Aircraft Safety: Cracks Begin to Show in the System

Air travelers, unaware and unsuspecting, face a hidden, potentially catastrophic peril.

Airline passengers are less safe today than they were five years ago. And, if current trends continue, they will be at even greater risk a year from now.

With every passing year, the average age of the planes that carry them is increasing. Advancing age makes these planes more likely to crack. And the nation’s airlines are spending less to find and fix those cracks.

At the same time, the airlines are filing fewer legally required reports on structural defects, providing additional strong evidence that they are not finding the cracks. Since the government relies on such reports to evaluate the health of commercial aircraft, the decline has crippled the nation’s already deficient early warning system against air crashes caused by structural failure.

In the face of these developments, the Reagan Administration has let the task of holding the airlines to minimum safety standards outgrow the number of inspectors assigned to do the work--a job of policing that has burgeoned with each new airline and every airline expansion since deregulation.

“Altogether, it’s a formula for disaster,” said Jerry J. Presba, one of three aircraft engineering and maintenance experts hired by The Times to analyze reporting and spending on structural maintenance performed by the airlines over five years. Their analysis was part of a six-month investigation by The Times into the structural airworthiness of the U.S. commercial air fleet.

The investigation focused on the six types of aircraft that make up the preponderance of the fleet. They are the Boeing 727, 737 and 747; the McDonnell Douglas DC-9 and DC-10; and the Lockheed L-1011.

The Times found that:

The average age of each of the six types of aircraft has climbed every year from 1980 through 1984. By the beginning of 1985, all six were approaching or had passed the midpoint of what the Boeing Co. considers their economic lives.

Cracking caused by metal fatigue in the frame and skin of heavy jetliners increases sharply as the planes get older. Data obtained from Boeing shows that this cracking begins to grow at the midpoint of each airplane’s economic life.

Despite the increasing likelihood of cracking caused by advancing age and metal fatigue, the amount of money the airlines are spending to find and fix cracks has dropped over the five years from 1980 through 1984 for all six types of aircraft. This drop is documented in records filed by the airlines with the federal government.

Fatigue-crack reports filed with the government also have dropped. Information in these reports, called Service Difficulty Reports (SDRs), serves as the FAA’s early warning system against aircraft crashes caused by structural failures.

The drop in SDRs correlates with an overall decline in the number of orders from the FAA to inspect for specific cracks and repair them.

Arrayed against these downtrends is an FAA inspector force that has been shrinking in relation to the size of the air fleet. In 1979, the inspectors numbered 2,012. By 1984, because of budget cuts by the Reagan Administration, the number had dwindled to 1,332. During the period, the number of commercial airlines grew from 237 to 407.

Such trends erode the airworthiness of the fleet and cause a corresponding decline in air safety.

The aircraft and airline industries reacted sharply to The Times’ findings.

Thomas Tripp, spokesman for the Air Transport Assn., which represents 33 major air carriers, said the question “is whether the industry has less of a commitment now to maintenance and to safety than it did years ago. . . . Certainly, it’s not true for ATA carriers.”

However, many aviation experts around the nation said the findings confirmed their own views.

“We (also) saw a trend towards trying to get by with less quality maintenance,” FAA Administrator Donald D. Engen acknowledged in an interview. “We’ve nipped that in the bud . . . and we should see that trend reverse itself.”

C. O. Miller, one of the nation’s leading air safety consultants and former chief accident investigator for the National Transportation Safety Board, said he is concerned that the worst consequences are yet to come. “You have had wholesale dilution of the safety effort,” Miller said.

“I see an erosion of safety margins everywhere,” Miller declared. “Your (new airlines) don’t have anything to erode from. They are only meeting the minimum standards anyway. The new guys are so strapped financially that they are not going to go above the minimums.”

FAA Administrator Engen agreed.

“I would be less than candid,” he told The Times, “if I didn’t acknowledge that your SDR figures lend some credence to that.”

Deregulation

The drop in maintenance spending appears to be a consequence of the U.S. government’s decision to deregulate the airline industry.

In 1978, the federal government suspended regulations that set ticket prices and allocated routes. Soon, new non-union airlines with lower wages and overhead forced ticket prices down and saddled several major airlines with multimillion-dollar losses. Some of the older airlines went bankrupt.

The industry as a whole tumbled into economic chaos. Before, it had the stability it needed to plan maintenance investments years into the future. Now, its carriers are engaged in day-to-day survival. Government regulation had permitted the biggest carriers to build large maintenance organizations with huge engineering staffs and enormous capital investments in both plant and equipment. Now that has become impossible.

Before deregulation, for instance, United Airlines built a central maintenance base that employs 7,000, including an engineering staff of 982. The airline repairs its own electronic equipment, and it sews its own seat covers. When United pilots have problems during flight, they can call the maintenance base and discuss these problems with engineers who are experts in every area. New, start-up airlines don’t have these capabilities. In many cases, they do not employ a single engineer. They contract out their maintenance to older, larger airlines, or to aircraft service stations.

“The capital investments to build up those (older, larger) facilities will never exist again,” said Roger Knight, flight standards division manager at the FAA’s regional office in Fort Worth, Tex. “Carriers coming along aren’t going to build those kinds of facilities. They’ll never have the resources to do it. They are going to have to rely on the existing plant created before.”

Deregulation, said James M. Dimin, another of the maintenance experts retained by The Times, “has been a disaster both in terms of its effect on maintenance practices and, ultimately, in its effect on safety.”

In addition to concern over facilities, some experts worry about a lack of experience that new operators bring to the industry.

“You have a lot of non-aviation people owning these airlines and making decisions for their companies,” said Robert W. Baker, senior vice president for operations at American Airlines. “The United Airlines, TWAs and Pan Ams have been around for 50 or 60 years, and the people at those companies have been around for years and years. Under deregulation, anybody who hasn’t committed a felony could get into the airline business.”

In defense of deregulation, some in the airline industry and the government note that fatality rates in air travel were higher before 1970 than they have been since. Safety experts, however, say that can be misleading.

“The FAA and industry reaction sometimes seems to be that you need an accident to know there is a problem,” said Miller, the safety consultant and former NTSB accident investigator. “If you need an accident to know you have a problem, then you are part of the problem.”

Sen. Nancy Landon Kassebaum (R-Kan.), chairwoman of the Senate aviation subcommittee, noted that last year’s rash of accidents in the United States and around the world made 1985 the worst year in world aviation history and one of the worst in the United States since deregulation.

“The deaths have been so enormously high,” she said, “I think we have become very conscious today of things that have caught up with us since deregulation.”

The Drop in Reporting

Aircraft manufacturers know that eventually their planes will crack.

Thus, for the last 30 years, the FAA has certified the structural airworthiness of commercial jetliners under a “fail-safe” design philosophy. It requires an airframe to be strong enough to carry at least normal flight and ground loads even when one of its members is ruptured.

But long before major structural parts of an aircraft fail, periodic inspections are supposed to find the inevitable cracks in them.

Hence, the key to the fail-safe system is inspection. This is especially true since, as an aircraft ages, metal fatigue accumulates, and parts begin to crack at an accelerating rate. “Cracks get more serious as time goes on,” Isaac H. Hoover, the third of The Times’ maintenance experts, said.

The trend of this cracking over an airplane’s life follows what is known as the “bathtub” curve, so-called because its shape resembles that of a bathtub. (See graphs below.)

The line of the curve charts the rise and fall in the number of cracks a typical fleet of aircraft experiences over its lifetime. There is an initial surge in cracks during the first six months to a year that an aircraft enters service. This is a period of “infant mortality,” in which manufacturing glitches are worked out of the product, Hoover said.

After 10 years of typical service, most aircraft fleets experience fatigue damage at an accelerating rate. At 20 years, according to the bathtub curve represented in Boeing technical reports, the rate of damage has turned significantly upward.

“For all fleets, the general shape of the curve is the same,” Ulf Goranson, manager of structural damage technology at Boeing, said in an interview. “It has a fair amount of validity.”

J. A. McGrew, chief technology engineer for airframes at McDonnell Douglas, agreed in principle: “You fly the same aircraft more and more, you would expect to find more problems. Nobody will argue with that.”

“I would expect any aircraft to have increased cracking as it gets older,” concurred Elliott Green, a Lockheed vice president who was chief engineer on the L-1011 program. “There is no question about the fact that as an airplane ages, you will get more corrosion and more fatigue cracks.”

And, indeed, airplanes in the United States’ commercial fleet are aging.

Middle age is approaching or has passed for all six aircraft types. For example, the average age of 727s went from 9.05 years in 1980 to 12.16 years in 1984; and the 747 went from 7.68 to 11.4. For all six planes:

AVERAGE FLEET AGE

Aircraft 1980 1981 1982 1983 1984 727 9.05 9.59 10.50 11.81 12.16 737 8.21 8.88 8.76 8.84 8.44 747 7.68 8.73 9.70 10.64 11.40 DC-9 10.68 10.82 11.66 11.19 11.75 DC-10 6.29 7.08 8.10 8.95 9.84 L-1011 5.62 6.10 6.67 7.56 8.33

Since these are average ages, many aircraft of each type are well past the 10-year midpoint of their economic service life as defined by Boeing. In the 727 category, for example, more than 80 aircraft now flying in the United States are over 20 years old.

Thus, each of the fleets has at least some aircraft that should be on the upward slope of the bathtub curve. They should be experiencing increased fatigue cracking, triggering an increase in Service Difficulty Reports to the FAA.

However, when The Times studied SDRs for the years 1980 through 1984--the last year for which complete data is available--it found that the number of reports did not increase as it should have.

In fact, for five of the six aircraft, the trends dropped. For the DC-9, for instance, SDRs per aircraft declined from 1.82 in 1980 to 0.65 in 1984. Only the 747 showed an increase. For all six planes:

STRUCTURAL PROBLEMS

Structural Service Difficulty Reports per aircraft.

Aircraft 1980 1981 1982 1983 1984 727 .760 0.61 0.38 0.36 0.46 737 1.82 2.18 1.56 2.46 1.21 747 1.27 1.24 0.97 1.28 1.43 DC-9 1.82 1.76 1.64 0.99 0.65 DC-10 0.74 0.51 0.32 0.29 0.29 L-1011 1.02 1.24 0.73 0.62 0.58

Because Service Difficulty Reports sometimes prompt the FAA to issue Airworthiness Directives ordering repairs, the drop in SDRs might mean a similar drop in ADs. This would mean that, as planes grow older and more likely to crack, the FAA might be issuing fewer orders to find the cracks and fix them.

The Times reviewed ADs issued in each of the five years for each of the six aircraft types and selected those that called for inspection and repairs on structural components. These were tabulated.

The results correlated with the SDR findings. As the six aircraft advanced in age, only one showed an increase in ADs--the 747.

The Loopholes

In an order issued Feb. 22, 1978, the FAA made it clear to all of its regional and district offices, which deal firsthand with the airlines and aircraft maintenance stations in their areas, that every malfunction, failure or defect in 16 categories specified in federal law must be reported in SDRs every time they occur.

But McGrew and Kenneth Peterson, the chief systems technology engineer at McDonnell Douglas, said some of the FAA regional and district offices enforce the order--and others do not.

“With SDRs,” Peterson said, “you don’t have any homogeneous coverage.”

Worse, says an analyst at the FAA’s Safety Data Branch who asked to remain anonymous, SDR regulations themselves leave the airlines a loophole.

Apart from the 16 categories and “major repairs,” federal regulations on SDRs leave it up to each airline to report other mechanical failures only if “in its opinion” they are dangerous. “Because of this loophole,” the analyst said, “any airline can say of whatever isn’t specified, ‘In our opinion, this particular thing isn’t dangerous.’ And then it doesn’t have to report it.”

Thus, aircraft manufacturers have developed their own systems for acquiring information about structural defects and failures. They encourage customer airlines to report problems directly to them. “The number of reports that Boeing gets from the airlines is greater by orders of magnitude than the number the FAA gets,” noted Ulf Goranson, the structural damage technology manager at Boeing.

Nonetheless, the aircraft maintenance experts retained by The Times say the SDR system is an acceptable data base for a study of trends.

The system has not changed significantly over five years, Isaac Hoover noted. “And I do not think anyone can claim,” he said, “that there has been any major change in the practice of reporting SDRs.” Since problems with the system and with the way it is used have remained constant, Hoover said, a decrease in SDRs over five years most likely reflects a decline in actual reporting--not any deficiency in the system.

Moreover, the Air Line Pilots Assn., a union representing 34,000 pilots who fly for 47 airlines, thinks that maintenance reporting is in fact even more deficient than The Times’ findings indicate.

Because SDRs tend to encourage underreporting, said John O’Brien, ALPA’s engineering and safety director, “if we had all the data, the case would actually be worse than what you are showing.”

The Drop in Maintenance

To determine whether decreases in SDRs and ADs reflect merely a decline in reporting or, more significantly, a downtrend in inspections--and, consequently, inattention to structural repairs--The Times also investigated airline spending on structural maintenance over the same five years covered by the SDRs and ADs.

Despite the increasing likelihood of structural cracking because of advancing age, The Times found that spending by airlines for structural inspection and repairs has dropped over the five years for each of the six aircraft types. For example, cash spending on the 747 fell from $175.64 per flight hour to $152.55. On the L-1011, expenditures declined from $165.33 per flight hour to $139.03. For all six planes:

MAINTENANCE SPENDING

Annual structural maintenance spending per flight hour.

Aircraft 1980 1981 1982 1983 1984 727 $42.34 $43.20 $37.16 $39.88 $42.87 737 80.79 67.97 59.32 67.42 65.99 747 175.64 171.59 137.30 140.37 152.55 DC-9 76.66 80.82 72.58 71.33 69.18 DC-10 153.06 153.48 118.16 123.66 111.06 L-1011 165.33 153.62 139.81 129.78 139.03

These decreases in spending for structural maintenance have come at a time when airline revenue has been increasing. Air Transport Assn. figures show that total operating revenues for U.S. scheduled airlines climbed from $33.7 billion in 1980 to $43.8 billion in 1984. Airline profits fell from $17.4 million in 1980 to net losses of $915.8 million in 1982--but then climbed back up to net profits of $824.7 million in 1984.

As a percentage of total operating expenses, maintenance overall has decreased from 8.85% of airline budgets in 1980 to 7.6% in 1984. These Department of Transportation figures include all spending on inspection and repairs of engines, hydraulic systems and avionics as well as structures.

To some, these figures suggest a disturbing conclusion about the maintenance practices of many airlines.

“They are shaving corners,” declared Frank Celona, assistant airline coordinator at the International Assn. of Machinists, which represents airline mechanics. “They are trying to get by with what they can. There’s no question about it. The air carriers are looking for means to cut costs, and one of the most expensive areas is maintenance. That’s where they want to cut. And the FAA has gone along with them.”

A 1984 Labor Department survey shows that the airlines cut more than 4,300 mechanics at line stations along their routes between September, 1980, and June, 1984. Although the airlines added mechanics at their maintenance depots, the additions were too few to make up the difference. Overall, the survey shows, the number of mechanics employed by airlines decreased by at least 3,000.

The Air Transport Assn. acknowledges a drop of 2,000 mechanics between 1974 and 1984 at scheduled airlines. During the same period, ATA figures show, the number of planes flown by all scheduled, supplemental, commuter, air taxi and cargo carriers climbed by more than 1,700 aircraft.

Rep. Norman Y. Mineta (D-San Jose), chairman of the House aviation subcommittee, expressed surprise at the downtrends in maintenance spending. If the SDR system were being used properly and if structural maintenance were up to par, he said, “it just doesn’t seem logical that those numbers would seem to be going down.”

Maintenance spending and SDRs for the L-1011 and the DC-10, at least, because of their age, should be going up, said John Enders, president of the Flight Safety Foundation, which is funded in part by the airlines. “It raises a lot of questions in my mind.”

John O’Brien, the engineering and air safety director at the Air Line Pilots Assn., said the decreases in SDRs and in spending on structural maintenance show that airlines “are not reporting cracks they find, and they are not finding cracks that must exist.” He cited analogous cutbacks in maintenance on flight equipment.

“It’s because of the competitive environment,” O’Brien said. “It’s more so now than five years ago. We get calls about it from pilots several times a week.”

It is possible, he said, to operate an aircraft safely only if it is properly maintained.

“You cannot say this is just an aging aircraft problem,” O’Brien said. “The problem is the capability or the willingness to inspect and maintain. You may not be capable of doing what is necessary because of the competitive environment. Or you may not be willing. You may think profitability is much more important.

“I’m not saying every airline is in this situation. Delta, Northwest--they’re not having maintenance problems. But for every Delta and Northwest that is doing well, you can find five or six that are not doing well. And we are raising the overall exposure to accidents and to incidents if this kind of trend continues.

“Obviously, there already is some erosion of the airworthiness of the fleet.”

The Industry

When presented with The Times’ findings, McDonnell Douglas and Delta charted trends in ADs and maintenance spending for more than five years. J. A. McGrew at the manufacturer described the longer-term trends shown on these charts as “pretty stable.” But in more recent years, the industry charts, like those of The Times, showed decreases in maintenance spending.

Spokesmen for airlines and manufacturers offered these explanations for the downtrends in maintenance:

1. Better preventive maintenance and aircraft design.

“If the airlines fix a problem before it becomes more costly, the costs of maintenance go down,” said Ulf Goranson at Boeing. In addition to early fixes, said D. P. Hettermann, senior vice president for technical operations at Delta, airlines and manufacturers improve aircraft both during and after production to reduce maintenance. Elliott Green at Lockheed and Robert Wallace, maintenance and ground operations systems manager at Boeing, cited improvements in corrosion prevention.

“We’re building airplanes better,” said Kenneth Peterson at McDonnell Douglas.

But nobody suggested that either preventive maintenance or design improvements immunize aircraft from the course of aging represented by the bathtub curve, which makes every plane more likely to develop cracks as it grows older.

2. Increased maintenance efficiency and productivity.

“Cost-cutting is part of our corporate life,” said Richard Tabery, senior vice president for maintenance operations at United. “But at United, we achieve cost reductions through improved technology or a smarter approach to doing our tasks.” Airlines, said Robert Wallace at Boeing, “are able to do maintenance with fewer maintenance hours, because cost-saving measures have made aircraft upkeep more efficient.”

However, airlines and aircraft manufacturers agree that the ways to find structural cracks are limited. They cite visual inspection, X-rays and the use of electrical current, sound waves or penetrating dye. Asked to name recent developments in technology or methodology that improve on these ways, Anthony Broderick, FAA associate administrator for aviation standards, was unable to do so.

So were Hettermann at Delta and Goranson at Boeing.

“Safety depends on detection,” Goranson acknowledged. “Yes, it’s labor intensive.”

Every method of inspection, said Frank Celona of the International Assn. of Machinists, “still requires some kind of visual look-see.” He said improvements in efficiency and productivity cannot account for the downward trends in maintenance spending.

“If that were the case,” he said, “I don’t know why, at every round of bargaining, the airlines come in and want all of these work-rule changes.”

3. Extensions in heavy maintenance intervals.

“Experience allows you to extend some of the times between maintenance checks,” said Robert Baker at American. More time means fewer inspections, Baker said, and fewer inspections mean less spending for maintenance.

“We do a sample, an L-1011 landing gear, for instance,” Hettermann said. “We started with a 6,000-hour maintenance interval, say. So we pull the gear. And, predicated on what we find on that gear, we move the interval out to 8,000 hours. And we will sample again. And, perhaps, with proper maintenance, we move it on out to 13,000 hours. And costs go down.”

Goranson, the structural damage technology manager at Boeing, defends such extensions.

“Strictly maintenance to have maintenance is not good,” he said. If a man goes over a wing from one end to the other every day and finds no cracks, Goranson said, “he is going to start thinking about his girlfriend or about whether it’s going to snow. He won’t keep his mind on what he’s doing, and he’ll starting missing cracks that do exist.”

But Goranson and Robert Wallace at Boeing caution that there also is potential for abuse. Extensions must be approved by the FAA’s Principal Maintenance Inspector (PMI) assigned to each airline. “A lot of it,” Wallace said, “depends upon the relationship between the PMI and the airline. If the PMI wants to be real loose, then. . . .”

“I am sure,” Goranson said, “there is some looseness among some PMIs.”

Safety consultants point out that extensions can be an indirect way of cutting corners.

“There is a hell of a lot of negotiation that goes on between the FAA and the airlines over what is an allowable maintenance program,” said C. O. Miller, the former chief accident investigator at the National Transportation Safety Board. “Within your five years, I’m willing to bet that airlines have gone to the FAA and told them, ‘We’ve got good experience with this or that part, and let us defer maintenance.’

“What they are doing when they do that is coming in and selling maintenance reductions.”

To Sen. Kassebaum, none of these three explanations is persuasive. “I am not convinced,” she said, “that there isn’t corner-cutting.”

Donald Engen, the FAA administrator, said of The Times’ study: “It bothers me. It bothers me. . . . I will look at our own figures. It is of concern to me.” He acknowledged that some airlines have been cutting corners.

“I hate to make it that black and white,” Engen said, “but look at the actions that we have taken with respect to operationally constraining airlines. Fifty-two of them in the last 20 months. In past years, you know, the FAA did two or three a year.

“You can see the actions we are taking, and there must be a reason.”

The Consequences

Three recent developments show consequences of an aging fleet and declining expenditures for maintenance:

An intensive “white glove” inspection of more than 300 of the nation’s airlines revealed what a government task force called a “high rate” of non-compliance with FAA standards.

A subsequent series of special evaluations, or “audits,” at several of the major airlines resulted in procedural changes and fines, including a record $9.5-million proposed assessment against Eastern Airlines and a $1.5-million fine against American Airlines.

Most recently, cracks that could have caused catastrophic failure were discovered on Boeing 747s. The cracks triggered an emergency order by the FAA for mandatory inspections, which turned up even more cracks.

The first of these developments, the “white glove” inspection, began March 4, 1984, and lasted 90 days. It was called the National Air Transportation Inspection, or NATI.

In Phase I, more than 766,000 items and systems were inspected at 327 airlines and 25 air transportation support firms. Despite advance word that the inspection was coming, 43 airlines were singled out because inspectors found that their compliance with FAA safety regulations warranted more intensive Phase II investigations.

To analyze the results, the FAA assembled a task force of retired federal inspectors who computerized 13,634 inspection reports on 303 of the airlines. Here is how various airlines fared:

THE FAA’S REVIEW

Each airline is listed alphabetically along with 1--the number of inspections it received (generally determined by how many types of aircraft it flew and how many FAA regions it operated in); 2--the number of severely adverse comments it got; and 3--its rate of severely adverse comments per inspection expressed as a percentage.

The major airlines:

1 2 3 American 450 21 4.7 Continental 271 59 21.8 Delta 433 57 13.2 Eastern 384 82 21.4 Flying Tiger 114 30 26.3 Northwest 238 20 8.4 Pan American 184 80 43.5 Piedmont 170 11 6.6 Republic 315 20 6.3 TWA 283 13 4.6 United 384 52 13.5 US Air 336 42 12.5 Western 113 11 9.7

A sampling of others: 1 2 3 Air California 43 9 20.9 Alaska 66 12 18.2 America West 51 4 7.8 Braniff 184 14 7.6 Frontier 113 15 13.3 Jet America 35 9 25.7 Muse 41 4 9.8 New York Air 88 3 3.4 Ozark 158 2 1.3 People 129 46 35.7 PSA 50 7 14.0 Southwest 113 13 11.5 World 34 8 23.5

The task force concluded that the “white glove” inspection showed “a less-than-desirable overall industry compliance posture.”

It blamed “poor quality carrier management.” In its final report, the task force added that “air carrier management is ultimately responsible for assuring compliance with the safety standards provided by the Federal Aviation Regulations and other established good/safe operating practices--and therefore should be held accountable.”

Of the 43 airlines that were given in-depth Phase II inspections, 16 were penalized. Some had their operating certificates revoked or suspended. Others surrendered certificates, grounded aircraft voluntarily or withdrew pilots from service. Still other airlines had restrictions placed on their expansion.

More recently, in the second significant development, the FAA has begun special evaluations that have gone beyond the “white glove” inspections.

These special “audits” have been conducted at a number of the larger carriers, including Continental, United, Western, Eastern, Northwest and American. Results have included changes in maintenance procedures, repair manuals and record keeping. In some cases, the government assessed penalties.

The largest proposed fine was a record $9.5-million against Eastern, and the largest fine actually levied was $1.5 million against American. Eastern is contesting the size of its penalty.

FAA inspectors investigated Eastern between Dec. 3, 1985, and Feb. 20, 1986, and said they found 78,000 violations, including improper deferral of maintenance, failure to conduct inspections or make repairs, failure to maintain proper records, flights without the minimum required equipment and failure to follow maintenance manuals.

Among its infractions, Eastern was reported as having used landing gear on several Boeing 727 flights that should have been removed from the fleet. The gear on one plane reportedly collapsed during a landing, but no one was hurt. Eastern officials were said to have responded that 60% of the charges were inaccurate.

Since the investigation, FAA officials have said the problems at Eastern, which sold out last month to Texas Air, have been corrected. Inspectors said they are now satisfied with the safety of its operations.

American’s fine followed a series of incidents that included:

An engine that fell off an American 727 after it was hit by a chunk of “blue ice” from disinfectant which had leaked from a faulty toilet and frozen in high-altitude flight. The investigators found that American had not repaired the toilet despite reports for five months that it had been leaking.

A wing slat that fell from an American DC-10 as it landed at Dallas-Fort Worth. The investigators blamed the problem on the use of plastic pulleys. They discovered that American had installed plastic pulleys instead of aluminum pulleys on three of its DC-10s.

The investigators discerned a larger problem behind these incidents. “I don’t think American Airlines consciously decided to cut back on maintenance,” said Roger Knight, the flight standards division manager at the FAA’s regional office in Fort Worth, which has jurisdiction over American’s maintenance operation. Instead, he cited American’s growth--estimated at nearly 20% annually. Like other airlines, Knight noted, it adopted hub-and-spoke scheduling between outlying airports and its central operations.

“If you go to a hub operation,” Knight said, “you have to have on-time departures. And the system was not able to provide for the maintenance on a day-to-day level at those hubs. The outlying airports, where some of the aircraft were spending the night, did not have the capability to provide the necessary maintenance. The capability was at the hubs, where the aircraft may spend only an hour in a turnaround. And there is only so much maintenance you can do in an hour.”

American has acknowledged that during its 20% growth it increased its maintenance workers by only 7%.

“The instant that I gave American Airlines their fine,” said Donald Engen, the FAA administrator, “I saw reverberate throughout the entire industry a desire for greater compliance. And I saw mirrored in other airlines out there their determination that they weren’t going to be caught like that.”

To this day, however, American is reluctant to say that it did anything wrong.

“Many of the things they found and objected to were items of interpretation and items of record keeping,” said Robert Baker, the senior vice president for operations. “They did not find anything that jeopardized the airworthiness of this airline’s fleet.”

Finally, in the third and most recent development, Boeing engineers who were modifying a 747 for a customer airline early this year discovered three cracks in adjacent fuselage frames. One was below the cockpit window, the second right above it and the third at the top of the airplane’s characteristic hump. Boeing contacted operators of similarly aging 747s--and found three more planes with cracks.

On Jan. 31, the FAA issued an emergency Airworthiness Directive to all 747 operators. It said the three adjacent fuselage frames in the first plane had been “found essentially severed” and added that “failure of adjacent frames could lead to rapid decompression of the fuselage and possible loss of the airplane.” The AD said the cracks in the other three aircraft were found between the windows and the floor of the first-class section just below the cockpit and about 25 feet behind the nose.

The four cracked planes were being flown by Pan American, TWA and British Airways.

Discovery of the cracks indicated, the FAA said, “that current inspection intervals are inadequate to assure continued airworthiness.” Cracks, the agency said, “could exist on other 747s.” As a consequence, the AD ordered a special inspection of all 747s that had flown 10,000 flights or more. The order applied to all U.S. airlines with 747s and all overseas carriers that use 747s to serve U.S. cities.

Up to 160 aircraft were affected, the FAA said.

The AD said all 747s which had logged 10,000 to 14,000 flights had to be inspected within the next 50 flights, and all 747s that had logged 14,000 flights or more were to be inspected within the next 25 flights. The AD required close visual inspection of the aircraft skin--and further inspection under the skin if it showed signs of trouble with the frame.

British Airways began a detailed examination of its entire 28-plane 747 fleet. The airline stripped the interior of all first-class sections to look at the frames close-up. Other airlines followed suit. And by Feb. 17, the internal inspections showed cracks in 19 parts of the structures on 12 aircraft.

Now the FAA has made such internal inspections mandatory.

By the end of February, Japan Air Lines, which had been conducting a separate inspection of five of its 747s after a crash last August that killed 520 people, reported it had found scores of cracks in all of them. Each of the planes had logged more than 15,000 flights. There were between 73 and 88 cracks in each.

Most of these, too, were in the front of the fuselage between the nose and cockpit.

The Inspectors

Against these downtrends in maintenance spending, the FAA is pitting an inspector force that has been shrinking in relation to the size of the air fleet.

Figures compiled by the Air Line Pilots Assn. show that in 1979 the FAA had 2,012 inspectors assigned to 237 large airlines, commuter airlines and air taxi operators. By the end of 1982, the ALPA figures show, the Reagan Administration had cut the number of inspectors by 14% to 1,735--while the number of airlines, commuters and air taxis had increased by 64% to 389.

By March of 1984, the number of inspectors had been reduced even further--to only 66% of the 1979 force, or 1,332. At the same time, the number of airlines, commuters and air taxis had increased again--to 72% more than the number in 1979, or 407. Although there was a slight climb in the number of inspectors last year, they continued to lag 27% behind the total six years earlier, while the number of air carriers was 122% greater.

“In addition,” pointed out Louis McNair, ALPA’s executive central air safety chairman, “consider that, for each new operator, two FAA inspectors must devote full time, for a period of approximately 45 days, to certifying each new entrant’s maintenance, training and flight operations.” Between 1980 and 1985, McNair said, the FAA certified 76 new large carriers and 233 new commuter airlines. This meant, he said, that FAA inspectors devoted about 27,000 man-days just to certifying new operators.

While inspectors are certifying new airlines, McNair said, “their normal duties cannot be performed.”

To take up some of this slack, he said, the FAA has shifted some of its private aircraft inspectors, called “general aviation inspectors,” back and forth between commuter operators and air carrier operators. But their new jobs, McNair declared, “put them far beyond their level of experience.”

Pilots, he said, “have been reporting to us for a number of years that they see more and more maintenance discrepancies being deferred for longer periods of time.”

Last summer, the General Accounting Office, an investigatory arm of Congress, found that FAA inspections were erratic at best. Between September, 1983, and October, 1984, the GAO noted, the FAA inspected electronics maintenance records 71 times at Ransome Airlines, which flies along the East Coast, and did not conduct a single similar inspection at Flying Tiger, a cargo line based in Los Angeles, even once--although Flying Tiger has five times as many aircraft.

The GAO cited a number of similar instances.

“Some carriers are falling through the cracks,” said Rep. Mineta and Rep. William Lehman (D-Fla.), chairman of the House transportation subcommittee, in a letter to the FAA. Mineta proposed adding 200 inspectors and 100 support staff. “When we deregulated domestic route entry and fares,” Mineta said, “the Congress did not deregulate the safety standards.”

Shortly afterward, the Administration proposed a similar increase in inspectors. The proposal won airline industry support.

Members of Congress and the Administration have talked about making even more increases later, but McNair at ALPA doubts that the increases will be enough.

“In order to provide the same capability that existed in 1979,” he declared, “we need an additional 2,453 inspectors.”

That total exceeds anything the Administration has mentioned by nearly 2,000.

Worse, the FAA, like other government agencies, is facing cuts mandated by the Gramm-Rudman deficit-reduction law.

Administration officials have said some domestic programs will have to be cut by 20%.

“I can visualize no reasonable way in which the FAA could absorb that kind of reduction overall,” Engen, the FAA administrator, told Sen. Kassebaum’s subcommittee last month. There would be “serious deterioration of the current levels of safety services we provide,” the administrator said.

“I don’t think a 20% cut in aviation safety,” Engen said, “is a viable option.”

THE CASE OF THE 747

Severe cracks have been found in the fuselage frames on aging Boeing 747 aircraft. The cracks have prompted the government to order an emergency inspection and repairs. The area in question is the flat part of the fuselage near the front of the plane, just below the first- class passenger seating.

Officially, Boeing attributes the cracks to structural fatigue. But one Boeing official suggests that they are caused in part by the fact that the 747 fuselage is not round. “We put the hump on top of it for an Air Force contract we didn’t get, and that gave it flat sides. They are a ‘hard part’ in the design that were going to get some cracking. Sure as hell, now they have.”

These charts compare the advancing age of the 747 and the decrease in maintenance spending on the 747 fleet.

As 747s get older, these charts are expected to climb. The average 747 fleet age should go up. Service Difficulty Reports (SDRs) on structural cracks should increase. Money the airlines spend to find and fix the cracks should mount. These charts show mathematical trendlines over five years with positive and negative slopes. While fleet age and SDRs are rising, maintenance spending to find and fix structural cracks is going down.

THE AGE FACTOR: THE ‘BATHTUB’ CURVE

Among the most important factors in determining the structural integrity of the nation’s airlines is the age of the fleet, manufacturers agree. Advancing age makes planes more likely to crack. The average age of each of the six aircraft making up the bulk of the fleet has increased each year from 1980 to 1984--even taking into account the introduction of new planes. Both Boeing and McDonnell Douglas suggest that after a period of initial “shakedown” problems, planes should have few structural problems until they have been in service for a number of years. Both manufacturers suggest that there will be an increase--reflected by what the airline industry calls a “bathtub” curve--in the number of structural defects after that point.

AIRCRAFT OF THE FLEET These are mathematical trendlines with positive and negative slopes showing increases and decreases over five years. The first in each panel shows the increase in the average age of the type of aircraft. The second shows the decrease in Service Difficulty Reports (SDRs) on structural cracks. The third shows the decreases in spending for structural maintenance.

AIRLINE INSPECTION EXTENSIONS

Airlines name maintenance inspections with letters “A” to “D,” with “A” checks being the least comprehensive and “D” the most comprehensive.

As the production time nears for a new type of aircraft, an FAA maintenance review board, with representatives from the agency, the manufacturer and the airlines, establishes intervals between these inspections--or “letter checks.”

Within months, however, airlines ask the FAA’s Principal Maintenance Inspectors (PMIs) assigned to their maintenance operations for extensions in the intervals. PMIs grant extensions when airlines convince them that they are warranted.

Here, according to a Boeing Co. document obtained by The Times, is a sample of extensions for 727s at three airlines as of November, 1985:

REPUBLIC AIRLINES Recommended Inspection Airline’s Maintenance Schedule schedule A check Every 105 flight hours 80 hours B check Every 730 flight hours 400 hours C check Every 3,300 flight hours 1,600 hours D check Performed in 10 phases, one during 16,000 hours each C check, but with total elapsed time not to exceed 30,000 flight hours

TWA Recommended Inspection Airline’s Maintenance Schedule Schedule A check Every 75 flight hours 80 hours B check Every 600 flight hours 400 hours C check Performed in two 1,100-hour phases, 1,600 hours total elapsed time not to exceed 2,100 hours D check Every 19,000 flight hours 16,000 hours

UNITED AIR LINES Recommended Inspection Airline’s Maintenance Schedule Schedule A check Every 200 flight hours 80 hours B check Every 550 flight hours 400 hours C check Every 13 months regardless of flight hours 1,600 hours D check Every 48 months regardless of flight hours 16,000 hours

A LOOK AT THE U.S. AIR FLEET

REVENUE PASSENGER MILES (in thousands)

One measure of growth in the airline industry is by revenue passenger mile, or RPM. It represents the number of paying passengers who fly one mile.

1980 1981 1982 1983 1984 255,192,114 248,887,801 259,643,870 281,829,148 304,458,727

Source: Air Transport Assn.

FLEET SIZE

1974 1983 1984 2,511 3,585 4,223

MAINTENANCE WORKERS EMPLOYED

1974 1983 1984 46,589 40,359 42,558

Source: Air Transport Assn .

FEDERAL INSPECTORS

1979 1982 1984 2,012 1,735 1,332

AIRLINE CARRIERS

1979 1982 1984 237 389 407

Source: Air Line Pilots Assn.