Newton's laws of motion as applied to me.

General Aviation focused journal, recounting the process of learning to fly and of achieving the private pilots license.

Thursday, August 04, 2005

Lesson 21, Crosswind Circuits

The intention this morning was to carry out another hour of solo circuits, however the weather did not comply. The sky was mostly clear with scattered cloud however the wind picked up, the METAR reported 10knts which didn't feel right standing on the apron with the wind gusting around.

I went up with a different instructor; Mark as Antonio is on holiday, our plan was to check-out the wind in the air and if all was well then I would solo. We took-off and did the first circuit, the wind strength immediately became obvious once in the air and on final to land the tower informed us of 15knt crosswind gusting 20. My first landing was poorish, largely because of the turbulent air. We went around again and Mark mentioned that I was unable to solo in these conditions (there is a 10knt maximum legal restriction on student pilots). Rather than ending the lesson I decided to get in some more crosswind practice, we did another 5 circuits which I was generally pleased with as I got another opportunity to practice different crosswind techniques.

The first technique is the conventional slideslip; the aim is to line up straight with the runway and drop a wing into the wind and apply a sideslip, this requires a little more co-ordination although is easy to maintain a constant descent onto the runway due to the better visual aspect. The problem with the sideslip is in gusty conditions the approach can easily go astray and any strong down gusts towards the lowered wing can cause a steep wing angle in a split second (experienced this) cross controlling at low air speed in gusty conditions is risky. The second technique is the kickout method, for this method the aircraft is crabbed into the wind during the descent on final with the centre of gravity tracking the extended centre-line, the aircraft is kept straight and level and in balance with the rudder. The flare is carried out in this configuration and just prior to touching the ground so the aircraft is flying a couple of inches from the surface with no sink rate you lower the upwind wing to place the wheel onto the runway whilst kicking the downwind rudder to bring the aircraft straight out of the crab, this causes the aircraft to track straight with no drift from the centreline, once established reducing the bank angle places the downwind wheel onto the surface followed by the nose wheel. The kickout technique is basically a side-slip executed right at the point of touch-down.

Having tried both techniques I am now convinced of the kickout method as each landing ended up straight and gentle. I guess each pilot will have his own preference but so far this appears to me mine, although I guess the technique could vary for different aircraft, that I will have to find out in time. I have been lucky to have practiced quite a few crosswind landings at between 15 and 20knts, apparently many student pilots have to often wait for months for the right conditions. I enjoy the challenge of it and hope I will get more opportunities over the coming months.

Other observations to note here; the Katana has a maximum demonstrated crosswind of 15knts, it seems a little low to me as the Katana has very reactive controls, only the slightest of movements on the stick and rudder is needed to bring it out of a dangerous bank angle, on the downside being so light it tends to get blown around a little more than the heavier four seaters (so informed by my instructors).

Anyway fun! I would have liked to have clocked up another hour of solo fight today but the crosswind practice was very worthwhile. It was also mentioned today that I am pretty much done with circuit practice and any further practice I do in the circuit should be at my descretion and only solo, mainly to build self-confidence. I think it is worthwhile for me to solo a few more times in the circuit and no doubt I will get plenty more chances.

5 Comments:

  • At Thursday, August 04, 2005 9:17:00 pm, Blogger Oshawapilot said…

    The maximum "Demonstrated" crosswind component on a C152 is 12 knots, so don't feel bad. :-)

    I've been reminded numerous times that the word "Demonstrated" is important. That states the maximum number that an aircraft manufacturer, during the certification process, felt safe to apply to the aircraft.

    It doesn't mean that it can't be landed beyond those limits, but it's not "demonstrated". So, basically, an aircraft manufacturer covers their rear-ends if someone crashes trying a 90 degree crosswind landing. :-)

    During the airshow here at my airport a while back due to a runway closure (As a result of the overflow fly-in traffic) everybody was landing on runway 30 when the winds were 15G20 at 220.

    If there was ever a better demonstration of safe landings being capable at signifigantly more then the usual "demonstrated" crosswind limits for most planes that were flying into the airport, that was it.

    Those sorts or landings are where a sideslip is a good option, as trying a crab-and-kick would result in one nasty (probably dangerous) crab on approach, and crabbing that seriously would require a *perfect* crab/kick to avoid a nasty sideload at touchdown.

     
  • At Thursday, August 04, 2005 9:58:00 pm, Anonymous Anonymous said…

    I have not been taught to slip at all. In fact I don't think they teach it to commercial students either. I have not idea why but I speculate that the situation that Chris touches on of being crossed up at low airspeed and alititude is a lot more dangerous than side loading the gear, at least in the minds of my instructors.

     
  • At Friday, August 05, 2005 3:05:00 am, Blogger Oshawapilot said…

    Hard to say. It's all we are taught here in Canada, and I don't see any additional accident statistics that could be attributed to it.

    Unless one is dealing with a very heavy crosswind, the amount of sideslip required to align with the runway on approach is usually very little.

    Compared to a forward slip (Which we are taught here for controlled and rapid altitude loss) it's a night and day difference.

     
  • At Friday, August 05, 2005 8:54:00 am, Blogger Chris said…

    Our training is much the same, we get taught primarily the kick-out method, side-slips are taught additional to the syllabus. I don't have enough experience yet to make my own judgements therefore I rely on what I am told; apparently all commercial pilots around the world are taught to use the kick-out method due to the increased safety. Cross-controlling an aircraft deliberately has an inherant problem at low airspeed purely because if the aircraft is inadvertantly stalled, pro-spin forces are already being applied.

    I do see however that I have yet to read a crash report where a side-slip was a direct reason for the crash. So I guess they are good arguments both ways.

    Side-slips to a landing were taught here as the conventional approach up until fairly recently, now the conventional approach has swopped to the kick-out.

    Having practiced both I am happier with the kick-out purely because my landings were better :-).

     
  • At Friday, August 05, 2005 10:10:00 pm, Blogger Oshawapilot said…

    Having never tried a crab/kick crosswind landing, I can't really speak to a preference.

    FWIW, the main reason that crab/kick is generally used in commercial aviation is that forward slips cause passengers to freak out. Picture the first time you experienced a full forward slip as a student, multiply that feeling and attitude by commercial-airliner proportions, and then add 300 people who probably know little to nothing about aviation as a whole. :-)

    It's certainly possible.

    Checkout the following story about the "Gimli Glider" - an Air Canada 767 that ran out of fuel and made an emergency landing. Their use of a forward slip is prominently mentioned, as are the reasons they are usually avoided in commercial aviation.

    http://en.wikipedia.org/wiki/Gimli_Glider

    Just for interests sake. :-)

     

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