Cross-control vs. Slips

Canuk
  • Cross-control vs. Slips Canuk

    In flight training, you're always told not to cross-control, (for example, rolling right aileron, and stepping on the left rudder), but it seems to me that is exactly what a slip is doing.

    Is it that a slip is intentional, and a cross-controlled situation is typically unintentional?

  • You are right: A slip is a cross-controlled (and uncoordinated) situation. It's exactly what your instructor was teaching you to avoid during your early lessons.

    As far as nomenclature goes: all slips are cross-controlled maneuvers, but not all cross-controlled maneuvers are slips: On climb-out in most piston singles you will be stomping on the right rudder to offset the plane's left-turning tendencies, and you will probably notice that you're rolling in a tiny bit of left aileron (which offsets the banking tendency introduced by the rudder) - your controls may be very slightly crossed, but the result is coordinated flight (a centered ball).


    The real difference here between an "unintentionally cross-controlled situation" and an "intentional slip" is the intentional bit: When you are knowingly slipping the aircraft - for example to bleed off altitude on a high final without increasing your airspeed - you're aware that you're flying in an uncoordinated and aerodynamically unstable condition. You're aware of the risks, and are hopefully monitoring the aircraft carefully to avoid a stall/spin.

    For a little more insight, faaflighttest.us has a reprint/copy of an Aviation Safety article from April 2006 which is worth a read, and possibly an hour in the air practicing some of what they discuss with your instructor so you can get the "feel".

Related questions and answers
  • Following acceleration paramters are transmitted from Inertial Reference System (IRS) to Flight Control System (FCS) Flight Path Acceleration Along Track Acceleration Cross Track Acceleration Vertical Acceleration Unbiased Normal Acceleration Along Heading Acceleration Cross Heading Acceleration I only know acceleration based on the aircraft axis i.e lateral, longitudinal & Normal acceleration but what these acceleration paramters signifies?

  • In flight training, you're always told not to cross-control, (for example, rolling right aileron, and stepping on the left rudder), but it seems to me that is exactly what a slip is doing. Is it that a slip is intentional, and a cross-controlled situation is typically unintentional?

  • Does time logged in these foreign-registered aircraft (cross country, etc) count towards US certificates or ratings? Or is it flight experience that should be excluded from an 8710?

  • Provided an aircraft with a fly-by-wire system, there are basically two possible choices when it comes deciding how to let the pilots interface with it: rate control / attitude hold: a deflection of the stick will command a certain rate, releasing it will make the system maintain the current attitude. See the Airbus Normal control law. direct control: a deflection of the yoke will directly translate to a deflection of the surfaces, mimicking the "old" mechanical control setup. It is my understanding that this is the design choice of Boeing in its new aircrafts. I do not wish to discuss

  • This recent comment reports that: the IMU on new (plane) would localize the aircraft to within 3 feet after a cross-country flight, without any GPS input other than the starting location. I somewhat doubt about this statement, at least for an IMU based solely on inertial measurement: over the duration of a flight, I fear much more error accumulates. So what's the precision of a modern Inertial Measurement Unit over say the duration of a flight, and from what sources is that obtained? If some source (in particular, GPS) becomes unavailable, how does it degrade that accuracy?

  • How do flying wings, like the B-2 Stealth bomber, actually keep themselves from yawing out of control without a vertical stabilizer? For the record, I assume this has to be a simple mechanics... WWII. They didn't have flight control computers back then, and the only control complaints I recall them having is that early versions had a tendency to flip over backwards when approaching stall speeds, well, that and the ground effects were pretty strong. But, no mentions of going into flat spins when going into hard maneuvers (that I recall). So how do they control that Y axis on flying wings

  • In a full motion Level C or D simulator like those used by the airlines and for jet type ratings: How should a pilot log the simulator time in their logbook? I.e. Can you log: Total Time Instrument Time Time in Type Cross Country Time Night Time Landings (including night landings) Dual given/received Anything else?

  • Autopilots used in piston GA usually do not have throttle control. They only manage the control surfaces. However to trim an aircraft one needs to play on both throttle setting (and more physically, thrust) and control surface deflections (aerodynamic forces). What happens if the autopilot cannot trim the aircraft due to the propulsion settings? Is there any alert from the autopilot for the pilot?

  • to switch to ground frequency with this clearance (assume I just landed)? N12345, right on E, cross 27 R, contact ground .9 Should I call ground (or switch frequency, so I no longer hear the tower) before or after crossing 27 R? My by-the-book assumption would be immediately, as there's no "then" or "after crossing" or similar, but somehow that feels wrong. I suppose normally it doesn't really matter, but in the case of someone (which includes me, everyone makes mistakes) doing something wrong, where would they call me as I'm about to cross 27 R? The reason I ask is that I saw exactly

  • An aircraft's Aircraft Communications Addressing and Reporting System uses line of sight HF via ground stations or satellites to communicate with its base station. This system allows for three types of messages to be sent: Air Traffic Control Aeronautical Operational Control Airline Administrative Control Aeronautical operational control and airline administrative control messages are used to communicate between the aircraft and its base. Various types of messages are possible, for example, relating to fuel consumption, engine performance data, aircraft position, in addition to free

Data information