Flying by the seat of your pants…

In the beginning.

True instrument flight, i.e., safe flight solely by references to the aircraft instruments lagged behind the development of aircraft by several decades. In reality, there was only one prudent choice—fly only when visibility allowed the pilot to see a horizon.


William C. Ocker

A World War I Army pilot, William Charles Ocker—“the father of blind flying’—nearly died in 1918 while testing an early Sperry turn indicator. He ended up in a steep spiral and only narrowly escaped when he broke out of the clouds with room to recover. It was then that he realized that his senses differed from the turn indicator. It had indicated the turn, but his senses told him he was in level flight. He realized that his “pilot instincts” had failed him.

As David McIntosh points out in his thesis for the USAF Air Command and Staff College (1988) titled “The Evolution of Instrument Flying in the U.S. Army,” there really was no seriously established instrument flight training instruction for the first 30 years of aviation.

In the decade following World War I, the Army found itself firmly in the aviation business, but there was little interest in instrument flying. If the pilot could not see the ground or a natural horizon, there was no need to fly. But forces were building that would demand a change in attitude and training.

At the same time, the first fledgling airlines were growing, and passengers were eager to take advantage of the speed and convenience that air travel offered. However, passengers then, much as passengers today, did not understand why “a little rain” would cause a flight to be canceled. Safe instrument flight was going to be a business imperative for airline success.
The initial instrument flight technique the Air Corps used was called “needle-ball and airspeed” flying. Students were taught that each aircraft control surface (rudder, aileron, and elevator) commanded an individual instrument indication. For example, the rudder controlled the turn needle, the ailerons controlled the bank (ball) indicator, and the elevator controlled the vertical velocity indicator.

By 1929, the first rudimentary training devices were becoming available. Edwin Link built his first trainer. It consisted of a small aircraft replica (including stubby wings and tail section) mounted on a universal Joint. The stick and rudder pedals in the cockpit actuated a set of air bellows that caused the entire assembly to rotate and tilt like an aircraft in flight.
In the early 1930s, the Link trainer, still a very basic simulator, had instruments that showed horizon, turn rate, heading, etc.

In 1934, by an act of Congress, the Army Air Corps was assigned the responsibility of delivering airmail across the country with disastrous results. There were numerous aircraft and pilot losses. The Air Corps was forced to take instrument flying seriously. It increased its training, put instruments in the aircraft and introduced management practices to ensure that all pilots were “instrument capable. Still, instrument flight training was considered a nuisance. Pilots were not well trained, and training was lax.

Meanwhile, Link made instrument training inexpensive and safe, which allowed the Army to provide more of it during the critical pre-World War II period. The Link and its descendants, today’s simulators, played an important role in promoting instrument flying.


An early Link Trainer

General James H. Doolittle was an influential supporter of instrument flight training. He and a partner privately financed the Full Flight Laboratory at Mitchel Field, New York, to research and develop flight instruments and radio navigation and landing equipment.

Doolittle focused his attention on finding a way to land an airplane in dense fog. On September 24, 1929 Doolittle performed the first completely blind flight, taking off, navigating, and landing using only instruments and radio navigation (there was a safety pilot on board).

Doolittle advocated for equipping aircraft with the advanced navigation systems that were becoming available and train airmen to be proficient in instrument flight, meanwhile, his instruments and training were quickly adopted by commercial airlines.

The Air Commerce Act of 1926 was intended to spur commercial aviation development and it worked. The Department of Commerce was in charge of creating airways, airports, navigation facilities, and weather services for airline operations. By the end of the decade, they had created an extensive system of published airways based on radio-navigation beacons, light beacons, emergency landing fields, and weather reporting stations. They also added instrument approach procedures, to allow the orderly traffic flow into airports obscured by clouds. Commercial passenger and mail operations at night and in the weather were becoming routine.

In 1937, the Army Air Corps required many aircraft to be outfitted with instrument hoods, and the Air Corps ordered all pilots to accomplish a minimum amount of instrument flying annually.


Later, more advanced Link Trainers were used to provide “full panel attitude” instrument flight training.

Instrument flying was now seen as a primary skill. The Air Corps was on its way to becoming an all-weather service. The Corps established minimum annual requirements for instrument flying and periodic instrument proficiency flights for all pilots.

In 1939, the Army Air Force (AAF) realized that simulator training would be less costly, and safer than relying on aircraft. They first trained a group of instrument flight instructors using advanced Link trainers. The Link was used primarily as a procedural trainer, rather than simulating flight. Pilots could develop an instrument cross-check and use that information to control and navigate the aircraft strictly by instruments. During World War II, thousands of pilots honed their skills in Link trainers.

In 1943 there was a shift in instrument training that continues to today. Instrument flying was standardized based on the attitude indicator.

The airlines and the Navy were already teaching full panel flying. Col Joe Duckworth, a recalled airline pilot who was a base Director of Training was familiar with the technique and adapted the Navy training program for his AAF students in 1942. The training was so successful that full panel flying was standardized AAF-wide in June 1943.

The new system called the “full panel attitude” instrument flying was much easier to master. Students learned to visualize the attitude of the aircraft using all of the instruments, but especially the artificial horizon. Control movements were presented in terms of changing the position of the airplane.

The certification process also became more complex than simple check rides. It included a twelve-hour flying training course; a written examination; and a check flight covering basic maneuvers, navigation procedures, and instrument approaches. There were two levels, of instrument certification: Form 8 (White) for less experienced flyers and Form 8 (Green) for the more experienced. To qualify for a green card, pilots had to have a minimum of one hundred hours of actual (not hooded) instrument time. Green card holders also had to take a more demanding check rides than white card holders.

Training was concentrated; once they started instrument work, students had to complete one hour of instruments per day until they were proficient, after which they had to fly instruments at least one day per week. This practice of concentrating training and managing continuity remained a feature of post-war pilot training.

In 1947, instrument flying was a basic skill for all pilots, and the technique of instrument flying was based on the attitude indicator.



The full motion simulator contains everything in the real aircraft cockpit and can simulate most flight conditions, including emergencies, and train pilots in all procedures to qualify in the aircraft type.

After the end of World War II, simulation shifted to procedural simulators that did not move like the Link trainers. Simulators duplicated every detail of the aircraft to be trained in, and pilots could practice all procedures from start to engine shutdown as well as navigation and approaches to any airport.


Advanced visual systems add to the realism of training in full motion simulators.


The first airline simulator was manufactured by Curtiss-Wright for Pan American Airways.

The Boeing 377 Stratocruiser did not move and it had no visual system, but the cockpit was completely simulated down to the last detail.

Using an analog computer, the crews were able to perform all operational procedures, navigation, and train for emergencies.
In the 1960s, with the development of commercial wide-body aircraft, the development of increasingly sophisticated full-motion simulators became the standard for training. Three-axes—pitch, roll, and yaw—motions were augmented with an up-and-down motion. The simulator could be precisely controlled and the modern motion system advanced far beyond simple instrument flight trainers.

In the 1970s, computer-generated graphics made their way into the simulators. With the progress of computer technology, three-dimensional landscapes were developed. Now, the simulator landscapes of today are almost indistinguishable from the real world.
Today, full flight level simulators have all aircraft systems that are accessible from the flight deck and are critical to training. In fact, a pilot can complete most, if not all requirements for a type rating in the simulator.


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