luckily, no passengers onboard. delta air lineses saying mechanics were testing the engines when they suddenly had a problem with the brakes. peter gold is former managing director of the national transportation safety board, a man who has looked a many accidents more serious than this one. peter, how do you test the engines without brakes? well, there are processes and procedures. mechanics move aircraft around airports like atlanta every day, and there s a couple of things you ve got to do. one is you ve got to make sure that the hydraulics system is charged, that the pumps are on. that gives you the braking power. the second thing is if procedure calls for a static runup of the engine, then you ve got to make sure you have your blocks in place to make sure the wheels aren t moving. i mean, this is, this is an awfully tough way to start the day if you re delta air lines. jon: yeah. the checklist, when i fly a little single-engine plane, the
the structure is so large, more than 15 feet across, the airplane was built around it. to make the fix, boeing removes the skin of the airplane, replaced the bulkhead s damaged lower half and replaces the skin over it. to fuse the halves it calls for a splice plate or doubler. but with the skin back on the doubler doesn t fit. the boeing field reps make the call to cut the piece in half. that s problem number one. problem number two the correct procedure calls for two rows of rivets to hold the doubler in place. only one row is used. for seven years the single row and the split up panel have been carrying twice the load they should have been. they decide to alter the installation procedure. it wasn t an approved procedure. the repair is certified to
to make the fix, boeing removes the skin of the airplane around the bulkhead. replace it is bulkhead s damaged lower half and reinstall it is skin over it. now the trouble, diffuse the two bulkhead halves boeing calls for a zblg sflis tape or doubler. with the skin of the plane back on, the doubler does not fit. boeing field reps make the call to cut the piece in half. that s problem number one. problem number two, the correct procedure calls for two rows of rivets to hold the doubler in place. only one row is used. for seven years, the single row and the split-up panel have been carrying twice the load they should have been. they decided to alter the installation procedure and it wasn t an approved procedure. reporter: repair is certified to last 10,000 takeoff land
splice. but with the skin back on, it doesn t fit. field reps make the call to cut the piece in half. that s problem number one. problem number two, the correct procedure calls for two rows of rivets to hold that doubler in place. only one row is used. for seven years, the single row and the panel have been carrying twice the load they should have been. they decided to altar the installation procedure. it wasn t an approved procedure. the repair is certified to last 10,000 takeoff landing cycles. by the day of the crash, this particular 747 has already gone more than 12,000 cycles. the repair is inspected, but because a sealant has been used, cracks developing are not found. this plane is a ticking time bomb. unfortunately, the repair was insufficient and cracks started
around it. to make the fix, boeing removes the skin of the airplane around the bulk head, replaces the bullhe bullhead s damaged half and then replaces the skin over it. now the trouble, to fuse the havs it called for a single slice plate or double lure, and the doubler doesn t fit. they cut the piece in half. that s problem number one. problem number two, the correct procedure calls for two rose of rivets to hole the doubler in place, and only one row is placed on there. they decided to alter the installation procedure. it was not an approved procedure. the repair is certificated to