FIVE DAYS TO FLIGHT TIME

[Music] this dc-8 is landing at san francisco's huge international airport in the past month it's been to boston seattle new york denver and chicago we'll find out more about the excitement of keeping these huge airplanes flying today when discovery takes a first-hand look at five days to flight time [Music] discovery 70 the award-winning program for young people with bill owen and virginia gibson this is san francisco's busy international airport planes from hong kong australia london tokyo honolulu and new york land here every day and take off on their way to other parts of the world [Music] but in order to keep flying in order to meet their busy schedules every six to eight thousand hours they stay over for five very active days at an important building here in the backyard of the airport hi and welcome to discovery this is doc3 one of the huge overhaul hangers here at the united airlines maintenance base in there's a dc-8 one of the big four engine jets each plane has its own number that one's 2601 and it's here for its sixth overhaul or as they say here it's sixth visit and last night this was the scene as it came into dock 3 for the start of one of the most complete examining and testing procedures possible for an aircraft it's a delicate procedure and has to go slowly there are watchers on both wings the men now in the cockpit are mechanics the tug hauling it will line up on that all-important white line down the center that whistle is the signal for all to stop as something is checked it's a pretty tight fit since the dc-8 is 148 feet wide on each side there's about six feet of clearance this airplane is more than 150 feet long and about 43 feet high the tail section that's the rudder which the pilot uses in making turns it's 24 and a half feet high and weighs 722 pounds the largest control surface on the plane the first shift last night was responsible for what they call unbuttoning the aircraft making it ready to be worked on this is a first inspection looking to see what will have to be done all screws or bolts or as they're called here fasteners are put in small cloth bags and hung at their location they won't be used again but when it comes time to close up the plane five days later it's an efficient way of identifying exactly what new fastener and what length is needed for each spot during the five days all the paint will be removed and to do this areas that might be affected by the strong solvents are masked many areas have to be cleaned before they can be worked on each kind of work is important to the job that follows it this shift is readying the plane for the midnight crew that is about to arrive number 2601 has just landed on a non-stop flight from new york and still has some fuel in its tanks which has to be removed while 2601 is here in the dock it will be supported by three hydraulic jacks these jacks must support 350 000 pounds one under the nose and one under each wing he'll raise the plane two more feet so that the landing gear can be worked [Music] on in each visit more than 1 415 mandates are needed to do a complete overhaul which calls for moving fast and for careful coordination among all the mechanics one important element is making the aircraft as safe as possible to work on this is a break which will keep these landing gear well doors open these red tags reading remove before flight are always placed on any piece of maintenance equipment used in the overhaul to work around a plane as huge as the dc-8 you need a scaffolding just as you would if you were working on a five-story building these are specially built for the dc-8 and fit all around it and to get in close the flop boards drop into place [Music] the scaffolding permits the mechanics to work at several different levels at the same time the wings each have their own huge slanted stands the stands are motorized to move into place any surface other than a control surface that can be removed from an aircraft is called cowling and covers areas that need regular attention or inspection the fixed covering of aircraft is called skin and in the visit such as we're seeing that skin will get plenty of cleaning and polishing any piece of equipment or part of the plane that carries this aog label standing for aircraft on ground has top priority everyone knows 2601 is here for just five days and unless some major repair is needed that will keep it on the ground longer it will be ready for its test flight by friday midnight everyone here knows and feels the importance of the five-day working schedule for this plane 2601 is expected back in the flying schedule on a non-stop flight to new york on sunday so when the 11 o'clock crew comes in on sunday night one of the first jobs is getting the rudder off since it weighs 722 pounds the weight has to be supported in a sling then working through access holes fasteners are removed and eye bolts removed at the bottom it's detached from the large control wheel that bears most of the weight and moves the rudder it's finally ready to be lowered to the dark floor [Music] loaded on a dolly and rolled off to the sheet metal department to be thoroughly examined and repaired if necessary repainted and rebalanced a very important procedure that we'll see later the cabin gets plenty of attention during an overhaul the seats are taken out to be completely redone but even if that weren't necessary they would have to be removed so that the crew that works on the cabin could inspect and work on the important airframe that is the skeleton of the aircraft this inspection is the most important one for an aircraft while it's in regular service it's inspected every day and there are 50 100 and 250 hour inspections as well this big one the one that comes every six to eight thousand hours is also used to modify or update the aircraft when number 2601 was purchased it cost about four million dollars now later with modifications and improvements and allowing for what would cost to replace it it's worth just about twice as much a good many of the improvements are inside the cabin and if you'd like to see what the inside of a dc-8 looks like when it's stripped down we'll do that in just a minute [Music] we're two days into our number 2601 overhaul and there's just as much going on inside the cabin as there is outside the galley or kitchen is hardly recognizable now all the equipment has been taken out with the covering removed we can see the thick insulation that helps to sound proof the cabin here are the light connections there will be new carpeting enough to carpet two average homes these are the control cables that come back from the cockpit going through the floor beam support web on the way to the rudder at the back of the plane anytime a mechanic finds a better way of doing a regular job on an overhaul it's passed on to engineering for an okay each job is supervised in process by lead men and finally accepted by a government licensed inspector uh none of this complicated work can be kept track of if it weren't for the planning office it's always the scene of great activity when the shifts change overhaul is first programmed for about 1400 routine inspections and checks and minor repairs the standard jobs are represented by these white slips and they're as many as 1500 items represented by the yellow slips that come to light in the first day or so of the overhaul these are called non-routine and once programmed into the overhaul they too must be completed in the five days when a job is finished it's signed for as completed then the slip is removed from the board every single piece of paper is accounted for as an extra check [Music] this is the rudder of number 2601 all the plain surfaces are subject to great stress and wear while in flight the first part of any surface the part that's in the front is called the leading edge and it gets special attention after the leading edge is removed the ribs and fasteners are checked after the rudder is inspected and painted it will have to be rebalanced since the rudder must respond quickly to a change in direction balance is extremely important these weights fasten to the leading edge are part of that balance and they may have to be changed even the weight of the two gallons of paint on the rudder has to be taken into account the rudder is fastened to two balance stands and a protractor level is placed on it the trailing edge should come to this indicator pieces of metal are hung on it to bring the rudder into balance the same amount of weight is now added to the leading edge and the rudder is in perfect balance [Music] the wingspan of a dc-8 is 142 feet and almost every inch of it has a function the most important one of course is to keep the aircraft flying then to all the fuel tanks are in the wings and they're an integral part of the wing structure there's a special way to examine the wings and we'll see how that's done in just a minute with all of the activity needed to complete a major overhaul it's a good idea to have some traffic signals to keep things going smoothly this flashing red light tells us that some movable control is being tested and to watch out for it here we see the flaps being tested this is a portion of the wing that comes down in landing and puts extra drag on the plane to slow it down their movement will be checked through the full range needed to stop the aircraft the lights at the end of the wing are called navigation lights and are also important when the plane is being moved on the ground these are the ailerons the control surface on the wings that coordinate with the action of the rudder to give a smooth turn these are called static wicks are used to get rid of the static electricity that builds up in an aircraft in pioneer aircraft they were actually made from candlewick fabric everyone who walks on the wings must wear these protective socks called booties the wing surface is strong but it can show scratches using a gamma ray projector a radiograph is made of the jet engines the gamma ray works on the same principle as an x-ray but it's able to penetrate thicker materials like the heavy metal engines of the dc-8 the sharp corners on the wing surfaces are covered with protective corners for the mechanics safety this section set in the flap is a flat gate and as the flap goes down it goes up this is where there's a strong blast from the jet engines and the flat gate lets it pass instead of having it batter the flap the fuel tanks and the wings hold all the jet fuel needed for a flight more than 22 000 gallons the inboard tanks are inspected from inside it's a special job for men who aren't too big and for the tanks farther out too small for a man to get inside inspection is done from the outside [Music] as we've moved along the wing we've been going from the outboard to the inboard position on the plane those are terms that like many others come from ships another nautical term of course is rudder actually this isn't the same rudder we saw being removed there's always one ahead in the sheet metal shop ready to be put on almost immediately to save time in these five days [Music] since the balance is so important the final element is the trim tab an eight inch strip of metal on the rudder that can be bent one way or another it's so delicate that the angle of the previous tab is noted to be duplicated in its replacement while inspection goes on all the time starting with when the plane is unbuttoned right straight through the five days as we get closer to friday midnight and more jobs are finished the pace of the inspection increases and each job has to be signed for by the man who works it as well as the inspector who okays it there's inspection in the cabin too even the upholstery the fit of the carpet everything has to check out late friday night when the stands are pulled back and the towers rolled away there's one more inspection in the dock it's called a walk-around and it's a final eye check there's still one final and very important check the test flight rdc8 number 2601 is ready to go for the past five days it's been aog aircraft on ground in a tight schedule every minute counts every man counts the crew in dock 3 will give the same care and attention next week to another dc-8 they'll have the same tight schedule but a few small things will be different each plane is very special and not quite like any other we'll be back in just a minute at this time tomorrow number 2601 will be in new york the next day it may be in los angeles or honolulu or even back here in san francisco able to go anywhere because of the work that was done at the huge maintenance base if you'd like to find out more about the excitement of air travel and airplanes ask your librarian for any of these books cleared for takeoff by charles coombs what does an airline crew do by eroy ray and this book behind the scenes at an airport by david c cook be sure to be with us next week as discovery continues to discover the world bye bye bye the discovery production units domestic transportation and promotional consideration provided by united airlines [Music] this has been the jewels power production in association with abc news