An investigation into a crash that killed an Embry Riddle-Aeronautical University student and his flight instructor has found that another plane at the university had a crack in a bolt attachment within its wing, according to a federal aviation investigation.
The National Transportation Safety Board issued a report this week that showed when inspectors examined a second Piper PA-28 aircraft, they found a fatigue crack that was similar to cracks found in the left wing of an ERAU plane that crashed April 4 after its wing fell off in mid-air. That crash killed Zack Capra, a 25-year-old Navy veteran taking his commercial pilot license test, and Federal Aviation Administration pilot examiner John S. Azma, a father of four.
The NTSB report did not say that the second inspected plane was part of ERAU’s fleet. But a search of FAA records showed the plane is registered to the university.
Investigators also examined nine planes of the same model and “similar vintage” from two flight schools in Florida and one in Texas. Evidence of cracks were not found in them, the report stated.
Embry-Riddle spokesman James Roddey said that the "NTSB investigation is ongoing, and as such, we have nothing to add to the recent investigative update."
The school's fleet of about a half dozen Piper PA-28 aircraft remains grounded, and it's not clear whether they will ever be flown again.
According to the report, the second plane’s wings were removed, and an inspection of its left wing spar, a metal structure that bears the load of the wing, revealed a “crack indication” at an attachment bolt hole. The plane in the deadly crash was also found to have fatigue cracks in its left wing beginning “at or near an attachment bolt hole.” Investigators said that plane was climbing when the wing separated from the fuselage, causing it to spin out of control and then slam into a cow pasture along Tomoka Farms Road near the Daytona Flea & Farmers Market. It had performed a "touch-and-go landing" at Daytona Beach International Airport just prior to the crash, investigators said.
Both of the inspected planes had accumulated just over 7,600 hours of flight time and flown more than 32,000 cycles — counted as one takeoff and one landing. The single-engine planes, better known as Arrows, were both manufactured by Piper in 2007.
Piper Aircraft spokeswoman Jacqueline Carlon said in an email statement that it “continues to support all the investigative efforts by the NTSB.” ERAU and FAA officials are also part of the investigation, according to the report.
Mike Busch, a California-based maintenance expert who is often called upon in aircraft litigation, explained that the crack that was found in the bolt hole attachment of the second plane’s wing spar was microscopic in length and depth, and that it “couldn’t be detected visually.”
An eddy-current inspection, a test that uses electromagnetic induction to uncover subsurface flaws in metal, was performed by Piper representatives to detect the cracking.
“The expectation is that (the crack) will propagate overtime,” he said. “But it’s still an open question of what is required for that type of cracking to occur.”
The plane in the deadly crash was used exclusively in flight training, and it had received its annual inspection on March 21, just two weeks before the crash, flying some 28 hours afterwards, the initial report said. The latest report does not say whether the second plane was used exclusively in flight training.
But investigators went on to examine planes at two separate Florida flight schools, including one with two planes that had similar “operational backgrounds” as ERAU’s planes. At the other flight school, inspectors tested five retired planes, with each one reporting between 8,600 and 10,300 hours of flight time and an estimated 30,000 cycles, though the cycles were not specifically tracked, the report said. Two planes, which had about half the flight time and cycles, were also examined at a Texas flight school.
Under the supervision of NTSB officials and others, the same bolt holes on all the planes were inspected using the eddy-current test. “No crack indications were detected,” the report said.
Busch said the probe into the other planes is attempting to determine whether the cracks were the result from flight time and patterns unique to flight schools — or even to ERAU’s Piper fleet. The Piper PA-28 has retractable landing gear making it suitable for advanced students looking to obtain their commercial license. Roddey said that recent FAA rule changes regarding what is considered a complex plane, such as the Piper PA-28, has allowed the school to streamline its flight operations.
“There probably aren’t a lot of planes that get such intensive activity as the ones at Embry-Riddle,” Busch said. “It’s a very busy flight school.”
According to the report, the investigation is also looking at an airworthiness directive ordered after a Piper PA-28 crash with “in-flight wing separation.” That crash in 1987 caused the NTSB to issue an emergency order, requiring all of those model planes with more than 5,000 hours of flight time to have their wings removed and inspected. The order was eventually rescinded.
“That plane was subjected to a lot more low level air-turbulence than a normal plane,” Busch said. “They decided that was an overreaction."
Busch said that the NTSB is looking to narrow down what planes are at risk before possibly issuing an airworthiness directive this time that would require all Piper PA-28 planes be inspected by eddy-current — a test that is costly and difficult because there are few trained in the technique.
But, he said, the latest report is another indication that there “seems to be a problem.”
“I think they want confirmation with more airplanes before they decide what type of airworthiness directive to generate,” he said. “They want to get a better idea of what airplanes are likely to be susceptible to cracking.The hope is that they can narrow down the population of at-risk planes before deciding what remedial action to take.”