Landing speeds for C172, 75/70/65?

Discussion in 'Pilot Training' started by James Darren, Dec 28, 2013.

  1. James Darren

    James Darren Pre-Flight

    Joined:
    Jul 5, 2013
    Messages:
    81
    Location:
    Los Angeles, CA
    Display Name:

    Display name:
    James Darren
    Hi,

    I've been soloing for a couple weeks now & my CFI has taught me that the landing speeds for a C172 is 75kts on downwind, 70kts on base & 65kts on final.

    It seems most information I'm finding online has the speeds as 85kts on downwind, 75kts on base & 65kts on final.

    Has anyone else been taught the 75/70/65kt speeds that I have been told?...
     
  2. Henning

    Henning Ejection Handle Pulled

    Joined:
    Feb 26, 2005
    Messages:
    39,481
    Location:
    Ft Lauderdale FL
    Display Name:

    Display name:
    iHenning
    65 at the top of final at max gross weight. Landing speed of a 172 is about 43kts, less when light. If you are doing 65 over the numbers trying to land solo, I bet you are having a heck of a time landing.
     
  3. FastEddieB

    FastEddieB Final Approach

    Joined:
    Oct 14, 2013
    Messages:
    9,841
    Location:
    Lenoir City, TN/Mineral Bluff, GA
    Display Name:

    Display name:
    Fast Eddie B
    To be accurate, define "landing speed".

    Many arguments are had only because people are using the term to mean different things.

    I equate it with touchdown speed. In that case, conditions permitting, I would try to be "at approximately stall speed"' which is slower than any of the figures you gave.

    (And which iHenning beat me by two minutes in pointing out!)

    As approach speeds go, does the POH address that? In any case your latter figures look pretty close to me.

    And they should also be pretty close to 1.3 times the stall speed in each configuration (or possibly 1.2 for a short field).
     
  4. Henning

    Henning Ejection Handle Pulled

    Joined:
    Feb 26, 2005
    Messages:
    39,481
    Location:
    Ft Lauderdale FL
    Display Name:

    Display name:
    iHenning
    1.3 Vso is 55kts in a 172, and that's at gross weight. A 172 shouldn't be crossing the fence above that.
     
  5. James Darren

    James Darren Pre-Flight

    Joined:
    Jul 5, 2013
    Messages:
    81
    Location:
    Los Angeles, CA
    Display Name:

    Display name:
    James Darren
    I guess I should say I meant the pattern speed for downwind, base & final.

    And I meant 65kts at the top of the final...
     
  6. Henning

    Henning Ejection Handle Pulled

    Joined:
    Feb 26, 2005
    Messages:
    39,481
    Location:
    Ft Lauderdale FL
    Display Name:

    Display name:
    iHenning
    65 at the top of final is fine because it keeps you nearest your best glide speed, once you get below that you're 'on the backside of the power curve' and it will require more energy to keep on a glide path for the runway. If you are on a short steep path already and the numbers are moving down in your windscreen with the throttle closed, you can slow down early to increase your sink rate.
     
  7. flyingron

    flyingron Touchdown! Greaser! PoA Supporter

    Joined:
    Jul 31, 2007
    Messages:
    19,381
    Location:
    Catawba, NC
    Display Name:

    Display name:
    FlyingRon
    1.3 Vso applies to calibrated airspeed. Note that the 172 has a lot of divergence between indicated and calibrated down at Vso.
     
  8. jonnyjetprop

    jonnyjetprop Cleared for Takeoff

    Joined:
    Jul 21, 2011
    Messages:
    1,042
    Location:
    Apopka, FL
    Display Name:

    Display name:
    John
    Those speeds are fine. Keep doing what your instructor told you to do. Understand that he's trying to keep your sight picture consistent. This will help you keep your pattern and approach looking the same. As you gain experience, you can vary the numbers except what the plane touches down at. That's why you see numbers all over the place. FWIW, I just flew a rental 172 at 120 kts in the pattern. Why? I was at a busy class C airport and I was following a turboprop to the runway. I also have more experience, and I felt comfortable doing it. I still touched down around 50ish (if you're looking at the airspeed in the flair, that's a problem).



     
    Last edited: Dec 28, 2013
  9. alfadog

    alfadog Final Approach

    Joined:
    May 3, 2010
    Messages:
    5,061
    Location:
    Miami
    Display Name:

    Display name:
    alfadog
    You might as well move a bit quicker in the downwind if you do not need the time. I use 90/80/70 MPH.
     
  10. White Bird

    White Bird Pre-Flight

    Joined:
    Mar 6, 2013
    Messages:
    99
    Display Name:

    Display name:
    White Bird
    Yes, this is how I have been taught 75/70/65 and 60 above the numbers
     
  11. SoloEqs

    SoloEqs Line Up and Wait

    Joined:
    Aug 9, 2013
    Messages:
    786
    Location:
    From out of the clear blue of the Western sky
    Display Name:

    Display name:
    K W
    Fly no faster than the airspeeds that work with the CFI aboard, and no slower than 1/3 of the difference between that airspeed and stall -- that is, if your stall speed were 50 IAS, and you are at 65 over the fence with the CFI aboard, you want to be between 60 and 65 over the fence when solo.

    Don't worry that you're a little long on your solo, your instructor knows that you're used to the way the bird performs with the extra "sandbag" in the right seat. You're probably going to see another runway stripe go by before touchdown -- the only thing that counts is HOW you touch down, and how well you're lined up on the runway.

    Also, if you think you're getting into trouble, ABORT THE LANDING. Get some air between you and the ground, and try again. The only time I ever saw anyone wreck a plane on his first solo was a local police chief who let his pride keep him on a bad approach. Then he gets out his pocket phone and calls in a motor vehicle accident, because he knew that everyone knew that he was flying and he didn't want the world to know that he had screwed up. I don't think he kept flying after that.
     
  12. frfly172

    frfly172 Touchdown! Greaser!

    Joined:
    Oct 22, 2008
    Messages:
    14,546
    Location:
    mass fla
    Display Name:

    Display name:
    ron keating
    Why does everyone come to the forum to challenge their instructor. After you pass the test,then experiment with the best speeds for you.
     
  13. Henning

    Henning Ejection Handle Pulled

    Joined:
    Feb 26, 2005
    Messages:
    39,481
    Location:
    Ft Lauderdale FL
    Display Name:

    Display name:
    iHenning
    Because excess speed is the primary impediment to learning how to land.
     
  14. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    Depends on the 172. What you use in a 172S with 30 flaps at full 2550 MGW is significantly different than what you'd use in a 172A with two aboard, half fuel, and 40 flaps. As noted above, the best thing to do is run the numbers to determine Vs0 CAS at your actual gross weight, multiply that by 1.3, and then convert that from CAS to IAS. Vs0 determination starts with the stall speed table of your owner's manual/POH (e.g., C172P at MGW with full 30 flaps is 46 KCAS). If you're less than MGW, convert that MGW stall speed to actual weight stall speed using the square root relationship:

    Vs(actual) =Vs(MGW) * sqrt(actual/MGW).

    If that C172P is at 2100 lb, then sqrt(2100/2400) is .94, so stall speed at landing weight is 43 knots CAS, and 1.3 Vs0 is 56 knots. Now, you have to convert 56 KCAS to indicated airspeed, so it's back to the manual where you see it's 54 KIAS, and that should be your target airspeed on final.

    You can add some speed to that in gusty conditions. The usual recommendation is to add half the gust factor, which is the difference between steady state and peak gust values. So, if they're calling the wind 16G24, the GF is 8, half the GF is 4, and your target airspeed is now 54+4=58 KIAS.
     
    Last edited: Dec 28, 2013
  15. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    On downwind, I find you want rather a faster speed than you'd need on final. I usually recommend about 1.5 Vs1 (i.e., clean). Likewise, on base, I'm aiming for about halfway between downwind and final speeds. In my C172P example above, clean stall at 2100 lb would be about 49 KCAS, so I'd be targeting about 73 KCAS or 72 KIAS. On base leg with half flaps, I'd be aiming for about 63 KIAS, and then the abovementioned 54 KIAS on final.

    BTW, for pretty much all light planes, rather than trying to compute all this every landing, if you run and memorize the numbers for MGW (there's only three to learn -- downwind, base, and final) and then drop 1 knot for each 100 lb below MGW, you'll be close enough.
     
  16. tehmightypirate

    tehmightypirate Line Up and Wait

    Joined:
    Nov 1, 2013
    Messages:
    632
    Location:
    Maine
    Display Name:

    Display name:
    TehMightyPirate
    This! Ask your instructor (or yourself) why you use any set speed in the pattern. It's all about stability (there's probably a better term for it somewhere) and efficiency.

    [​IMG]

    (Ignore the airspeed numbers, for a Cessna 172 Vmd, or min. drag, is around 75 knots) Near the bottom of the power curve is the maximum lift to drag speed, it's also the stablest. At this point on the power curve the plane will naturally try to recover a set airspeed if you change the pitch. Makes a great pattern speed. A bit above this speed is the speed I think makes the most sense for a long, straight in approach (instrument approach) as it's stable, efficient, within the region of positive command, and not too far from our short-final speed that we can't dump in some flaps and get down to our target landing speed with any real difficulty.

    However, it's too fast to land at (by far). Lower than this speed you're in a region of negative command and you're dragging the plane in to landing (think slow flight, or a high headwind landing). So, what you need is an approach that gradually slows down from the stablest speed in the pattern to your target landing speed while minimizing your time in the region of negative command. A higher airspeed at the start of the pattern also gives you more airspeed for emergencies, keeps you near to best glide so that you're almost trimmed and set for an engine-out, and gives a larger margin of error against stalls.

    Thus, 85/75/65 is my target speeds in downwind, base, and final. I usually use minimal power adjustments and hit these speeds almost entirely with flap extensions in the 172. I've heard of 75/70/65 as it's a more stable attitude with less adjustments, and closer to Vmd, but it requires too much fiddling with power for my taste and I like the higher speed for safety and efficiency in the pattern.

    Other things to keep in mind are headwinds and crosswinds. A rule of thumb I use is if I have a crosswind or headwind greater than about 10 knots then I use 20 degrees of flaps only (runway length permitting) and add half the headwind or crosswind (whichever is greater) to my final airspeed.

    Lastly, on short-final I will usually be down to about 60 knots, then over the numbers I should have been power off and slowing to my final touchdown speed.
     
  17. denverpilot

    denverpilot Tied Down PoA Supporter

    Joined:
    Nov 8, 2009
    Messages:
    54,015
    Location:
    Denver, CO
    Display Name:

    Display name:
    DenverPilot
    I think others have covered it but to reiterate in words meant for a budding pilot...

    Your instructor has taught you a rule of thumb that's safe for that aircraft.

    As you mature as a pilot you'll realize there's more going on and learn to rely on the POH, a little simple math, and your butt feel for the characteristics of the individual airplane.

    I was taught 85/75/65 for a 182. Later when struggling with floated landings I pulled out the POH and learned it was way too fast. When I bought a share of a 182 with a STOL kit it was straight to the POH and it was WAY too fast.

    The problem is the Law of Primacy. I *still* think "85" in my head on downwind and then have to mentally adjust for what I know to be true. So don't hammer the numbers too hard into your head. Learn to fly your specific airplane. It'll serve you better as you switch types.

    No rush to that stage. Keep working on learning the airplane's feel at all speeds.
     
  18. Paul Hamilton

    Paul Hamilton Pre-takeoff checklist

    Joined:
    Jul 4, 2013
    Messages:
    162
    Display Name:

    Display name:
    Paul H
    If it's a 172M, the POH calls for an approach speed between 55 and 65 knots. Your instructor is having you fly at the top of that range, which seems like a safe choice.
     
  19. Henning

    Henning Ejection Handle Pulled

    Joined:
    Feb 26, 2005
    Messages:
    39,481
    Location:
    Ft Lauderdale FL
    Display Name:

    Display name:
    iHenning
    It's actually the less safe choice especially when the book numbers are for max gross weight and already high for the training environment. The safest choice, and easiest to execute, for a landing is always the lowest state of energy.
     
  20. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    Y'all be careful with these numbers when they come from older POH's. Before 1977, most light single POH's were entirely in mph. After that date, they went all knots. So, in older 172's with mph airspeed indicators, 65 is about right, but it's a bit fast in a 1980's 172 with knots primary.
     
  21. sdflyer

    sdflyer Pre-takeoff checklist

    Joined:
    Aug 20, 2007
    Messages:
    434
    Location:
    SoCal
    Display Name:

    Display name:
    sdflyer
    I fly 90 on downwind, 80-75 on base, 65 on final, and 60 over trashhold.
     
  22. alfadog

    alfadog Final Approach

    Joined:
    May 3, 2010
    Messages:
    5,061
    Location:
    Miami
    Display Name:

    Display name:
    alfadog
    Knots?
     
  23. marcoseddi

    marcoseddi Cleared for Takeoff

    Joined:
    Sep 29, 2012
    Messages:
    1,374
    Location:
    Long Branch NJ
    Display Name:

    Display name:
    marc
    It's a great thing, this is flying I think its a great to question everything possible you will learn more and make sure you hear it all!
     
  24. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,133
    Display Name:

    Display name:
    Tom-D
    Trick is,, knowing the real stall speed of these old, often bent aircraft.
     
  25. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    I've never had any problem determining that. And if they're bent enough that stall speed is changed significantly, they really aren't airworthy.
     
  26. Henning

    Henning Ejection Handle Pulled

    Joined:
    Feb 26, 2005
    Messages:
    39,481
    Location:
    Ft Lauderdale FL
    Display Name:

    Display name:
    iHenning
    That's why I tell people to go up and stall the plane and find the real numbers, especially the solo half fuel number, and go in the IAS-CAS table and come out with their 1.2 & 1.3 Vso numbers.
     
  27. sdflyer

    sdflyer Pre-takeoff checklist

    Joined:
    Aug 20, 2007
    Messages:
    434
    Location:
    SoCal
    Display Name:

    Display name:
    sdflyer

    Yes knots
     
  28. ateamer

    ateamer Line Up and Wait

    Joined:
    Dec 19, 2007
    Messages:
    777
    Location:
    Port St. Lucie, FL
    Display Name:

    Display name:
    ateamer
    Why the suggestion to use only 20 degrees of flaps and higher airspeed in a crosswind? A 172 can be landed - no problem - in a 15 knot direct crosswind with full flaps without adding airspeed, assuming a steady wind with no gusts.
     
  29. Pilawt

    Pilawt Final Approach

    Joined:
    Sep 19, 2005
    Messages:
    8,109
    Display Name:

    Display name:
    Pilawt
    Every C-172 factory owners manual and POH ever printed, from 1956 to present, has contained language to the effect of, "Normal landing approaches can be made with power on or power off with any flap setting within the flap airspeed limits," and, "When landing in a strong crosswind, use the minimum flap setting required for the field length." These particular quotes are cut-and-pasted from the 2010 C-172S POH.

    The difference in stall speed (and therefore minimum touchdown speed) in a 172 is only a couple of knots at 20° vice 40°, for those models that allow 40° flap deflection; and obviously even less difference between 20° and 30° (full flap in 172P and later).

    The late Bill Thompson, in his book chronicling the development of the Cessna single-engine line, wrote in the chapter devoted to the 172, "... [W]ing-low drift correction in crosswind landings is normally performed with a minimum flap setting (for better rudder control) ..." [emphasis in original].

    Thompson was an engineering test pilot for Cessna for 28 years, and was Cessna's Manager of Flight Test & Aerodynamics. He served as the GA representative on NASA's Aerodynamics/Aeronautics Committees, and was an FAA Engineering Representative for flight test pilot/analyst assignments. He had the qualifications to back up what he wrote.

    Some pilots disagree with Thompson, Cessna, and the POH about flap settings in crosswinds. A lively discussion usually ensues when this topic is raised here. But your question was "why the suggestion," and that's the answer.
     
    Last edited: Dec 29, 2013
  30. danamerfly

    danamerfly Filing Flight Plan

    Joined:
    Apr 9, 2012
    Messages:
    18
    Location:
    Jacksonville, FL
    Display Name:

    Display name:
    Meredith Holladay
    This is the best response I've seen to this whole thread. One of the lessons Dana and I try to teach our students early on is to "not be a robot." You can (and will) safely fly a Cessna 172 (or most any single engine training aircraft) in the traffic pattern at just about any speed within its operating envelope, both with and without flaps deployed. Most of the time, your 85/75/65 or 80/70/60 or whatever will work just fine.

    But sometimes it won't. Here are just a few examples:

    - If other aircraft are flying excessively wide/long traffic patterns at your non-towered airport, don't be a lemming and follow them halfway into the next county. If the person in front of you decides to turn a 2-mile base, you can slow down on the downwind to minimize the distance you travel away from the airport while maintaining safe separation from the other aircraft. This can also be useful at a busy towered airport where the controller may intentionally stretch out the downwind to accommodate faster aircraft departing or arriving on a straight-in final. You should feel comfortable slowing down on the downwind without losing altitude. There is nothing wrong or unsafe about flying downwind at 70 with 10 or 20 degrees of flaps. This is not "slow flight" just "slower flight."

    - The wind is strong and gusty. 65 on final with full flaps may feel comfortable in calm or light winds, but it may feel uncomfortable on a windy day. Try 65 or 70 knots and 10 or 20 degrees of flaps on final.

    Hopefully your instructor has taught / is teaching you to fly the pattern at various speeds and configurations so that you can develop judgement on what works best in various situations.

    Hope that helps.
     
  31. James Darren

    James Darren Pre-Flight

    Joined:
    Jul 5, 2013
    Messages:
    81
    Location:
    Los Angeles, CA
    Display Name:

    Display name:
    James Darren
    Thanks to all for your replies.

    I have total respect for my instructor & am not challenging his training, more curious as to how others are being taught, and the possible reasons for the different speeds.

    The speeds have worked quite well for me most of the time. I'm flying a 172SP and from an airport in SoCal where we get very little wind, usually 5-10kts max. My limitation for solo flying is a 5kt crosswind so I haven't really needed to change the speeds much so far.
     
  32. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    Yes, they can. But that doesn't mean they should. And the FAA has lots of good reasons why they recommend using full flaps as your normal landing technique. One of the biggest problems I see as an instructor is pilots trying to do it differently every time -- different speeds, different configurations. If you're flying 500 hours a year and landing in all sorts of different conditions, you get enough repetitions that you can have several different landing configurations and be good at all of them. If you're flying 50-75 hours a year, none of which involve serious pattern practice, my experience says you don't. As a result, I agree with the FAA that doing it the same way every time is your best bet to maintain landing proficiency, and full flaps gives you the best shot at making good landings -- on speed and on target (centerline and touchdown point).
     
  33. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,133
    Display Name:

    Display name:
    Tom-D
    Oh but they are, because they are in a properly altered condition.
     
  34. poadeleted20

    poadeleted20 Deleted

    Joined:
    Apr 8, 2005
    Messages:
    31,266
    Now just how do you figure that? Is there some sort of field approval signed by the FAA detailing the bending of that plane? I've certainly never seen such.
     
  35. Tom-D

    Tom-D Taxi to Parking

    Joined:
    Feb 23, 2005
    Messages:
    34,133
    Display Name:

    Display name:
    Tom-D
    Ever see an STC that changed the empty weight of the aircraft, but did not change the Flight manual/POH/owners manual?

    Ever see a engine up grade that changed the CG yet did not change the aircraft pubs?

    Properly altered aircraft do not need to be bent, but the aircraft can be bent and re-rigged to meet the flight parameters IAW the repair manuals and they will stall differently

    That is why we have + and - throws on all flight controls given in the TCDS.
     
  36. SoloEqs

    SoloEqs Line Up and Wait

    Joined:
    Aug 9, 2013
    Messages:
    786
    Location:
    From out of the clear blue of the Western sky
    Display Name:

    Display name:
    K W
    Because some instructors are idiots, and ALL are human and can make mistakes.

    If your IP says something that doesn't ring right, QUESTION it, because there's something that you either need to learn or that he needs to correct, and if you don't get it right, you can be seriously snakebit.
     
  37. SoloEqs

    SoloEqs Line Up and Wait

    Joined:
    Aug 9, 2013
    Messages:
    786
    Location:
    From out of the clear blue of the Western sky
    Display Name:

    Display name:
    K W
    You're also assuming a pilot who is familiar with the feel of that particular aircraft in crosswinds.

    For a guy in his first solos, it's better to err on the side of caution than to risk discovering why you should have.
     
  38. dmspilot

    dmspilot En-Route

    Joined:
    Oct 20, 2006
    Messages:
    4,142
    Display Name:

    Display name:
    Display name:
    It sure can. At some airports, crosswinds regularly exceed 15 knots.