Slow flight - CPL Prep

[milotron]

Hi, for the new year year I am committing to finishing my CPL. 

One of the biggest challenges that I have always had is getting the Mooney slowed down to slow flight speeds in level flight. Part of the issue I have had is the local practice area is fairly small: it works fine for a 172 at 90 kts but at 120 kts you cross it in about 1.5 minutes.

I have typically resorted to dropping the gear for any kind of stall or slow flight work.  Is this typical? How do you folks setup for this kind of airwork?  My instructor is well versed in high wing C's and twins, less so for higher performing singles.

Thanks

iain

[milotron]

We have a lot of controlled space in our area. The practice areas are defined airspaces for this purpose. Getting to uncontrolled space requires filing a flight plan ( greater than 50 miles ) and is doable, just more planning. The club does this for Multi training for similar reasons; a block of airspace over the ocean that is generally unused.

I am flying a turbo, so different settings, and can make this work fine. Getting it slowed down in preparation for the slow work in a way that looks controlled and organized in the eyes of the flight tester is what I am after.

I did the written test a year ago and have all of the ground work and flight times in, just down to final prep for the flight test. I was planning on doing it in a 172 as I was somewhat concerned about wear and tear on the plane ( I have to use the 172 for the spin portion anyways ) but would really rather hone these skills in my plane.

iain

[Vance Harral]

The most experienced instructors I've worked with don't seem to particularly care what configuration is used for slow flight: clean, flaps only, or flaps and gear are all OK.  The FAA commercial pilot ACS (do you use this in the Great White North?) doesn't require any particular configuration for the slow flight task, so it really is the pilot's choice... in theory.  In practice the examiner may have preferences on the check ride, so it behooves to you to talk to him in advance if possible.

That said, the ACS does require the "landing configuration" for power-off stalls and "takeoff configuration" for power-on stalls.  Since both of these require gear down, and since slow flight work is often combined with stall work, I typically fly slow flight with the gear down.  I also tend to set the flaps to the "takeoff" position, since this reduces the required pitch attitude to maintain level flight at low speed.  You can certainly fly slow flight in the clean configuration, but the higher pitch attitude required to do so is less comfortable, and can have a negative impact on cooling.

[milotron]

17 minutes ago, bluehighwayflyer said:

Sorry. I thought your avatar was a 201. I'm currently on my phone and the image is very small. Of course then our power settings will be very different. 

You have to file a flight plan, too, to fly more than 50 miles away from your home base?  That makes me appreciate owning my own plane and living in a rural area. 

OK. Sorry I couldn't help. Best of luck in finishing up your CPL. 

Jim

Thanks, you too!

 

In  the controlled space at my base, a distinct code from ATC is required just to take off for a local ( 50 miles or less ) flight.  A flight plan needs to be filed if farther than that. Lots of radio work in my area!

Farther up the island you can out in 1200 and do what you want, but not where I live.

 

iain

[milotron]

8 minutes ago, Vance Harral said:

The most experienced instructors I've worked with don't seem to particularly care what configuration is used for slow flight: clean, flaps only, or flaps and gear are all OK.  The FAA commercial pilot ACS (do you use this in the Great White North?) doesn't require any particular configuration for the slow flight task, so it really is the pilot's choice... in theory.  In practice the examiner may have preferences on the check ride, so it behooves to you to talk to him in advance if possible.

That said, the ACS does require the "landing configuration" for power-off stalls and "takeoff configuration" for power-on stalls.  Since both of these require gear down, and since slow flight work is often combined with stall work, I typically fly slow flight with the gear down.  I also tend to set the flaps to the "takeoff" position, since this reduces the required pitch attitude to maintain level flight at low speed.  You can certainly fly slow flight in the clean configuration, but the higher pitch attitude required to do so is less comfortable, and can have a negative impact on cooling.

Thanks Vance, 

Not sure what ACS is...so assuming no, we don't do it.

I agree with your thought on the gear down/flaps TO.  The slow flight/stalls in my opinion are about simulating the departure/landing events so a similar configuration should not be an issue. In a 172 there are not many other options, so that kind of takes care of itself.

 

iain

[Hank]

Why are you doing slow flight at 120 knots? Down here, slow flight was whatever made the stall warning sound, but recently the FAA prefers speeding up just enough to silence the buzzer. Since Mooneys are certified, your stall speed at gross should be less than 61 knots. 

For what it's worth, as I slow around 100mph, I add Takeoff Flaps and continue to slow to the desired speed. For me, 2300 is my typical low altitude, short hop setting, so I use that and reduce throttle until reaching the desired speed.

Good luck practicing, and stay safe!

[Vance Harral]

23 minutes ago, milotron said:

Not sure what ACS is...so assuming no, we don't do it.

ACS = "Airmen Certification Standards" - the document which governs FAA flight tests.  It's an evolution of the old PTS ("Practical Test Standards").  The FAA Commercial Pilot ACS can be found at https://www.faa.gov/training_testing/testing/acs/media/commercial_airplane_acs.pdf.  Presumably Transport Canada has some equivalent, it may contain exactly the same language.  In any case, you should read whatever document governs your flight test and see if it has anything to say about configuration for slow flight.

27 minutes ago, milotron said:

In a 172 there are not many other options, so that kind of takes care of itself.

Yeah, in a 172 the only real choice is where to set the flaps, if any.  Way back in the 1990s when I was doing my private pilot training, the instructor that taught me slow flight wanted flaps fully extended (all the way to 40 degrees in some 172 models!), which in turn required enormous amounts of power to maintain level flight.  Looking back, I don't think that makes much sense.  I demonstrated slow flight in a 172 yesterday to get a CFI checkout at a local flight school, and when I asked the chief pilot where he wanted me to set the flaps for the demonstration, he said he was indifferent about it.

[carusoam]

A few things to keep in mind, from the laws of physics...

1) Slow flight is typical of traffic pattern activities... 90kias or so...

2) 90 is a typical approach speed for IR flight.

3) 90 is usually above Stall speed with low bank angles and flaps at the T/O position...

4) There is a power setting that will maintain 90 and altitude at the same time...

5) You won't be able to cruise to the practice area and set the power setting for slowing down, it will take forever and you will be beyond the practice area quickly.

6) If you want to slow down quickly... remove the power completely while maintaining altitude.  A very dynamic situation... trim, trim, trim.  Adding configuration changes is like adding brakes... gear down, prop in, flaps down, speed brakes, right rudder, and/or crossed controls...

7) As you get to 90, on target altitude, add back the power setting you have for 90. Finish trimming for 90.

8) expect the power setting for 90, and maintaining altitude, is the same power setting you use approaching the traffic pattern.

9) NA planes use a number near 16”.  Throttle fully out is less than 12".  MP for a TC'd plane is pretty similar in the traffic pattern.

10) This activity is very much a multi-tasking activity. The faster you can scan instruments and adsorb the details, the better off you will be.

11) Energy Management 102... you are staying at a defined altitude.  Too much power you go faster...  too little power you go slower

12) The slower you go... more AOA will be needed .

13) More AOA... comes with large helpings of induced drag....

14) More drag... requires higher MP to maintain altitude...

15) Having The Stall horn sounding... requires an AOA increase that is typical of an ASI below 65(?).

16) High AOAs With Power On to maintain altitude generates a fair amount of (? Add word here) tendency to turn left.  

17) defending against the left turn tendency, Use the right rudder to keep the nose point towards a target or keep the ball centered.

18) it always helps to be flying slowly before reaching the practice area.  No need to get there quickly to have to add so many changes to get slowed down, and configured properly.

19) The CPL is a lot about demonstrating all the skills of the plane. Speeding up, slowing down, configuration changes, and multi-tasking along the way.... all while maintaining altitude or Vs or something....

20) Are you familiar with what adding 1” of MP does for your nicely trimmed plane?  Adding an inch of MP usually starts a climb of about 100 fpm (generally). If you are on speed and have an unwanted 100fpm climb going.... remove an inch of Mp.

21) Taking out an inch of MP... does the same thing in reverse. 100fpm descent...

22) If your magic reference MP is 16”, and you are flying the traffic pattern level at 90kias... Abeam the numbers, you pull the throttle back 4”... and Check the VSI... it settles around a 400fpm descent...

23) Slow flight and stalls go together. Be real familiar with Stall speed charts, and effects of bank angle, WnB, and crossed controls...

24) Don't forget all the usual training things like clearing turns and the like... safe altitudes are important for this.

25) That would be the top 24 ideas I would be ready to discuss on the way to flying slowly...

Keep in mind, this is from the memory of a PP.  Not a CFI or CPL.

I'm open to discussion...

Best regards,

-a-

[Vance Harral]

Another technique for slowing down and staying within the confines of a small practice area is to add drag via steep turns.  Cruise to the practice area, reduce power, make clearing turns as necessary, then roll in and put on some "G"s to slow down.

The Commercial ACS standard for steep turns is "approximately" 50 degrees of bank, which is 1.5G of load factor assuming level flight.  Salty old flight instructors will sometimes ask for commercial steep turns at "59 1/2 degrees" of bank, or about 2Gs.  Anything in that range will slow you down pretty well through a 180- or 360-degree turn, and is an excellent demonstration of the drag associated with steep turns.

I add the usual safety disclaimers here: clear for traffic before maneuvering, be mindful of the increase in stall speed with load factor, etc.  But since the Commercial Certificate requires a greater degree of proficiency in steep turns anyway, it's not an unreasonable technique.

[bradp]

Any reason why you can’t be maneuvering in controlled airspace?  I do all the time near my home base.  I personally wouldn’t go 50 nm over some patch of ocean to do anything in a single engine plane. 

[jlunseth]

Well, since you are from Canada you should probably get the Canadian Practical Test Standards or whatever equivalent they have up there, and see what they say.  FWIW I always to slow flight in a landing configuration if for no other reason than to be able to slow the aircraft down.   K’s are heavier than J’s and although I haven’t flown an F, I am pretty sure they are heavier than an F also.  My experience with my K is that when it gets behind the power curve it takes more power than you might expect to keep it in slow flight.  Its been awhile since I did my commercial, so I really don’t remember what the power setting was, just that the plane would fall behind the curve as it slowed, and it was generally necessary to put power back in to hold slow flight.