By JOSH FUNK AP Transportation Writer
Investigators are just beginning the lengthy process of determining why a business jet plummeted from the sky in Florida after encountering a thunderstorm and slammed into the ground with such force that it created a crater and shattered the plane.
The National Transportation Safety Board is leading the investigation into the crash that killed all nine people aboard the Bahamas-bound Learjet, and it will likely take more than a year to determine the cause.
Dramatic bystander videos combined with the the disturbing final radio transmissions as the pilots realize their fate will give investigators important clues. The cockpit voice recorder would also help if investigators can find it intact.
“Our mission is to understand not just what happened, but why it happened, and to recommend changes to prevent it from happening again,” NTSB member Tom Chapman said.
Here’s what investigators are doing now and what comes next:
Investigators are gathering critical evidence
The NTSB team will spend days collecting every piece of the plane they can find. Investigators said Tuesday that pieces of a key part of the tail called the elevator, which controls the plane’s pitch, were found more than a mile away from the main crater. That confirms the plane started to break apart before impact.
Chapman said investigators are searching for the Learjet’s cockpit voice recorder because it could provide crucial details about what the pilots said to each other as they encountered turbulence, ice formed on the wings and they lost control of the aircraft.
“That will be very important data,” Chapman said. But being unable to find that recorder won’t doom the investigation. “Without it, our folks are very, very good. We’re still able to do some incredible detective work and determine how things transpired.”
The co-pilot told air traffic controllers that the plane was being thrown up and down more than 700 feet (213 meters) and she asked them for a better route through the area. It’s not clear why the pilots didn’t fly around the storms.
Torrential rains in Florida over the past week have hindered the investigators’ work. The crater filled with rainwater, possibly concealing parts of the wreckage under water, and a utility pole had to be removed.
The NTSB asked anyone who finds part of the plane to report that to investigators to collect.
The initial NTSB report will take about a month
The agency’s findings so far are limited, but its experts will publish a preliminary report describing the facts of what happened about 30 days after the crash. It won’t include analysis or cause, which will come in a later more detailed report.
The force of the crash and the fire destroyed much of the plane. Any evidence investigators are able to gather will be taken to a secure hangar where they can test or try to reassemble smashed components to better understand what happened.
Retired airline pilot and aviation safety expert John Cox said he doesn’t understand why the plane descended from its cruising altitude of 41,000 feet (12,500 meters) as it approached the storms. The pilots steered around a larger storm cell but appeared to head directly into a rapidly developing smaller one, Cox said.
“If I’m looking at thunderstorms, I’d rather be at 41 than at 35. You’ve got a better view, you’re more likely to be on top of it, or at least, in the very wispy tops of it,” Cox said. “I don’t understand why they came down.”
Investigators will try to determine whether they knew that storm cell was there, what the plane’s weather radar showed and whether the pilots checked any other weather services.
Investigators will dig deeper
Weather will be a key early focus of the investigation. NTSB experts will work with the National Weather Service and the Federal Aviation Administration to get a better idea of what the plane encountered at around 35,000 feet (11,000 meters).
Images that overlay the flight path atop weather radar maps show the Learjet flew directly into a small red storm cell that quickly worsened.
But the agency will consider a myriad of factors that may have contributed to the crash.
Investigators will review maintenance records and any history of problems with the plane. They will also interview officials at Upper Jets, the company that operated the flight, as well as air traffic controllers and people who work at the airport in Austin, Texas, from where the plane departed.
Videos and photos shot by bystanders can also provide crucial clues about what happened. The NTSB will also collect surveillance footage that might show the crash.
In certain high-profile crashes, the NTSB can hold investigative hearings during which investigators question people, as it did after last year’s UPS plane crash.
The final report could take more than a year
Generally, it takes 12 to 18 months for the NTSB to complete a crash investigation, but complicated cases can take longer. NTSB’s roughly 400 workers are pursuing more than 1,200 active investigations.
Final reports include extensive details about what happened and identify the probable causes.
The NTSB recommends changes to prevent similar crashes and improve safety, but it doesn’t have the power to require those changes to be installed or enforced.
The responsibility for adopting those falls to the FAA, the industry and Congress, all of whom have historically ignored NTSB recommendations, deeming such changes too costly and cumbersome.
Even when the FAA or Congress agree with the suggestions it can take years to approve new rules.