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(after all, in a
simulator, if the math adds up, the virtual aircraft recovers). As an
experienced simulator instructor, I often have seen pilots perform
recoveries from simulated jet upsets using the methods that have been
taught them in previous simulation sessions, yet which are placing G
loads on the “simulated aircraft” well in excess of actual
airframe or physiological limitations. Many pilots have been pulling
8 to 10 “simulated G’s” in simulators without even
knowing that their performance would not even be close to being
replicable in a real aircraft. When confronted with an actual jet
upset event, these pilots find that their simulator based training
has not prepared them for the real thing, and the results are
predictable. A perfect example of the result of earning the “beat
the sim” using techniques that simply don’t work in
airplanes was possibly demonstrated by the crew of an Airbus that
suffered structural failure after encountering wake turbulence on
departure from a preceding heavy jet. In the recovery attempt that
was made, the immediate speculation among knowledgeable engineers and
test pilots was that the crew used brutal rudder applications that
overstressed the vertical stabilizer, resulting in a structural
failure that resulted in the loss of the aircraft and its 265
occupants. This theory has recently been published as a factual
finding by the National Transportation and Safety Board, which has
directly linked inadequate and improper training to the mishap.
Bottom line: The method the pilots were taught might have worked in
the simulator, but it didn’t work in the aircraft.
Another area in
which modern jet-upset training has been negligent is in the subject
of the difference between recoveries from wake vortex upsets at high
altitude, where very gentle recovery techniques can be used, as
opposed to those encountered close to the ground, where not only is
the potential for impact with terrain a factor but also an envelope
of operation in which the aircraft is likely to be configured in a
high-drag, low roll-rate potential condition. Most pilots do not
understand that the correct recovery from this condition, even if
nose low and descending, requires an IMMEDIATE INCREASE IN THRUST to
overcome the additional drag that will soon result from adding G
loads to the aircraft, followed by a MAXIMUM RATE ROLL to place the
lift vector in opposition to gravity, followed by INCREASING G LOADS
to those which respect both accelerated stall speeds, airframe
structural limits, and human G-load tolerance. This is the subject of
understanding “Cornering Velocity”, which is the velocity
which results in obtaining the absolute minimum radius of pullout. If
you cannot describe Cornering Velocity, and then apply it to recover
from a near-inverted condition at the outer marker with your gear
down and your flaps in approach configuration, you need to come back
to school! If you have been taught to use rudders to influence roll
rate, and have not been thrown against the side of the cockpit by the
resulting lateral G loads, you need to feel it! If you have done a
“superb” conventional unusual attitude recovery to the
satisfaction of your simulator instructor, but have pulled 12 G’s
without knowing it (and have not been corrected by your simulator
instructor), you have been taught to “play a video game”,
but have not received quality training. Don’t fret: There is a
solution: Real Aircraft Training.
At this point it
is hoped that the reader understands that although simulators have
excellent uses in routine flight training and evaluation, they have
definite limitations when an attempt is made to use them outside of
their capabilities. G-loads, rolling recoveries, maximum rate roll
performance, power increases required to respond to high induced drag
conditions due to G loads in low-altitude recoveries, the use of
sideslip angle to increase roll rate, and many other topics should be
a part of the trained professional aviators toolkit. These skills an
only be learned by flying an airplane that replicates the actual
flight conditions that may be encountered in line-operations.
So, this brings us
to the questions of “What type of aircraft should be used to
perform this training”. The obvious answer is “The aircraft
that is closest to the one that you fly on a daily basis”. If
you fly small piston-powered aerobatic aircraft every day, then you
probably ought to be taught in a small piston powered aerobatic
aircraft. However, if you fly a multiengine jet, you probably ought
to be trained in a multiengine jet. There have been several attempts
to conduct unusual attitude training in light piston engine aircraft.
This poses several issues for the prospective client, among them
being the following: First, a piston aircraft has certain
“vibrancy” as airspeed is increased. Airframe noise,
propeller noise, airframe vibration, and other sensory inputs allow
pilots to be “airspeed aware” without reference to flight
instruments. This is in contrast to a jet, where the sensory inputs
are muted, and where the pilot must be able to determine the energy
trend state of the aircraft mainly by reference to instruments.
Second, although piston engine aerobatic aircraft may be capable of
high TRANSIENT G-loads, they are not capable of flying at the higher
jet-speeds, with the resultant increase in maneuvering radius in
pullouts, that result in the need to hold higher than standard G
loads far longer TIME PERIODS than are required for recovery in a
jet. The bottom line is this: In a transport category jet, maximum
pullout G loads even if terrain-strike is probable, assuming that
published airframe limits are deliberately exceeded in order to save
the lives of the occupants, it is probably true to assume that G
loads will not exceed about 4 G, which is actually quite low as
compared to “aerobatic” maneuvering G loads. We have
studied human responses to these situations, and we find that 4 G is
about the level of normal human tolerance for a pilot caught unawares
and not having performed a G-strain maneuver in advance of G-onset.
The issue is that at 300 knots or more, this 4-G state might need to
be maintained for as long as 30 seconds! This sort of sustained G
performance in pullouts is not available to any light aircraft, as it
is purely a function of airspeed during the maneuver to wings-level
condition. Although there are other reasons such as P-Factor,
Slipstream Effects, etc, that the author believes exclude propeller
driven aircraft from effectively conducting “Jet Upset
Training” (which is, after all, JET Upset Training), the twin
issues of “eyes-closed airspeed sensing” and “sustained
G loads” are the two that are most important. Add to that the
fact that the popular model piston engine aircraft used for this type
of training has suffered three fatal in-flight structural failures in
recent years, and it’s obvious that a vehicle selected to
perform this mission must be chosen carefully for both fidelity of
instruction and safety reasons.
Aircraft that are
capable of performing all of the maneuvers that are desirable to
include in a comprehensive course of instruction are limited.
Certificated Transport Category aircraft such as a strongly
constructed business jet would be perfect. Unfortunately, no
correctly qualified operator presently has such an aircraft available
to perform this training, due to initial acquisition costs. As a
substitute, single engine military training-type jets would be
suitable for use-if the pilots flying them are willing to rely on
using an ejection seat as the memory item for “Engine Failure on
Takeoff”! Since most of us are not willing to rely on a
bang-seat as a substitute for a second engine, the obvious choice is
to use a multi-engine jet aircraft that is certified for aerobatics,
which has the FAA required emergency escape capabilities, but which
relies on traditional transport-category, V1/V2 based,
“accelerate-stop, accelerate-go” technique for routine
operations. This theoretical aircraft would allow a corporate or
airline pilot to train in a suitably capable and safe jet aircraft,
while not requiring a “military-like” ejection seat
training course to be taken before flight training to commence.
Fortunately, there
is an aircraft that is available for just such use: The Aerospatiale
CM-170 “Magister”. This is a light twin-engine training jet
manufactured in France, which has an extremely long history of safe
operation by 19 different air forces. These were used by the
Participle de France aerobatic team for many years, and in French
service flew some 2.7 million (yes, MILLION) flight hours without any
structural failures. For this reason, Red Star Aviation has selected
the Magister as the vehicle of choice for performing Jet Upset and
Unusual Attitude training. Our Magister has been modified with modern
angle of attack system so that pilots may learn to use this important
tool in recoveries, as well as having had modern avionics including a
GNS-XLS Flight Management System installed in order to make Corporate
Aviators at home in the cockpit. Apparently, the US Navy agrees with
our assessment that the Magister is the best tool for the job, as
over 200 US Naval Test Pilot School students have flown this aircraft
for a one-hour flight as part of their formal curriculum of
instruction, and each has flown the same exact maneuvers that are
used in our Jet Upset training course.
A note about us:
Red Star Aviation was founded as a Non-Profit Educational Foundation
under IRS Section 501(C)(3) to provide high-quality flight
instruction to professional pilots. As a non-profit educational
foundation, our mission is SAFETY, not profit.
It’s hoped
that this short treatise has sparked your interest in “flying
the real thing”. Feel free to contact us if you have any
questions, or desire to schedule training.
Dave Sutton,
Instructor Pilot, Red Star Aviation
Member: The
Society of Experimental Test Pilots
Safety is our
only goal.
Our Motto:
“If there’s doubt, there’s no doubt”. |
