can you increase speed to 210 KIAS for the next 2 minutes?

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Antoine
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can you increase speed to 210 KIAS for the next 2 minutes?

Post by Antoine » Sat Aug 31, 2019 10:04 am

Another fun story from the LSGG Geneva arrivals library!

The other day we were incoming from the west at FL 230 to take advantage of a nice tail wind.
The Extra 400's cabin altitude is 7'000 ft at this level and I normally prefer it lower due to my strange oxygen saturation issue (I need oxygen from 8000 ft). So I normally file FL190-200 and give up a 6-7 knots in return for a 5000 ft cabin.
But the tail wind was great at altitude (actually FL230 is not so far way from the tropopause, so you sometimes find a nice influence form jetstreams.

So I decided to climb and surf along!
Climbing above FL 180 in a turbocharged piston single is a lot work. You need to watch four parameters that become limiting in the rarefied air:
- Inlet air (how hot the air that is ingested by the engine gets) , which creeps up as the turbo works harder and harder to compress the air
- Oil temperature: I think my aircraft's oil cooler needs an overhaul, the fins are damaged by years of ingesting water and insects.
- Coolant temperature
- Airspeed

So the deal is: reduce power (manifold pressure) to keep inlet air temperature at 130 F maximum
Proactively reduce climb rate to keep at least 110 KIAS for cooling
Temporarily reduce climb rate further if oil temp is creeping too fast.

It is a complex task, but very rewarding and once settled in cruise all temps get back to green in no time at all.
Economy cruise at FL 230 is a nice 196 KTAS and with a tail wind component of 50 knots you can do the math !

We arrived so much earlier than our slot that ATC decided to give us shortcuts, further accelerating our arrival. This also squeezed us in a sequence of big iron traffic.

This time I knew what was coming and was preparing for an extremely fast intercept and ILS.

Sure enough, we were kept high and given a shortcut to INDIS, perfectly aligned with the ILS... at FL 190.
We went through the Arrival and Approach checklists in sequence and I mentally switched to "high speed ops".
I warned my passengers that at some point they might hear a loud horn as I chopped power to slow down.
When cleared to descend, I dialed in 1500 ft/min and kept cruise power. The Extra accelerated with the usual rock-solid feel - the only noticeable clue was the nose down attitude and a change in the tone of the prop blast.

As we intercepted the ILS, we were doing over 230 knots true, and 193 KIAS. GS was even more.

And then this radio conversation happened:

N121AG: N121AG established ILS 04
ATC: N121AG say speed
N121AG: one-niner-three AG
ATC: N121AG can you increase to 210 for next 2 minutes?
N121AG: (...) unable AG
ATC Roger N121AG keep 190 to six and call tower 118.7

Actually 210 indicated was doable - VNE is 219 KIAS.
Avionics won't let me dial-in more than -1600 fpm. So I would have needed to hand fly and point the nose down for maybe 2500 ft/min.
I decided against it because of the following:

1. I was high and was almost certain that Tower ATC would eventually ask me to slow down while descending steeply.
2. 188 KIAS is the limit of the green arc and I was expecting turbulent air lower. I did not want to commit to 210 and then make a fool of myself by reducing speed due to turbulence.
3. It just felt wrong to push the plane so hard and I said to myself: "If you goof by 10 knots you'll hit Vne..."

And so I had to swallow my pride and say "unable". But the reward came seconds later

Tower: Hello N121AG, number 2, reduce speed to 160 to four miles...

Phew - I was glad we were not 20 knots faster.

With more and more practice, I now kind of enjoy having to dump energy in this aircraft.
The only issue is once you have the gear down, (140 KIAS) you should not plan on reaccelerating.
So I do not use the gear as an airbrake until 2 miles out.
This leaves the prop. The ability to chop power at will thanks to the liquid cooled engine turns it into a very effective airbrake. One only needs to know that the combination of low power AND gear down causes a massive loss of energy- Intercepting the glide slope requires some practice but it is very rewarding when it works smoothly.
I have found max RPM and 17 inches to be a good engine setting for final. It allows a gradual speed decay to 80-85 KIAS which is what I want to see when crossing runway threshold (depending upon loading).
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Tommy
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Re: can you increase speed to 210 KIAS for the next 2 minutes?

Post by Tommy » Sun Sep 01, 2019 8:17 pm

Hey Antoine. How’s it going? I had a similar experience going into Chicago Exec. (KPWK.) ATC wanted to know if I could keep my speed up (184 ias) for a visual approach No.1 into runway 34 in front of an Embraer. No problem I told ATC. It was somewhat of a nail biter going that fast so close to KPWK. However, in hind sight it was a blast. Four miles out they gave me to the tower who promptly told me to, in their words, “slow down.” It was great.
Yeah, energy management is a trip at those speeds when you’re so close. Throttle, flaps and gear on short final in that order. It’s amazing how fast you can slow down within a few miles with sequence and timing. Fun stuff.
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Re: can you increase speed to 210 KIAS for the next 2 minutes?

Post by jb642DA » Sun Sep 01, 2019 8:25 pm

What kind of plane were you in, doing 184ias, Tommy?? Your profile shows a DA40???!!!
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Re: can you increase speed to 210 KIAS for the next 2 minutes?

Post by BRS » Sun Sep 01, 2019 8:28 pm

jb642DA wrote:
Sun Sep 01, 2019 8:25 pm
What kind of plane were you in, doing 184ias, Tommy?? Your profile shows a DA40???!!!
Notice Tommy's reference to "Throttle, Flaps, Gear".

Tommy, I wonder if APR was having fun with the TWR using you as a dart to see if they could dodge it.
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Re: can you increase speed to 210 KIAS for the next 2 minutes?

Post by Tommy » Sun Sep 01, 2019 8:48 pm

Aerostar. Yeah, I wouldn’t doubt it. They were really trying to cram everybody in quickly.
Antoine
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Re: can you increase speed to 210 KIAS for the next 2 minutes?

Post by Antoine » Sun Sep 01, 2019 9:49 pm

Heyyy Tommy nice to see you again here. I tried to PM you. I wanted to connect you to a new friend who almost bought an Extra 400 and then backed off and went for ... an Aerostar 700P.
I flew with him and was very impressed.
Since then he has criss-crossed Europe and then taken his plane across the pond to the "factory" for annual.
The Aerostar really is mind-blowing fast, especially the landings! ... but the complexity of this 700P made me think "it's two E400s bolted together!" Two engines, each with two turbos, pressurization and so many peripheral systems the instrument panel did not have enough room for all the gauges and switches!

How are your two babies doing? Any more PIREPs?
My Extra is doing great, going in for a 100 hour next week... absolutely love it! I have started posting youtube videos
https://www.youtube.com/watch?v=3GMHESSNzNU
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Tommy
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Re: can you increase speed to 210 KIAS for the next 2 minutes?

Post by Tommy » Sun Sep 01, 2019 10:04 pm

Hi Antoine, just got back from the Aerostar factory myself a couple of weeks ago. I actually had a chance to fly the jet. 4,000’ a minute climb with 241 ias at 15,000 msl and it wasn’t even breathing hard. It’s really not even like flying an airplane. Very quite and so ridiculously smooth. Lots of energy management involved. No props to slow you down.
Both planes continuing to go through the renovation process. It’s pretty much non ending with me. Believe it or not, I consider it fun. It’s almost like collecting antique cars. 1969 and 1976 were really good years for me. The airplanes are a continuing reminder of those times. I’m having a lot of fun.
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Re: can you increase speed to 210 KIAS for the next 2 minutes?

Post by jb642DA » Mon Sep 02, 2019 1:48 pm

BRS wrote:
Sun Sep 01, 2019 8:28 pm
jb642DA wrote:
Sun Sep 01, 2019 8:25 pm
What kind of plane were you in, doing 184ias, Tommy?? Your profile shows a DA40???!!!
Notice Tommy's reference to "Throttle, Flaps, Gear".

Tommy, I wonder if APR was having fun with the TWR using you as a dart to see if they could dodge it.
BRS -
I am aware it wasn't a DA40 - that's why I asked "What kind of plane were you in, doing 184ias, Tommy?? ". Also, thanks for pointing out the "Notice Tommy's reference to "Throttle, Flaps, Gear"." for me!


Tommy - Thanks for telling me it was an Aerostar!
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