Hush Job

Cory Rasmussen

Editor's Note:

For years, public clamor over noise at the Minneapolis/St. Paul Airport has been nearly as deafening as the roar of a departing jet. Now there are indications that a technological fix to the problem--use of federally approved kits to "hush" the noise of DC-9 engines--may be a problem itself. An investigation by the alternative weekly Nashville Scene (excerpted below) has found that a consultant for the sole manufacturer of the DC-9 hush kits reports that faulty construction and installation may make the kits a dangerous hazard. The biggest user of the kits? Eagan-based Northwest Airlines, which uses 83 on their fleet of 179 DC-9s.

Last summer, aviation consultant Peter M. Friedman was hired to inspect parts being installed on DC-9 airplanes at a Trans World Airlines maintenance facility in Kansas City, Missouri. Friedman's specific objective was to perform a routine audit of the airplane's "hush kits," the devices used to muffle engine noise. The kits had been designed and sold by ABS Partnership, a low-profile, privately held company based in Sparks, Nevada. It was ABS that had hired Friedman to make certain the hush kits were of top quality and were being installed properly.

Friedman's credentials indicated he was the right man for the job. The Federal Aviation Administration (FAA) has designated him one of its "manufacturing inspection representatives," and he is certified by the American Society for Quality Control as a "quality auditor." In some sectors of the aviation industry, Friedman has a reputation as a relentless safety hound. Sometimes his critics describe him as a stickler for technical violations. But no one seems to doubt his knowledge of aviation-safety issues.

ABS had hired Friedman on a "confidential basis," meaning that he could only divulge his findings to the company. Nevertheless, his reports, copies of which have been obtained by the Nashville Scene, were so explosive, and his safety concerns so troubling, that they created a storm of controversy in aviation-safety circles.

Jim Frisbee, who was manager of quality assurance at Northwest Airlines until 1992 and who now works as an international aviation consultant, reviewed the Friedman report at the Scene's request. He says it raises "serious safety problems. Depending on the circumstances, the FAA may well have to ground these planes."

For airline passengers, Friedman's report is chilling. The document warns of numerous problems that could arise from the hush kits and "affect safety of flight" for the DC-9, one of the most common models flown by commercial airlines (U.S. airlines own almost 600 DC-9s, and it is estimated that at least one-third of them are flying with ABS hush kits). The report recommends that ABS take corrective action before a "catastrophic incident" occurs.

Specifically, Friedman's audit says the hush kit sold by ABS simply does not fit properly onto the back of the Pratt & Whitney engine that powers the DC-9. What's more, the report says, engineers and mechanics for each airline must figure out how to attach the kit's parts without the benefit of proper plans or workable instruction manuals. That state of affairs, which is in blatant violation of FAA regulations, increases the likelihood that mechanics will make mistakes when installing the hush kits.

If there is a bad fit, Friedman's report warns, the doors encasing the engine's tailpipe could blow open in midflight. That would be bad news for the DC-9, which typically cruises at speeds around 500 miles per hour. If the doors were ripped open, one of the plane's engines would continue to thrust the plane forward, while the other engine would do just the opposite. In that eventuality, the DC-9 could roll over onto its back, corkscrew down, and crash.

There's another terrifying scenario. If not fitted properly, one of the tailpipe doors could fly free and knock off the plane's tail, which sits just behind the two engines. If that happened in midflight, aviation-safety experts say, a crash would be virtually inevitable.

Friedman's report on the ABS hush kits also warns of mislabeled and obsolete parts, incomplete data, and miscalibrated equipment. It also charges that airline personnel have received "absolutely no" training in inspecting the hush kits before they are installed. The report warns that flight safety may be compromised by "cracked links and hinges," as well as by inadequate installation instructions. Friedman's report also notes that he inspected the ABS door assemblies that encase the engine's tailpipe, and found "each one [was] different from the next." Under the terms of his confidentiality agreement, Friedman declined all comment about his dealings with ABS.

ABS, however, says there is no problem with the kits. In February 1997 a company spokesman told the Scene that it was aware of no "safety of flight" hazards stemming from its hush kits. At that time the firm had already been in possession of Friedman's audit report for five months. In a later letter to the Scene, ABS says the firm is "absolutely certain" of the hush kits' safety. In the same letter, the company says it has been "open and cooperative with the FAA, the DOT, our customers, and the media. We are proud of our product, its in-service record, the professionalism, dedication, and diligence of the team we have in place to support our product and comply with all regulatory requirements."  

Following publication of the Scene's article, ABS also issued a fact sheet claiming that, contrary to Friedman's findings, it offers FAA-approved installation manuals and other technical assistance to airlines. The document also claims that "most of [Friedman's] allegations are beyond his field of technical competence."

Hush kits are installed because airplanes make a lot of noise, especially during takeoff and landing, annoying residents near airports like Minneapolis/St. Paul. At the height of the local noise controversy 10 years ago, Northwest Airlines threatened to pull out of Minnesota, claiming imposition of stricter noise rules would be economically damaging to it because its fleet contains a large number of older, noisier jets. A similar tactic was used in 1990 when Northwest stated it would build a new maintenance facility elsewhere if restrictions were enacted. At the same time, the airline exhorted employees to fight anti-noise activists by claiming noise reduction equalled job losses.

The controversy was ultimately muted, if not solved, by the issuance of federal noise regulations in 1991 under which all airlines would have to get rid of the noisier planes, or fit them with "Stage 3" hush kits--for which ABS is the only supplier--by 2003. According to Northwest's 1996 annual report to the Securities and Exchange Commission, the company plans to install the kits on 173 of its DC-9s. Eighty-three of the airline's planes already have the kits, making Northwest the leading user of the equipment. Airborne Express is second with 44 hush kit-equipped DC-9s.

Northwest spokesman Jon Austin says the airline is confident in the hush kits and the DC-9 fleet as a whole. According to Austin, Northwest has not received a copy of the Friedman report and is not aware of any investigation into the hush kits by the FAA or any other carriers in the industry. "When our planes go out they're ready to fly," Austin says.

Austin may not have heard of an FAA investigation, but federal authorities have been probing the hush-kit issue for some time now. The FAA acknowledges that it has opened two separate investigations of ABS for "apparent failure to conduct proper inspections at their supplier" and the possibility that counterfeit and unapproved parts were used in the hush kit. But it appears that the FAA may be showing interest in the hush-kit issue because another federal watchdog pressured it into doing so. A source familiar with the case says the FAA obtained Friedman's report only because investigators with the U.S. Department of Transportation's Office of the Inspector General had suspicions ABS was not giving straight answers.

Having reviewed the Friedman report, however, the FAA maintains it is not worried. Ronald T. Wojnar, manager of the FAA's Transport Airplane Directorate, told the Scene there was "no material of any major significance to the FAA" in the document. And James V. Devany, manager of the FAA's Manufacturing Inspection Office for the Transport Airplane Directorate in Renton, Washington, says the FAA does not have "an airworthiness problem" with ABS's hush kit.

Aviation-safety experts who have seen Friedman's report are shocked at Devany's statement, and at the fact that the FAA has not shown the document to the airlines. "This is a total disaster. It's intolerable," charges Frisbee. "If I had seen this report when I was at Northwest, I'd have taken immediate action." And even Devany's colleagues at the FAA find his analysis suspect. "There appears to be a real safety-of-flight problem with the hush kit," says an FAA flight-safety inspector who has reviewed Friedman's report and requested anonymity. "It looks like some FAA officials have taken a cover-your-ass mentality, instead of fixing the problem."

As industry insiders scratch their heads about the FAA's reaction, some charge the response is typical. In her recent best-selling book about the FAA, Flying Blind, Flying Safe, former Inspector General of the U.S. Department of Transportation Mary Schiavo charges that the FAA's entrenched bureaucracy seldom takes action until after a disaster has occurred. "The FAA would rather hide an aviation-safety problem than fix it," she told the Scene. "The FAA doesn't act on a problem until after a crash, or more likely, after two crashes. That's what we call the 'two-crash rule.' They hush up safety problems because it costs a lot to fix them and because it's very embarrassing to the FAA."  

Frisbee concurs. "If the FAA acknowledges that the DC-9's hush kit isn't safe, it would be a highly embarrassing admission that the FAA may have made serious mistakes--first in approving ABS's hush kit for use, and second for not exercising proper oversight of the manufacturing process to ensure the hush kits were built properly."

George Breckel, a veteran aircraft mechanic who has inspected the type of Pratt & Whitney engines to which the hush kit is attached--and who now coordinates the aircraft mechanics' training program at Vincennes University in Vincennes, Indiana--is more succinct. "I'd say somebody, or [some]bodies, is covering their ass," he told the Scene after reviewing the Friedman report.

Since this article first appeared in the Scene, U.S. Reps. Peter DeFazio, D-Oregon, and William Lipinski, D-Illinois, have requested a hearing on the hush-kit issue in the House Transportation Committee's Subcommittee on Aviation. Lipinski is the ranking Democrat on the subcommittee, while the ranking Democrat on the Transportation Committee is Minnesota's Jim Oberstar; a spokesman says Oberstar so far has "not been personally involved" in the matter. "From what we're hearing there's not much of a story there," says Jim Berard, the Democratic communication director for the House Transportation Committee. "The FAA has looked into the situation, and they are at least satisfied in their preliminary findings that these concerns are unfounded." Berard says any hearing on the matter will not be scheduled until next year.

The airlines, meanwhile, have taken their own steps to deal with potential problems with the ABS hush kit. John Williams, director of material management and component shops for Northwest Airlines in Atlanta, called a meeting of air carriers on September 24, 1996, to "discuss DC-9 hush-kit issues." Williams's invitation letter indicates that the meeting was to be held at TWA's Kansas City facility and that the participants were to include representatives of several carriers, including TWA and US Airways. Apparently, the FAA was not invited. Williams did not return repeated calls from the Scene.

But other airline officials who attended the meeting say there was lengthy discussion of the problems with the ABS hush kit, including the fact that it simply did not fit correctly. According to aviation-industry sources, the FAA was not invited because the airline officials did not want to alert the federal agency to the problems.

One reason the airlines would prefer to keep the problem secret may be money. An airline loses an estimated $19,000-$21,000 a day for every DC-9 that's taken out of service, according to the Canaan Group, an aviation consulting firm based in Park City, Utah. If the planes were to be grounded by the FAA to fix or replace the hush kits, the airlines would almost certainly forgo significant revenue.

For Northwest, the economic stakes are particularly high. Installing hush kits allows the company to extend the life of its large fleet of older DC-9s into the next century. According to the airline's SEC report, "Although the DC-9 and DC-10 average aircraft age exceeds 20 years, these aircraft have considerable remaining technological life. The Company estimates these aircraft could fly on average approximately 16 years beyond 1996."

Questions about the hush kits should only be taken seriously, of course, if Friedman's report turns out to be accurate and fair, and if his own credibility is not challenged. It is worth noting that Friedman has a potential conflict of interest in connection with the hush-kit issue. His employer, Airweld Inc., already has a contract to overhaul and repair certain DC-9 parts for the U.S. military--the very same parts of the engine to which the ABS hush kit is attached. Though Airweld has no history of making hush kits, if ABS were knocked out of the hush-kit business, Airweld and dozens of other aviation firms might look into entering the market. Still, ABS was fully aware that Friedman worked for Airweld before he was tapped to do the audit report.

"Even if half of what Friedman says is true," warns Breckel, "you've still got a serious problem." Thomas Cruse, a professor of mechanical engineering at Vanderbilt University and an expert in large-aircraft engine structures says Friedman's technical knowledge "appears first-rate." While Cruse cautions that he would need more technical information to make a final determination on the DC-9's safety, he says the FAA can't be "confident" at this point that there are no safety concerns.

Frisbee, for his part, isn't willing to wait. According to Frisbee, "Friedman did a good audit. If [the FAA's Devany] says there's no problem, then I'd like to tell him to put his wife and kids on one of those planes. Then wait and see what happens."  

Willy Stern, a former staff writer at Business Week and Forbes, has broken numerous stories in the national media about the aviation industry. City Pages News Intern James Bryant MacTavish contributed to this article.

Sponsor Content


All-access pass to the top stories, events and offers around town.

  • Top Stories


All-access pass to top stories, events and offers around town.

Sign Up >

No Thanks!

Remind Me Later >