What is the best way to perform a slow flight manuever?
This question came from Josh:
I have flown with two different instructors, and both demonstrate and teach slow flight in different ways. What is the proper way to do this that is in the private pilot PTS and is what the DPE will look for?
Thanks Josh for your question. Yes, many instructors will have different techniques for the same maneuver. This can be very frustrating for students. In fact, your DPE may even have his own preferred way of performing this maneuver. Here’s the good news: as long as your perform the maneuver to the PTS standards during your checkride, you should be ok.
So what does the PTS (practical test standards) say about slow flight?
First of all, I would recommend buying a copy of the Private Pilot Practical Test Standards so you can read it for yourself. I’d also recommend keeping this with you in your flight kit during your entire training, review it often. You can also download a copy from the FAA website. The PTS states that the objective of the manuever is to determine that you:
- Exhibit knowledge of the elements related to maneuvering during slow flight. (you understand the aerodynamics of the maneuver)
- Select an entry altitude that will allow the task to be completed no lower than 1,500 feet (460 meters) AGL.
- Establish and maintain an airspeed at which any further increase in angle of attack, increase in load factor, or reduction in power, would result in an immediate stall.
- Accomplish coordinated straight-and-level flight, turns, climbs, and descents with landing
gear and flap configurations specified by the examiner. - Divide attention between airplane control and orientation.
- Maintain the specified altitude,+/-100 feet (30 meters); specified heading,+/-10° ; airspeed,+10/-0 knots; and specified angle of bank,+/-10°.
In other words, you should be able to maintain a attitude (and associated airspeed) that if you pitched up (or got any slower) you would almost immediately start to feel the effects of a stall. The examiner is looking to see if you can safely control the airplane at the lower end of the performance sprectrum.
Here is the method that I teach my students, but please don’t take this as the last word. You should always work closely with your instructor for their methods for your particular aircraft and always consult your POH. Here is what I teach when flying an older Cessna 172 with a carburettor.
- Select altitude that will allow recovery no lower than 1500 feet AGL
- Clear Area (two 90 deg. clearing turns)
- Carb Heat On
- Reduce Power to 1500 RPM
- If instructed, extend flaps when below flap operating speed
- As airspeed decreases, adjust pitch to maintain altitude. When airspeed approaches 60 KIAS, gradually increase power between 1800-2100 RPM to maintain altitude. The RPM depends on many things including
configuration and altitude. - Once you’ve stablized at the recommended speed (57 or 60 KIAS) keep the pitch stabilized and make
small changes in power as necessary to hold your altitude. - To recover, smoothly apply full power and adjust your pitch to maintain altitude as airspeed increases.
I hope that this helps some. The key is to work with your instructor (whichever one you pick) and make sure that his / her method conforms to the PTS so you won’t have a problem with your checkride.
Good luck and be sure to let us know how it goes and as always…
Fly Safe!
Brian on Sep 08, 2010
Have you ever entered slow flight without ever referencing an instrument? Knowing you’d be perfectly on heading and +/- 20 feet in altitude every time all day because you can feel your butt and see the horizon. I never entered slow flight like this either, even in years of college flight training nobody ever showed me how easy entry could be and entry is where I always screwed up.
What Paul mentioned here is exactly how I’ve always done it, until recently.
To do this you need to know three visual truths:
1) If you fly at the same point in the distance, your heading will remain unchanged.
2) If you keep the horizon looking comfortable to you (eye level, like you see at the beach and have seen your whole life) then you will be in level flight.
3) The 1G feeling you’ve also felt your entire life, if you keep that 1G feeling in your seat you will be in level flight.
So between a combination of pressure senses in your butt and visual cues from the horizon we can determine level flight. Now go out and enter slow flight by finding a point in the distance to fly to, that is your heading. Next step is reduce the power to idle and begin configuring for slow flight while keeping the horizon eye level and your butt feeling one G. When the yoke can no longer keep 1G on your butt it is time to start bringing in the power till you feel 1G again and begin your full scan to remain in slow flight. If you have 10+ hours you can master this in 20 minutes. Enjoy.
Notice: The horizon eye level is still true in slow flight. For proof, the next time you’re in slow flight sit back and comfortably stare (while the other person is flying if you are dual pilot) at what looks like eye level. You’ll find it is some location on the instrument panel and to your surprise, if you connect the horizon lines from either side of the aircraft, the horizon line passes right through where eye level is.