European Stars And Stripes (Newspaper) - December 31, 1988, Darmstadt, Hesse                                Magazine America s aging jets new York times a aviation safety experts and Federal regulators say belter  must to developed Lor America saying Ai Ilmer Heel if the planes arc still there is growing concern about providing the special maintenance an older plane requires. For example Matulac tuners and the airlines Ere discovering that properly maintaining an older plane can be substantially different from caring for a newer one. In Many cases the detailed nature of a maintenance program has to be re Houghl. And while that process is under Way i is far from Complete there is also growing concern among safety experts hat too Little attention is being paid to  of the mechanics who maintain older planes and whether they have adequate equipment and follow carefully thought out procedures ,.the safety experts concede that finding cracks and corrosion in plane frames and skins is Ollen Boring work that is subject to human error. In some cases the mechanics May not be fully trained in selecting such problems or May Lack up to Date equipment in others rapid turnover among mechanics at airlines aggravates the problem there is also concern thai the Federal aviation administration which has responsibility Lor overseeing the maintenance has in recent years put Loo much emphasis on the paperwork associated Wilh maintenance rather than actually checking Ine repair work we Aro very concerned about what to Call inc human Factor in maintenance and we Are just now focusing our attention and coming to a widespread awareness of the  said Clyde r. Kizer vice president Lor maintenance and engineering at the air transport association the Industry Irene group that has been Given a Lead role in assessing the. Maintenance problems of the nation s airliners and defining How to Deal with them. The advancing age it America s air Heel had been of increasing concern to airline executives end aviation safety experts Well before the Aloha incident. But the latter was so dramatic that it became a galvanizing Force. After the incident immediate visual inspections of Boeing 737 s were ordered. Then in october a 12-Inch crack and several smaller cracks were found in a Continental airlines 737 when paint was stripped As part of routine repainting. The cracks had not been detected in the visual inspection in May an Continental officials said they could have developed after the Check ". The f a has proposed that some 7.000 rivets be replaced on each of More than 100 older 737 s. The Cost of such work is estimated at $600,000 to $700,00 per plane. Despite the Aloha and Eastern incidents air plane manufacturers say that aging planes can remain in  without compromising safety if they Ere properly maintained. There is no question that As air planes gel older the maintenance problems go  said  director of structures engineering Lor the Boeing commercial air plane co. I Don t eel we Are. Compromising safely in what we Are doing. These kinds of things have been happening Over the years and the Public has t taken  moreover Boeing officials Point out that their continuing studies of airline accidents worldwide show that structural problems cause Only 3 percent of the accidents. The vast majority Are caused by Pilot errors the studies show the aviation experts agree Hal learning How to maintain older planes is turning out to be uncharted territory.   we  past. Experience said Jean Mcgrew director of aircraft design engineering at Douglas aircraft co. In Long Beach Calif. I would t say that anything is unsafe but if you Are too Sloppy or Loo complacent with respect to aging air Rall. Things could  in some cases recent incidents have caused airlines to immediately alter some maintenance procedures for older air Rall while Ether changes have evolved Over time. Doha air lines and United Anil Mes began inspections Altheir older 727 s after shia week s Eastern incident. James m. Guyotte executive vice president for operations Al United said All 72 of the company s 727 s similar to the Eastern plane would have been inspected by Friday morning. Gayelle said Hal As pah of United s evolving maintenance program for older pianos the annual inspection or a Check in which the plane is heavily worked Over has grown from 15 Days a few years ago to 25 Days. As we learn More about these air planes and their age. We will work even More things info the 0 Check he said. Defining How Many airliners should be of concern is diff cull a plane s age can be measured in total hours of flight Lime years in service or number of flights Boeing Lor example said that 1.649 of ils 727 s Are in service around the world and that 435 of them Are More than 20 years old and 358 of them have More than 50.000 hours of lying time. It said 170 planes have made More than 43,000 lights. -.-, Boeing issues design objectives Lor. Each of its Type of plane. For the 727, Lar example the company says a plane was designed to be used Lor Only 60.000 flights or 50,000 hours or 20  plane in the Aloha incident had Maden Earty. 90.000 nights. "  r " the concern with older planes is fatigue and corrosion in the Metal ribs or frames and the horizontal. Stringers that run from rib to rib. Aluminium skin which is glued and riveted to this Structure to lorm the  also Baa problem. .".--. Silica by Ribera Fly at High altitudes where there is not enough oxygen for passengers to breathe the Interior of the Craft is pressurized at about 5,000 feel above sea level. Each Elmea plane takes off climbs to ils prescribed Altitude and then descends to a Landing. The null bulges slightly from pressurization and then relaxes. These cycles along with the stress of Landing and turbulence in the air Lead to a fatiguing of the ribs and stringers and a Strain on the skin rivets and glue. Weathering operation in a Salty Ocean environment and leakage of corrosive substances can cause corrosion of the beams or the  fatigue or corrosion go undetected a rib can ail or a Point where two pieces of skin overlap can develop a leak or even blow open suddenly As apparently happened with the Eastern 727./ when manufacturers airlines and the Faa Lirosi developed the detailed maintenance plans for planes it was nol expected thai the planes would be in use pm As Many years As they have been. As a result there was no provision for the detailed inspections that. Engineers now realize Are necessary to Lind fatigue and corrosion of structural elements deep inside a plane deciding in new maintenance procedures and How to put them into practice is the current Issue. Saturday december 31,1988 the stars and stripes Pago 13