Harper_R_P_Cooper_G_E_Handling Qualities and Pilot Evaluation

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of the Navy and Air Force Test Pilot Schools in 1960 and 1963, respectively.
Ground simulation followed.
Criteria from Piloted Evaluations
The military flying specification, AAF-C-1815, gave way in 1954 to a new ver-
sion, MIL-F-8785, [28] which incorporated some of the data from early piloted
simulation experiments. These data bases were growing very rapidly, however;
and in 1969, Chalkand associates at CAL, under contract to and working closely
with Charles Westbrook of the USAF Flight Dynamics Laboratory, formulated
a new, almost revolutionary verison of the specification. This version, adopted
as MIL-F-8785B, [29] incorporated the pilot-in-the-loop research results, formu-
lated concepts of flying quality levels of desirability based on the Cooper-Harper
rating scale, aircraft states (including failure states), performance envelopes,
and other concepts to deal with the new world of flight control augmented air-
planes. Another innovation of MIL-F-8785B was an extensive report giving
Background Information, which documented the basis and supporting data
upon which each requirement was based. [30] A revised version, MILF-8785C,
was issued by the USAF in l980 [31] and is currently in use while another revision
is in preparation.
Electronic Flight Control Systems
As we look to the future, it appears that electronic flight control and cockpit
display system technology should be capable of providing whatever the pilot
desires. However, we hear much about the development problems of the sophis-
ticated electronic flight control systems in the YF-16, YF-17, F-18, and Tornado
fighter aircraft, as well as in the Space Shuttle, in that they exhibited serious
and, in some cases, dangerous handling quality problems (pilot-induced oscil-
lations, PlO) which were not predicted by analysis or ground simulation. This
subject has been examined by a number of handling qualities specialists [32, 36]
and a common problem seems to have been excessive time delays introduced
through the design of complex higher-order fly-by-wire (FBW) control systems.
A contributing factor was the unrecognized deficiencies in some simulators or
in the simulation experiments and interpretation of results. A number of im-
portant lessons have already been drawn from these experiences; those directly
related to handling qualities and pilot evaluation are summarized here.
19
1. Flying qualities criteria have not kept pace with control system develop-
ment, in which high-order transfer functions have introduced undesirable
delays.
2. Deficiencies in simulators are often not recognized, thereby adversely af-
fecting the results.
3. The development process should include both ground and airborne flight
simulation.
4. Inadequate communication among the various engineering specialties, man-
agement, and test pilots has seriously compounded the problems of con-
ducting sophisticated simulation experIments.
It becomes increasingly apparent that successful application of new technol-
ogy is critically dependent upon the test pilot s evaluation of handling qualities
and the tools (simulator facility and experiment design) with which he and the
project engineers have to work.
There is certainly nothing in these lessons that cannot be applied to the next
generation of aircraft, if the industry heeds them. It is of interest to note that
the next generation European Airbus, the A-320, plans to adopt new technology
that has not yet been incorporated in a civil transport. [37] In addition to an
advanced fly-by-wire control system, without mechanical back-up, the A-320 will
replace the conventional control column with side-located hand controllers and
will employ a full panel of electronic displays. The success of this development
would appear to rest, in part, on their approach to the above lessons.
We have noted several significant lessons to be applied to the science of flight
simulation. We will next consider guidance and recommendations for engineers
and pilots in the conduct of handling quality evaluations.
Methods for Assessing Pilot-Vehicle System Qual-
ity
AnalytIcal
All of the elements shown in Fig. 1 should be represented or considered when
evaluating the handling qualities of an aircraft. For engineers, the most sat- [ Pobierz całość w formacie PDF ]

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