I believe this is manfacurers candy coating. The difference is that with ailerons you have one wing creating more lift and the other creating less lift causing thus not losing any total lift as ailerons are applied. The same control input on a spoiler equiped airplane causes one spoiler to raise on the wing you want to roll to and nothing happens on the other wing. Therefore you are decreasing lift on one wing and it is not replaced by lift on the other causing a net loss of lift.
Like I said, you have to be cautious of the manufacturers word, but this bit from the web site is from an independant consultant
Gregory A. Feith
International Aviation Safety Consultant
Myth: Flight Spoilers â€śdestroyâ€ť the lift on the wing:
â€śDestroyâ€ť is not a word in the aerodynamic lexicon and unfortunately it is used most often to create an
emotional response. Flight Spoilers, when deployed only reduce the lift-efficiency of the wing in which
the spoiler is deployed. The deployment of the flight spoiler to intentionally induce a roll (typical of a
turn) is similar to and results in the same effect as raising the trailing edge of an aileron. Flight spoilers
are used as the primary flight control for roll in numerous air transport category airplanes, military
airplanes and some general aviation airplanes.
Myth: Flight Spoilers are not as effective as ailerons at slow speeds, because larger control yoke
movements are required for the MU-2B in turbulence during approaches:
This myth has been disproved in numerous flight tests that compared the roll authority of ailerons and
flight spoilers. Roll rates at cruise speeds for the King Air 200 and the MU-2B-60 were found to be
approximately equal when the flight control was exercised to their respective maximum control position.
At approach airspeeds with full roll control authority exercised, the MU-2B continued to achieve greater
roll rates than the King Air 200. The genesis of this myth likely stems from the fact that flight spoilers
are most effective when they are at their maximum deflection. And though there is a nominal change in
roll rate during the initial application of the flight spoiler, the rate progressively increases as the flight
spoiler is deployed until it achieves its maximum rate at maximum deployment. Conversely, the roll rates
in an airplane equipped with ailerons will be the greatest at the initiation of aileron deflection and
progressively decrease with increased aileron deflection. Therefore, although the pilot may be required to
manipulate the control yoke slightly more (than in an aileron-equipped airplane) to initiate a roll action in
the MU-2B, the roll authority will progressively increase proportionally to the increase in control yoke
displacement in the direction of the desired turn.
Myth: Flight Spoiler deflection causes a loss of altitude due to a lateral rotation about the opposite tip
The origin of this myth is based on the perception that in the MU-2B, when the flight spoiler is deployed
to induce a roll (typically a turn) the ascending wing (moving upward) does not increase lift in the turn
but rather the descending (downward moving) wing loses lift and the rotation occurs around the outboard
portion of the wing rather than the lateral axis of the airplane. An aileron equipped airplane, by contrast,
increases lift on one wing while decreasing it on the other. Thus, it is mistakenly believed that the aileron
equipped airplane rotates around the lateral axis that runs through the center-of gravity (CG) i.e., through
the middle of the fuselage, and that the MU-2B, which is believed to have only a loss of lift on one wing,
thus the airplane rotates around the opposite wingtip. This premise is fundamentally flawed and not
supported by the basic aerodynamic principles (or the current laws of physics) that state that the lateral
axis of the airplane transits from nose to tail through the middle of the fuselage, and always intersects the
I'm not sure where you got your data on the MU-2 having a better safety record than other turboprops of its class. I also don't know what makes you think that MU-2 pilots would have less experience than pilots of other simular airplanes either.
I meant to say that pilots of MU 2 and similar aircraft tend to have less experience, not pilots of MU 2's have less than pilots of similar aircraft. Another cut from the web site, sourced from FAA stats
Twelve Year Totals
Accidents Fatal Accidents Fatalities
Cessna 400 Series 255 90 282
King Air 90/100/200/300 169 64 236
Piper PA31-42 Series 159 55 168
Cessna 208 Caravan 128 40 163
Commander 500-600 86 34 92
Swearingen SA-226, 227 60 15 53
Mitsubishi MU2 Series 33 21 38
The single most common factor in recent MU2 accidents has been the absence of formal MU2 training, either that simulator training sponsored by Mitsubishi at SimCom or in-aircraft training provided by Howell Enterprises or Professional Flight Training, in the accident pilotâ€™s operation. This may be in conjunction with such pilotâ€™s operation lacking insurance or the decision by an underwriter insuring a fleet of cargo-only MU2s not to require such training. Joint efforts towards the issuance of the MU-2 Training SFAR in 2008 are meant to address this issue.
-It is also noteworthy that cargo-only operations (including, of course, those with MU2s) are held to a lesser standard of safety-oriented equipment, including not requiring autopilots or ground-proximity warning equipment, by the FAA than are aircraft carrying passengers or a certain number of passengers.
I guess these are raw totals not factored per flight hour or sector, check the web site for further info. You may be able to make more sense of it than me.
This may have been true origonally, however due to the accident rate of this airplane the pilots are required more training to fly the MU-2 than other simular airplanes.
In fact MU-2 pilots are required by the FAA to receive type specific training (simular to a type rating) that is very unusual for aiplanes weighing less than 12,500 lbs. The FAA also requires this plane to have an operating autopilot to fly single pilot, another oddity. These requirements are due to the airplane being much less forgiving that most other
Or the MU 2 is sufficiently different from similar types that specific training is advisable. I don't fly in the FAA environment so I can't really comment on this aspect. I've never flown any aircraft without a type rating specific to the type.
The primary effect of engine failure is yaw, and therefore the correct control input is rudder not aileron (or roll spoiler). In fact once the correct rudder input has been made most aircraft require very little or no aileron input.
This is a little misleading. When an engine fails you not only get a yawing moment, but you also get a rolling moment. You are absolutely correct that the correct control imput should be rudder in this airplane. In most any other twin engine plane you can step on the rudder and keep it mostly steady and control the roll with ailerons. This is what kills MU-2 pilots and this is why the additional training is required.
Yep there is a rolling moment as well but my point was that, given correct use of the rudder, it is small and manageable with ailerons or roll spoilers. At least that's what Mitsubishi and the FAA say
Myth: Flight Spoilers cause loss of lift as compared to ailerons:
Obviously, flight spoiler deployment, similar to raised aileron, does reduce the lift efficiency of the wing
and increase drag proportionally to amount of deployment. However, the drag increase from spoiler
deployment is relatively negligible compared to the drag which results from incorrect rudder inputs
(causing a skidding of the airplane) during an OEI (one engine inoperative) event. This was clearly
captured on video during a demonstration flight (shown during the PROP seminars) that revealed that the
proper and timely application of the rudder during the OEI event improves climb performance
dramatically and causes a marked decrease in the flight spoiler deployment required to maintain attitude.
In fact, nearly all of the climb improvement and drag reduction after an engine failure is realized with the
appropriate rudder input. This is true of any non-centerline thrust, multi-engine airplane, whether it is
equipped with ailerons or flight spoilers. In the MU-2B, after the appropriate rudder input has been
established and the appropriate aileron trim (used on the MU-2B to reduce the aerodynamic loads on the
flight spoilers that are felt by the pilot in the control yoke) has been applied to relieve the aerodynamic
forces on the flight spoilers during the OEI, an additional, but small improvement in climb performance
will be evident. This is due to the fact that the performance (drag) penalty is negated as compared to an
aileron-equipped airplane because the flight spoiler is trimmed to a recessed or faired position.
I guess I'm playing devil's advocate here a bit, I have no idea if the MU 2 is a safe plane or not, I've never flown one. Interesting thread though, even though we might be starting to drift a bit. (Yeah right, it's not like I caused the drift by bringing up helicopters)
Sorry for the long post