A380 completes wing static test

The Airbus A380 was put through a static wing load test at the Airbus static test facility in Toulouse, France. One of the A380's wings snapped between the inbound and outbound engines at an applied pressure of about 96.67 percent of the ultimate load. Airbus vice president for engineering, Alain Garcia, felt the wing test had been a success since the rupture occurred "within 3 percent of the target." Garcia also predicted that the wing's failure will require "essentially no modifications" to production aircraft. Chief officer John Leahy recently added that the wing failure was "not a big problem at all."The ultimate load has a built in safety factor of one-and-a-half times the limit load, which is the highest aerodynamic load expected during an aircraft's lifetime of normal service. When the same test was conducted on an Airbus A330 in 1992, the wing failed just below its target load just as the A380. As American Airlines Flight 587 took off from JFK on November 12, 2001, the tail of an A300-600R had snapped off. This tragedy killed 265 people, a small number compared to the potential 853 passengers on the A380.Although not subject to operationally realistic temperature and humidity conditions, the Airbus A300 had been fully tested to ultimate load, 1.5 times the estimated limit load. Unfortunately, Airbus had clearly underestimated even the limit loads for the A300.Last fall, FedEx maintenance workers found a three-foot section of the rudder had begun to break apart on one of its Airbus jets. This discovery comes after a nearly identical Airbus lost its rudder during a flight from Cuba to Canada in early 2005. The National Transportation Safety Board (NTSB) said that the rudders of many Airbus passenger jets are made of composite plastic that appears to be dangerously prone to disintegrating. The 2001 crash and a March 25 recommendation on safety posted by the NTSB raise questions about maximum capabilities, or "limit load," of many Airbus aircraft, said Robert Spragg, an aviation lawyer in the Manhattan firm, Kreindler and Kreindler. "If there are a number of events where the limit load is exceeded, that would draw into question Airbus Industries' initial calculations," Spragg said. In a recent Airbus safety drill in Hamburg, Germany, which tested how long it would take to evacuate a fully loaded A380 with half of the exits blocked, 32 volunteers suffered minor injuries, and one man broke his leg. Airbus manager Gustav Humber said, "That was a very great success."No American carriers have so far placed orders for any A380's

Full Scale Fatigue Testing of military aircrafts at NAL

Full Scale fatigue testing at NAL

After successful completion of the test programme of Gnat Fighter Aircraft using full scale fatigue test rig developed by NAL, the Structural integrity Group(SIG) has taken the major task of developing a computerised full scale fatigue test rig under the project of development of fatigue test facilities. This has felt necessary in view of the practical difficulties experienced during the use of the existing six actuator full scale fatigue test rig. Sufficient clear heights for rigging of loading trees was an important consideration in the design of the new test rig. The floor area of the test rig was arrived at by examining the plan form dimensions of number of fighter air-crafts in IAF. It was decided that the test rig should be designed as a "self reacting frame work in order to avoid heavy foundation work. Another requirement was that there should be enough free entry space so that air frames of most of the fighter aircrafts can be easily moved into the test rig. The facility has been conceived Initially as a 24 actuator system in which 16 actuators are assigned to the wings, 5 actuators to the fuselage and 3 actuators to the empennage. The system will be enlarged subsequently to include more number of actuators . The test rig itself has been designed for a maximum operational load of 50,000 lbs with the maximum structural deflection restricted to 20 mm at design load
The SIG has taken up several FSFT activities for life extension of fighter aircrafts .
The recent life extension studies was done for Mig-21 Bis aircraft for IAF and all the loads experienced by the aircraft in the sevice conditions are simulated on the ground to extend its life from 2400 hrs of flying which is the designed life of MIG 21and now IAF can heave a sigh of relief - the life of the MiG-21 Bis has been enhanced. The entire fleet of the MiG-21 Bis, tests by National Aerospace Laboratories (NAL) have revealed, can now fly an additional 1,000 hours or effectively for another 10 years.
With the entire MiG-21 Bis fleet of 150 aircraft approaching its maximum life-span of 2,400 hours as per original certification by Russia, IAF went for the life-enhancement test at NAL.
It flew in a MiG-2The results come after NAL's successful completion of full-scale fatigue testing (FSFT) on the MiG-21 Bis airframe C-2090. With this a major IAF project on the total technical life enhancement (TTLE) of the MiG-21 Bis fleet has come to an end.
the aircraft had completed 2,400 hours and had no fatigue cracks. The question before IAF was - how much longer could the aircraft fly? IAF requisitioned NAL to extend MiG-21 Bis life from 2,400 hours to 4,000 hours - an additional 1,600 hours. The aircraft, however, experienced cracks and break-up after around 1,000 hours of flying.
"There was no question of further testing as the aircraft had reached its limits. But it became evident that its life could be enhanced by 1,000 flying hours," said NAL official Dr.P K Dash.
Dash further said: "What loads the aircraft experiences in flight in a whole year, we simulate on the ground in one day, checking for fatigue.
When fatigue shows up, you know that is the point up to which the aircraft can fly."The key issue in preserving structural integrity against fatigue failure, Dash said, was to get precise answers to where and when fatigue cracks would appeared in the airframe, which, if undetected in time could lead to catastrophic structural failure.

Airbus a380 wing Static testing

Airbus is downplaying test results in which an A380 wing undergoing static testing failed slightly before the required design limit.
The wings are supposed to take 1.5 times the design load limit but this one failed at 1.45 times, about 3.3 percent shy of the certification requirement.
Airbus spokeswoman Barbara Kracht said the wing will need some “refinements” but the aircraft is on schedule for certification and first deliveries late this year. “We will need to find out from the data what is really needed but it’s certainly not a redesign of the wing,” Kracht told Associated Press.
In order for an aircraft to be certified here in the U.S., it must withstand the maximum “g” loading specified for that category, plus a 50% overload factor. For example, in the Normal category, the aircraft must withstand a positive load of 3.8g and a negative load of -1.52g at maximum gross weight. It must also be able to withstand an additional 50% of those loads without failing.
These “static” tests, as they’re called, are accomplished on the ground by mechanically loading up the wings. Sometimes this is done by simply placing sandbags on the wings to simulate a load. Large manufacturers like Boeing and Airbus use slightly more expensive methods. I’ve seen video of a 777 wing being tested to failure — the wings bent up to the point where they almost touched. In other words, it handled far more than the required loading.
The requirements for the Transport category are set out in 14 CFR 25.337(b)-(d):
(b) The positive limit maneuvering load factor n for any speed up to Vn may not be less than 2.1+24,000/ (W +10,000) except that n may not be less than 2.5 and need not be greater than 3.8 — where W is the design maximum takeoff weight.
(c) The negative limit maneuvering load factor –
(1) May not be less than −1.0 at speeds up to VC; and
(2) Must vary linearly with speed from the value at VC to zero at VD.
(d) Maneuvering load factors lower than those specified in this section may be used if the airplane has design features that make it impossible to exceed these values in flight.
So if the plane is going to be certified in the Transport category, it will have to handle somewhere between 2.5 and 3.8 positive G — plus 50% — depending on the maximum takeoff weight.
I’ve never heard of an aircraft failing to withstand the 1.5x test. That’s not to say it’s never happened, just that I’m not familar with such an ocurrance.
However you slice it, this has got to be a huge embarrassment for Airbus. Even if the flaw was simply a construction defect in the prototype, it will bring into question every other aspect of the A380’s design and construction in the minds of potential customers, not to mention the flying public.