How Aviation Weathered the Fuel Crisis of the 1970s

The battle of limited supply versus high demand is spilling off the roadway and onto the runway. The price volatility confronting pilots at the pump at general aviation airports has provoked some uncertainty when it comes to travel plans. “The primary driver of the price volatility has been supply disruption,” Muneed Ahmed, director of trading and logistics for Avfuel, a global supplier of aviation fuel and services to the general and business aviation markets, told FLYING earlier this week. 

“Currently, jet-A inventories in the U.S. are at one of the lowest levels since 2000,” he said. 

However, a past crisis helps put the current situation into perspective.

In the U.S., fluctuations of fuel supply levels—no matter how short lived—can be potent enough to conjure ghosts of energy crises past. In the fall of 1973, the U.S. was slapped with an Organization of Petroleum Exporting Countries (OPEC) oil embargo that forced the entirety of the nation to atone for its dependence on foreign oil. 

The crisis was potent enough to spur the creation of the Strategic Petroleum Reserve (SPR), a complex of underground storage caves in salt domes along the coast of Texas and Louisiana. 

"The 1973 oil embargo underscored the need for a strategic oil reserve," said Michelle McCaskill, spokesperson for the Defense Logistics Agency, which purchased the first fill of crude oil for the SPR. "The SPR is a strategic asset for the U.S., serving as an emergency storage reserve for crude oil and fuel. It is the largest emergency supply of oil in the world, holding up to 727 million barrels of oil."

The stockpile is a form of insurance meant to keep the sepia-toned memories of car lines with anxious drivers awaiting rations of fuel stretching around city blocks at bay. The shortages of the 1973 fuel crisis meant drivers had to reprioritize and reconsider non-essential travel. 

On the nation's runways, the story was no different.  

"The PARTY is over," a FLYING staff report said in January 1974, less than three months after the embargo began. "The day of plentiful inexpensive fuel has passed and we have been thrust suddenly into an era of expensive and scarce fuel."

In the early 1970s, cheap fuel was everywhere. It was a fairytale time for travel, and an era that gave birth to aircraft like the fuel-hungry Concorde, an airplane that legendarily burned 2 tons of fuel just while taxiing out to the runway. 

The embargo, which ran from October 1973 through March the following year, hit everywhere across the U.S., especially in aviation. Fuel prices at GA airports went up and rationing set in.  On November 26, 1973, the Presidential Administration proposed that GA fuel supplies would be slashed by up to 50 percent, sparking a run by aircraft owners to sell, FLYING reported at the time. 

At airports, the FAA made efforts to save precious fuel by minimizing ground delays. Air traffic controllers were instructed to clear flights along direct routes when possible and to offer vectors to eliminate airway doglegs. Gate-hold procedures were in place at all major airports, and IFR aircraft were told to stay parked until it was time to fire up engines for takeoff. There was even a short-lived FAA ban on Sunday fuel sales at FBOs. All were efforts to conserve every drop of fuel.

"After one FAA center chief outlined the steps being taken to help conserve fuel, he said there just wasn't much else they could do other than turn the thermostats down to 68, douse the unnecessary lights and form car pools," one FLYING report noted. 

The industry, manufacturers in particular, were forced into a period of introspection. Prior to the crisis, 1974 had the hallmarks of a banner year of sale for aircraft makers, "but the fuel shortage clouded the crystal ball," according to one FLYING report in March 1974. Cessna, for example, was forced to lay off 2,400 workers and downgrade sales projections for the year from 9,000 aircraft to 6,600—yet still a healthy number compared to current production figures.

"Even though all manufacturers will no doubt take a long and critical look at new airplanes [which are expensive to develop], there is no indication that research and development efforts are dropping off the line," FLYING reported. "In fact, the development of more fuel-efficient airplanes might spur greatly increased R&D efforts in many places."

If anything, the fuel crisis that began in 1973 underscored the adage that necessity is the mother of invention.

"There's a real realization in the United States that this emphasis on higher, faster, and farther in flight" needs to be tempered with more fuel efficient initiatives, such as that occurring in the automotive industry, Dr. Jeremy Kinney, associate director of research and curatorial affairs at the Smithsonian National Air and Space Museum in Washington, D.C., told FLYING in a recent interview.

The fuel crisis gave way to innovation, with NASA taking up the challenge of making the airplane and the jet engine more efficient, Kinney explained. During the decade-long Aircraft Energy Efficiency program, NASA set a goal of reducing fuel consumption by 50 percent, through initiatives that improved internal components of engines. It also focused on designing a new engine from the ground up with the goal of decreasing fuel consumption and increasing cruise speeds.

Other advances stemming from the program included lighter materials for aircraft structures, and wing modifications, which moved the industry into earlier applications for realizing potentially significant fuel savings, the General Accounting Office told members of Congress.

"NASA was working with industry," such as Pratt & Whitney and General Electric, "and looking at configurations of these engines and how that actually influences what the manufacturers put into their engines into production," Kinney said. "The idea is to create a new engine, so you're no longer using these classic engines like the JT3D and the JT9D…because they're taking advantage of the materials, the construction, the combustor and turbine design, as well as the controls," such as full authority digital engine control, or FADEC—now found on many modern piston and turboprop powerplants.

"That is a part of the result of this work, to make everything more efficient," Kinney said.

It was technology aimed at minimizing fuel burn that would later contribute to the development of the world's largest turbofan engine, the GE90, Kinney said. About two decades later, General Electric's high bypass turbofan jetliner engine would go on to debut on a Boeing 777.

In the Advanced Turboprop Project, which came along later in 1978, NASA researched how to increase efficiency of what was essentially a propeller-driven turbine engine by about 30 percent, Kinney said. 

In the age of jet engines, reverting back to propellers in the name of innovation was a bold concept. 

"The energy crisis of the early 1970s served as the catalyst for renewed government interest in aeronautics and NASA launched this ambitious project to return to fuel saving, propeller-driven aircraft," according to a NASA document detailing the history of the program. "The Arab oil embargo brought difficult times to all of America, but the airline industry, in particular, suffered and feared for its future in the wake of a steep rise in fuel prices. NASA responded to these fears by creating a program to improve aircraft fuel efficiency."

Research involved 15 university grants, more than 40 industrial contracts, and research at four NASA research centers. The advanced turboprop concepts were so successful that the NASA team won the National Aeronautic Association's top award, the Robert J. Collier Trophy, in 1987. 

"It amounts to a reinvention of the technology, especially for short and medium routes," Kinney said. "This particular project was so ambitious because it was about inventing a new type of powerplant," he said.

Despite the technological success, the turboprop revolution that many foretold was coming never happened because of the lack of public buy-in. 

"From the beginning, it was the perception of an energy crisis, not a technological innovation, that spurred the idea of the project itself," NASA's history of the program recounted in 1998. "As the project progressed, within each technological stage, the engineers used distinctive and creative approaches to deal with the complex web of government, industry, and academic contractors. More often than not, the main question was not does the technology work, but how can we get government, industry, and the public to accept this technology? In the end, it was a socioeconomic issue again which shelved the program. The reduction of fuel prices ended the necessity for fuel conservation in the skies and today the advanced turboprop remains a neglected, or 'archived' technology."

While the application of the project’s findings may have been shelved—and not typically applied to the commuter market—advances in turboprop engines such as the FADEC enabled Pratt & Whitney PT6E series have propelled single- and multiengine GA airplanes to cruise at similar altitudes (up to 31,000 ft), albeit at somewhat slower speeds (up to Mach 0.56 rather than Mach 0.8).

It would be one of many lessons that came from 1973, Kinney said.

"It's a technology that was on a plateau," Kinney said. "Unfortunately, by the time they were getting ready to integrate the design and really invest the money in the development of what the system was and how it worked, fuel prices [went] back down and there was no longer a need." 

The Advanced Turboprop Project was, according to NASA historians, a case study demonstrating "how radical innovation can emerge from within a conservative, bureaucratic government agency." 

It was also part of a movement in the industry where the collective of academia, industry, and the government were focused on not only surviving the oil crisis of 1973, but thriving on the other side of it.

"It united aviation in a way that they had a goal to work toward," Kinney said. "There are many different reasons to improve the airplane, and none better than to save money on gas."