Matt2218

Simulating the 900ER / Derated Takeoffs

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Hello!

I recently made the jump from FSX to P3D and bought the NGX (again, LOL).

Are you guys flying the -900 much? If so, do you have any rules of thumb for setting assumed temperature for derated takeoffs? I have TOPCAT...any way to use that (ie extrapolate downward from 737-800 results or something?).

Also, I recognize that the 900ER has greater capability due to higher weights and more exits, but otherwise the 900 flies like a 900ER (assuming the short field package option is selected), right?

I'm not obsessed with 100% fidelity with the 900 model, just looking to fly it like a 900ER on shorter routes with some degree of realism. Welcome your thoughts...

 

Matt Smith

 

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The reason I have a copy of TOPER for the 737 is the -900.  It only gives ATM and not derate but it is good enough for simulation.

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There's also QSimPlanner which I use and it's freeware. Does more than just takeoff performance, too.

Why would the short field package make it more like a 900ER?

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Nah, the -900ER does not fly like a straight -900.  There's grumbling when you pull paperwork and see you're in an old -900, especially if it's windy ;-).

Therein lies the biggest difference - approach speeds are significantly inflated on the -900 for tail strike protection, so with flaps 30 + wind additive on a gusty day, target speed can be well into the 150s, which puts you close to flap overspeed/blow back. 

The ER fixes this mostly artificially, with a two-position tailskid that extends with the gear, but there are definitely aerodynamic changes too... the straight -900 flies like a truck, the -ER has a much nicer feel. 

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32 minutes ago, Stearmandriver said:

Nah, the -900ER does not fly like a straight -900.  There's grumbling when you pull paperwork and see you're in an old -900, especially if it's windy ;-).

Therein lies the biggest difference - approach speeds are significantly inflated on the -900 for tail strike protection, so with flaps 30 + wind additive on a gusty day, target speed can be well into the 150s, which puts you close to flap overspeed/blow back. 

The ER fixes this mostly artificially, with a two-position tailskid that extends with the gear, but there are definitely aerodynamic changes too... the straight -900 flies like a truck, the -ER has a much nicer feel. 

 

Thanks Andrew, good to know but also kind of disappointing.

After spending $120 to get effectively the same FSX product I already had for this new sim, I wouldn't be offended if PMDG threw in the -900ER or the raindrops etc. as a bennie for loyal customers, even this late in the game.

Edited by Matt2218

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23 minutes ago, Matt2218 said:

 

Thanks Andrew, good to know but also kind of disappointing.

After spending $120 to get effectively the same FSX product I already had for this new sim, I wouldn't be offended if PMDG threw in the -900ER or the raindrops etc. as a bennie for loyal customers, even this late in the game.

Don‘t hold your breath... the NG3 is in development, I personally doubt there will be any updates to the 737NGX of this kind.

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21 minutes ago, Ephedrin said:

Don‘t hold your breath... the NG3 is in development, I personally doubt there will be any updates to the 737NGX of this kind.

 

Indeed...not actively hoping for or expecting anything.

 

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4 hours ago, Matt2218 said:

Are you guys flying the -900 much?

Honestly, the 900 is complete bull**t when it comes to ground handling. Luckily the last airline flying is gone here. This AC is tail tipping just by looking at it, it's so fast on its back, that the caterer cant caters in the fwd galley until you have at least 50 pieces in the 3.

(maybe company procedure). even though its annoying as hell.

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15 hours ago, SierraHotel said:

I use ToPs, and gives everything I need for a derated takeoff.

https://secure.simmarket.com/tops-takeoff-performance-system-fsx-p3d.phtml

Can't believe I've never heard of that tool before.  Does it work pretty well,  and do the takeoffs feel realistic (flight deck angle, v1 stop distance and such). It's cheap enough I'll get it anyway.  Just never heard of it before 

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15 hours ago, 30K said:

caterer cant caters in the fwd galley until you have at least 50 pieces in the 3.

This should surely be the other way around? Can't cater the aft galley unless there's some in 2?

I presume I ought not to show you the Delta tail tipping video then? 🙂

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17 hours ago, Stearmandriver said:

Nah, the -900ER does not fly like a straight -900.  There's grumbling when you pull paperwork and see you're in an old -900, especially if it's windy ;-).

Therein lies the biggest difference - approach speeds are significantly inflated on the -900 for tail strike protection, so with flaps 30 + wind additive on a gusty day, target speed can be well into the 150s, which puts you close to flap overspeed/blow back. 

The ER fixes this mostly artificially, with a two-position tailskid that extends with the gear, but there are definitely aerodynamic changes too... the straight -900 flies like a truck, the -ER has a much nicer feel. 

Do you as an actual pilot like flying the 900ER? I've read some reports of pilots not being so happy with it, mainly because it's so prone to tail strike and makes rotation and flaring 'uncomfortable'.

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17 hours ago, threegreen said:

There's also QSimPlanner which I use and it's freeware.

QSim only gives you a choice (a wide range - a wild guess) of assume temps - no derates. I think the OP is looking for a utility that TELLS them derates and assumed temps like topcat does.   

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18 hours ago, SierraHotel said:

I use ToPs, and gives everything I need for a derated takeoff.

https://secure.simmarket.com/tops-takeoff-performance-system-fsx-p3d.phtml

 

3 hours ago, sosuflyer said:

Can't believe I've never heard of that tool before.  Does it work pretty well,  and do the takeoffs feel realistic (flight deck angle, v1 stop distance and such). It's cheap enough I'll get it anyway.  Just never heard of it before 

 

28 minutes ago, pracines said:

QSim only gives you a choice (a wide range - a wild guess) of assume temps - no derates. I think the OP is looking for a utility that TELLS them derates and assumed temps like topcat does.   

Paul is correct - I was looking for something that would just spit out a temp for me. Since it was only about $7, I went ahead and grabbed that TOPS utility from simmarket.

It seems pretty basic and TBH that is what I was after...something better than just firewalling full TOGA all the time or blindly guessing. I think it is very clever how it reads location and weather data from the sim and provides the answer without much need for manual intervention.

Thanks for the replies and tips!

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1 hour ago, threegreen said:

Do you as an actual pilot like flying the 900ER? I've read some reports of pilots not being so happy with it, mainly because it's so prone to tail strike and makes rotation and flaring 'uncomfortable'.

I do like the ER.  It's obviously not a short field bird, but it flies nicely.  The tail strike threat is real, but manageable without much issue as long as you fly the plane the way it needs to be flown. 

If you have the HUD, you have a direct indication of tail strike attitude, and that helps a lot. Our entire fleet has the HUD and captains are required to use it during takeoff and landing in the -800s and -900s for just this reason.  So for me as an FO, I don't have that indication, but knowing that someone does is reassuring.  I can also say that I've seen captains rotate a -900 much more aggressively, and flare much more deeply, than I would have felt comfortable with (and much more than was necessary), and we've not had a problem.  Obviously they're more comfortable with it because they can watch the tailstrike indication... but the takeaway for me is that crews who accomplish a tailstrike managed to get themselves into a pretty goofy aircraft state in order to do it.  It's not exactly something that can just "happen" if you're maintaining a normal attitude and energy state. 

That said, we've had crews do it just like every other airline, so I never say never.  There is a gotcha situation that can develop in certain configurations / energy states during landing, where spoiler deployment (probably combined with the reversers opening) can cause the aircraft to pitch up alarmingly, and that's caught people by surprise.  I've seen it, and it requires prompt forward pressure to keep the nose from pitching up.  I could definitely see this being an issue, especially for someone relatively new to the plane, combined with a night or low vis scenario with poor horizon reference etc.  But again, hopefully the guy monitoring the HUD sees it developing in time to stop it. 

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As far as straight -900 approach speeds go, I just did this.   6,000ft runway (1,000 displaced threshold), winds gusting in the 30s, ref of 151kts with a 14kt wind additive, for an approach speed of 165kts.  Max autobrakes required on a dry runway.  Straight -900s are dumb ;-).

afLW0A5a_o.jpg

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1 hour ago, Stearmandriver said:

That said, we've had crews do it just like every other airline, so I never say never.  There is a gotcha situation that can develop in certain configurations / energy states during landing, where spoiler deployment (probably combined with the reversers opening) can cause the aircraft to pitch up alarmingly, and that's caught people by surprise.  I've seen it, and it requires prompt forward pressure to keep the nose from pitching up.  I could definitely see this being an issue, especially for someone relatively new to the plane, combined with a night or low vis scenario with poor horizon reference etc.  But again, hopefully the guy monitoring the HUD sees it developing in time to stop it.

This would be one of those gotcha situations I guess... https://www.youtube.com/watch?v=viFR1qRPKs4

 

12 minutes ago, Stearmandriver said:

As far as straight -900 approach speeds go, I just did this.   6,000ft runway (1,000 displaced threshold), winds gusting in the 30s, ref of 151kts with a 14kt wind additive, for an approach speed of 165kts.  Max autobrakes required on a dry runway.  Straight -900s are dumb ;-).

Thank you very much for the replies. I actually got myself in a situation like that in the sim recently and wasn't sure if the target speed with the wind additive I calculated (close to + 20 kts) was even permissible. It also put me uncomfortably close to the flap 30 limit speed. Looking forward to the NG3 which will hopefully include an actual 900ER.

Edit: Is it allowed to actually use flaps 40 at that weight with a target speed that high? I assume you were carrying fuel for a return trip to be that heavy on landing?

Edited by threegreen

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7 hours ago, threegreen said:

This should surely be the other way around? Can't cater the aft galley unless there's some in 2?

I presume I ought not to show you the Delta tail tipping video then? 🙂

Ehm yeah. Clearly, I had a long day 🙂

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16 minutes ago, threegreen said:

This would be one of those gotcha situations I guess... https://www.youtube.com/watch?v=viFR1qRPKs4

 

Thank you very much for the replies. I actually got myself in a situation like that in the sim recently and wasn't sure if the target speed with the wind additive I calculated (close to + 20 kts) was even permissible. It also put me uncomfortably close to the flap 30 limit speed. Looking forward to the NG3 which will hopefully include an actual 900ER.

Edit: Is it allowed to actually use flaps 40 at that weight with a target speed that high? I assume you were carrying fuel for a return trip to be that heavy on landing?

Yeah, that is the "gotcha" situation - it's related to the minor bounce you can see, which would not be bad but in a certain energy state can cause the spoiler deployment to create a pretty good pitch up.  You can see he didn't touch down in a tailstrike attitude, the plane pitched into it after touchdown. 

Boeing recently revised guidance on wind additive to cap it at 15kt maximum regardless of conditions, so that helps some. 

We just had some alternate fuel on board, certainly not enough for a return trip, I think we landed with around 10.7.  There's no restriction on using flaps 40 at any weight, the problem is twofold because of the conditions: it exacerbates the effect of crosswind and gusts, and provides even less leeway before hitting blowback speed.  

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3 hours ago, threegreen said:

 

Edit: Is it allowed to actually use flaps 40 at that weight with a target speed that high? I assume you were carrying fuel for a return trip to be that heavy on landing?

No weight limit. Flaps 40 in gusty conditions is usually a bad idea - especially in a straight -900 as they are even closer to a blowback.

I was flying a -900 last fall and the FO kept getting close to the flap limit and I was calling his speeds so we didn't exceed the limit. He got the plane on the ground, nice landing. No exceedences. Next leg is mine. Of course on that leg, I'm the one who gets the blowback. Sigh.

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10 hours ago, Stearmandriver said:

for an approach speed of 165kts.

A bit of MD11 feeling 🤣🤣

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