots), hence the R(__) blanks in his performance data I would assume (I don't really recall, it's been several type ratings of my own since I helped Dad study for 7ER school). Since flap retraction on the BroBus is a characteristic speed that the airplane itself dynamically calculates ("F-bug"), we don't bother with that, and instead produce V1, Vr, V2, and final segment (Vfs) speeds for entry into our TAKEOFF 3/3 page. The "CONFIG" flamage is entered for engine takeoff data; MT is our "flex" temperature and MTOW is the max takeoff weight approved for this configuration (divided by 10lb to fit nicely onto the line printer paper). And "FL" of course, is flaps/slats (2). There might be one more column on there regarding optimized V2, but its significance has not yet been explained to me, and I've never seen anything other than "N" there in the schoolhouse. "Will advise on that particular wart..."
Edited to make it say "FLEX-T/O-2," as that's what the thrust mode actually is.
Autothrust Blue
Welcome aboard the Washington State Ferries
We are directed by our SOP to select FLAPS 1 and use full takeoff thrust in windshear conditions, yes.
As far as what the "line" answer is, ask me in a month.
dasleben
That's just, like, your opinion, man
Autothrust Blue
Welcome aboard the Washington State Ferries
There are advantages to not notifying Moscow for performance, sir.
Polar742
All the responsibility none of the authority
Only when we're flying a mission.
Polar742
All the responsibility none of the authority
Autothrust Blue
Welcome aboard the Washington State Ferries
We do indeed, and I'm a fan.
ctab5060X
Well-Known Member
@PhilosopherPilot
Just to illustrate how two different carriers can operate the same airplane...
Over at US, we use Flaps 2 for almost every takeoff in the 190.
PhilosopherPilot
Well-Known Member
I'm not sure why we do it that way. Do you use Aerodata?
I know that Lufthansa uses Stall Prot Ice speeds on every approach. I wish we did. I hate how the plane feels when you are at normal approach speeds.
jtrain609
Antisocial Monster
Stall Prot Ice Speeds has got to be the stupidest thing I've ever seen in my life. On the -145 when you got SPS Ice Speed, the system would automatically adjust the AOA at which you'd get the shaker. No input from the pilot necessary, and no change in approach speed. On the JungleBus-175, Stall Prot Ice Speed can give you a ref speed of 160 on an 85 degree day in Houston because you banged through some ice in the top of a cloud while coming out of DTW.
It's tied with the yoke for the worst decision decision on the aircraft.
unclenobby
Well-Known Member
Seems like overkill to me by the Germans. Maybe they were having issues with people sending for normal speeds with STALL PROT ICE SPEEDS annunciated on the EICAS and dropping the bug too close to the yellow band.
unclenobby
Well-Known Member
Why is there no change in Vapp for SPIS on the 145? Or am I reading this wrong?
jtrain609
Antisocial Monster
You're not reading it wrong.
It's because it's not necessary. EMB realized with the -145 that the chances of you having so much ice accretion of the airframe that you'd need to fly 20 knots faster just to not fall out of the sky is not likely to happen, and thus, it changed the AOA slightly so that you'd get the shaker a few knots sooner than normal. They forgot this in the -175.
What's worse is that the wing and engine lip bleed valves would open for 1 minute in the 145, and they open for 5 minutes in the 175. It's like EMB became afraid of ice all of a sudden.
unclenobby
Well-Known Member
Does't the 170 basically do the same? The system automatically bumps up the caution and stall speeds thus a lower stalling AOA. It's up to the pilot to send for the appropriate speeds once SPIS is annunciated (that is you can send for normal speeds if you wish although I would not advise doing it!!)
I landed last week at Vapp 152kts full flap (almost max wind additive on top of ice speeds). I thought it was a little excessive however was glad when I saw plenty of ice on the H and V stab on the walk around.
jtrain609
Antisocial Monster
With the 170, at least at my shop, you've also got to send off to AeroData that the EICAS message popped up, which will then add 12 knots to your ref speed.
I get the idea of adding speed when you're flying a straight wing plane with boots, but a swept wing jet with everything that sticks out into the wind heated? The -145 never fell out of the sky because we flew our approaches at 1.3 Vso, and I'm not convinced the -175 would fall out of the sky either.
I think the difference is that EMB acquired Dornier's engineers to build the -175, and they had some different ideas about how things should be done.
I get the idea of adding speed when you're flying a straight wing plane with boots, but a swept wing jet with everything that sticks out into the wind heated? The -145 never fell out of the sky because we flew our approaches at 1.3 Vso, and I'm not convinced the -175 would fall out of the sky either.
I think the difference is that EMB acquired Dornier's engineers to build the -175, and they had some different ideas about how things should be done.
unclenobby
Well-Known Member
Exactly my point. YOU have to select ice speeds to get ice speed numbers in return, and YOU have to bug them! The airplanes brains (it has many!) has decided to increase stall speed/decrease stalling AOA as a result of detected ice accretion. You can send for whatever numbers you want and you can fly it at whatever damn Vapp you like!
I personally will side with the engineers, and increase my Vapp accordingly.
And like I said, plenty of ice on an unheated/unprotected and rather important rear control surfaces on my recent icing encounter on this gee whizz swept wing jet!