“There was no medical emergency,” Antoon said. “There was no emergency in the cockpit. If there had been a decompression, there would have been a much higher descent rate. This was a controlled descent rate at a constant air speed.
“The voice recorder has already revealed that the captain was locked out of the cockpit,” he added.
In at least two other air crashes, similar circumstances may have been at work, Antoon said. Silk Air Flight 185 in December 1997 in Indonesia, and the more famous Malaysia Airlines Flight 370 over the Indian Ocean last March may have ended in similar ways, he said.
Some airlines require flight attendants to sit with pilots in cockpits when a second pilot leaves for momentarily.
“The procedures I flew with in the airlines, and I believe they are common to all U.S. airlines, is that when a pilot leaves a cockpit in a two-man situation, a flight attendant has to enter the cockpit and remains in the cockpit until the other pilot returns,” he said.
That wasn’t the case with Luthansa, of which Germanwings is a low-budget carrier, although Antoon expects airline procedures to be changed.
But he added: “I think if a pilot is hell-bent on crashing an airplane, he’s going to be able to do it, no matter what.”
Since Sept. 11, 2001, cockpit doors are designed to be armored, heavily structured and all but impossible to break into. If a pilot within a cockpit is incapacitated, a key code can be entered to open the door, Antoon said.
The Wall Street Journal reported Thursday that pilots of Airbus airplanes can defeat that key code access for several minutes in order to protect the cockpit from external access. The Journal said it reviewed Airbus training materials on the matter.
National aviation expert Jay Ratliff said most pilots with whom he has spoken are upset about the crash.
“Anytime someone within that tight knit community apparently commits an act of murder, as this could very well be, they recognize that it reflects on all pilots,” Ratliff said.
“They live in a world where passengers put their lives in their hands on a daily basis,” he added. “So the idea that someone within their community who is supposed to be in a position to protect the lives of the souls on board the aircraft could, in fact, have been an instrument in their death is something that has disturbed many people.”
Ratliff, a Miamisburg resident, expects an investigation to continue for 12 to 18 months, if not longer.
Like Antoon, Ratliff expects airlines to update procedures in the wake of Flight 9525. Lone pilots will no longer be left in control of cockpits, he believes.
“Norwegian Airlines today announced that they are going to do just that,” he said.
Another possible change, in his view: Requiring more experience from co-pilots. Co-pilot Andreas Lubitz, 28, joined Germanwings in 2013 and had 630 flight hours, Lufthansa said.
“In the U.S., because of some recent changes, you have to have a minimum 1,500 hours flight hours to sit in that right seat,” Ratliff said. “I suspect one of the things to be looked at internationally is an approach where that minimum-hour requirement is increased to be closer to what we have in the United States.”