JAKARTA, Indonesia (AP) — Divers searching for a crashed jet’s cockpit voice recorder were sifting through mud and plane debris on the seabed between Indonesian islands on Wednesday to retrieve information key to learning why the Sriwijaya Air jet nosedived into the Java Sea over the weekend.
Indonesian navy divers on Tuesday recovered the flight data recorder from the jet that disappeared Saturday minutes after taking off from Jakarta with 62 people aboard. The information on both black boxes will be key to the crash investigation.
The 26-year-old Boeing 737-500 had resumed commercial flights last month after almost nine months out of service because of flight cutbacks caused by the coronavirus pandemic.
The U.S. Federal Aviation Administration sent an airworthiness directive requiring operators of various Boeing 737 aircraft models, including the 737-500, to carry out engine checks before they can be flown again after being out of service. The order followed reports of engines shutting down in mid-flight because of corrosion in a key valve.
Director General of Air Transportation Novie Riyanto said the plane was inspected on Dec. 2, including checks for engine corrosion, and was declared airworthy by Indonesia’s Transportation Ministry on Dec. 14. It resumed commercial flights on Dec. 22, according to ministry data. After returning to service, the plane made 132 flights, including the last one, according to aviation-data firm Flightradar24.
Aviation experts said planes that are parked for long stretches can be returned to flight safely.
"It depends on how the airline maintains the aircraft while it is grounded,” said William Waldock, an aviation-safety expert at Embry-Riddle Aeronautical University in Prescott, Arizona. He said airlines should run engines periodically and perform other maintenance. "It tends to keep everything lubricated, and it reduces the likelihood of corrosion building up in places you don’t want it to be,” he said.
John Goglia, a former member of the U.S. National Transportation Safety Board, said preparing a long-grounded jet can be an intensive and expensive chore, taking a team of mechanics up to two weeks to check engines and make sure that electronic, hydraulic and fuel systems are operating and free of contamination.
Goglia said that his initial thought on learning about the plane’s long grounding "was if they did the proper due diligence, because sometimes that stuff doesn’t show up for a little while.”
At least 160 divers were deployed Wednesday to boost the search for the recorder that holds conversations between pilots.