Cooper-Harper rating scale
The Cooper-Harper rating scale is a set of criteria used by test pilot
Test pilot
A test pilot is an aviator who flies new and modified aircraft in specific maneuvers, known as flight test techniques or FTTs, allowing the results to be measured and the design to be evaluated....

s and flight test engineers to evaluate the handling qualities of aircraft during flight test
Flight test
Flight test is a branch of aeronautical engineering that develops and gathers data during flight of an aircraft and then analyzes the data to evaluate the flight characteristics of the aircraft and validate its design, including safety aspects...

. The scale ranges from 1 to 10, with 1 indicating the best handling characteristics and 10 the worst. The criteria are evaluative and thus the scale is considered subjective.


After World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, the various U.S. military branches sent different models of their operational aircraft to the Ames Aeronautical Laboratory
NASA Ames Research Center
The Ames Research Center , is one of the United States of America's National Aeronautics and Space Administration 10 major field centers.The centre is located in Moffett Field in California's Silicon Valley, near the high-tech companies, entrepreneurial ventures, universities, and other...

 located at the Moffett Federal Airfield
Moffett Federal Airfield
Moffett Federal Airfield , also known as Moffett Field, is a joint civil-military airport located between northern Mountain View and northern Sunnyvale, California, USA. The airport is near the south end of San Francisco Bay, northwest of San Jose. Formerly a United States Navy facility, the former...

 in Mountain View, California
Mountain View, California
-Downtown:Mountain View has a pedestrian-friendly downtown centered on Castro Street. The downtown area consists of the seven blocks of Castro Street from the Downtown Mountain View Station transit center in the north to the intersection with El Camino Real in the south...

 for evaluation of the planes' flight performance and flying qualities. The laboratory was operated by NACA
- Organizations :* National Advisory Committee for Aeronautics, the forerunner of the U.S. federal agency NASA* National Association for Campus Activities, an organization for programmers of university and college activities...

, the predecessor of NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

. Most of the flights were conducted by George Cooper, Bob Innis, and Fred Drinkwater and took place at the remote test site at the Crows Landing Naval Auxiliary Landing Field in the central valley area east of Moffett Field.

What may be the most important contribution of the flying qualities evaluation programs and experiments conducted on the variable stability aircraft at Ames was George Cooper's standardized system for rating an aircraft's flying qualities. Cooper developed his rating system over several years as a result of the need to quantify the pilot's judgment of an aircraft's handling in a fashion that could be used in the stability and control design process. This came about because of his perception of the value that such a system would have, and because of the encouragement of his colleagues in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 and England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 who were familiar with his initial attempts.

Cooper's approach forced a specific definition of the pilot's task and of its performance standards. Furthermore, it accounted for the demands the aircraft placed on the pilot in accomplishing a given task to some specified degree of precision. The Cooper Pilot Opinion Rating Scale was initially published in 1957. After several years of experience gained in its application to many flight and flight simulator
Simulation is the imitation of some real thing available, state of affairs, or process. The act of simulating something generally entails representing certain key characteristics or behaviours of a selected physical or abstract system....

 experiments, and through its use by the military services and aircraft industry, the scale was modified in collaboration with Robert (Bob) Harper of the Cornell Aeronautical Laboratory
Cornell Aeronautical Laboratory
Calspan Corporation is a science and technology company originally founded in 1943 as part of the Research Laboratory of the Curtiss-Wright Airplane Division at Buffalo, New York. Calspan consists of 5 divisions: Flight Research, Transonic Wind Tunnel, Systems Engineering, Transportation Sciences...

 and became the Cooper-Harper Flying Qualities Rating Scale in 1969, a scale which remains the standard for measuring flying qualities.


In recognition of his many contributions to aviation safety, Cooper received the Admiral Luis de Florez Flight Safety Award in 1966 and the Richard Hansford Burroughs, Jr. Test Pilot Award in 1971. After he retired, both he and Bob Harper were selected by the American Institute of Aeronautics and Astronautics
American Institute of Aeronautics and Astronautics
The American Institute of Aeronautics and Astronautics is the professional society for the field of aerospace engineering. The AIAA was founded in 1963 from the merger of two earlier societies: the American Rocket Society , founded in 1930 as the American Interplanetary Society , and the Institute...

 to reprise the Cooper-Harper Rating Scale in the 1984 Wright Brothers Lectureship in Aeronautics.

Future replacement scales

While the Cooper-Harper scale remains the only well-established scale for assessing aircraft flying qualities, its unidimensional format lacks diagnostic power and has also been criticised for exhibiting poor reliability. The Cranfield Aircraft Handling Qualities Rating Scale (CAHQRS), developed at Cranfield University
Cranfield University
Cranfield University is a British postgraduate university based on two campuses, with a research-oriented focus. The main campus is at Cranfield, Bedfordshire and the second is the Defence Academy of the United Kingdom based at Shrivenham, Oxfordshire. The main campus is unique in the United...

's School of Engineering, is a new evaluative system that is multidimensional. It was developed by combining concepts from two previously established scales, the NASA-TLX
The NASA Task Load Index is a subjective, multidimensional assessment tool that rates perceived workload on six different subscales: Mental Demand, Physical Demand, Temporal Demand, Performance, Effort, and Frustration...

workload scale and the Cooper-Harper. A series of validation trials in an engineering flight simulator with a range of control laws showed that the CAHQRS was at least as effective as the Cooper-Harper scale. However, the CAHQRS also demonstrated greater diagnostic ability and reliability than the Cooper-Harper. This new scale's acceptance by the aerospace industry at large, though, remains to be demonstrated.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.