The mysterious disappearance of the Malaysian Airline passenger jet more than a week ago has filled the world equally with fascination and frustration.
TODAY posed the top questions and comments submitted by viewers through social media to a panel of aviation experts to glean their perspectives.
Here are the insights and explanations provided by Tom Casey, a former Boeing 777 pilot; Greg Feith, a former NTSB investigator, and Evy Poumpouras, a former Secret Service agent.
Q. Can’t you track all Flight 370 passengers’ cell phones? — @erinnn_011
Cell phones don’t work more than 2,000 feet above ground, Feith said.
“If you're not in a direct line of sight with a tower, you're not going to get a signal,” he said. “A cell needs to transmit to a tower. But if the plane is continually moving and between towers, the phone doesn't know which tower to sync to.”
Casey said it would be tough to track a passenger unless the person had a satellite phone.
"It's not like on 9/11 where the flight attendants and passengers were able to call because the planes were flying low in cell phone range,” he said.
Follow up Q: Couldn’t people use their cell phones as the plane landed?
Yes, but only if the plane landed intact, Poumpouras said.
“I would say that investigators have every passenger's cell phone and are doing reverse engineering to see where their last ping was — was it shortly before the plane took off when everyone's cell would've been activated? Or after that elsewhere?" she said.
Q. Is there concern that it’s been stolen to be used at a later date as a weapon or a bomb? —Vicki Weaver, Facebook
Terrorism is a possibility, mainly because “no one has taken any credibility for it yet,” Poumpouras said. “If it is terrorism, why hasn’t anybody raised their hand? One of the theories is that … there’s a greater plan basically in place and there’s more to follow.”
She pointed out that before September 11, the scenario of hijackers using American planes as weapons was inconceivable.
“It's very possible that this is the next level of sophistication that tops 9/11,” she said. “So one lesson is that we should always think a step ahead of the bad guy."
Q: Could an electrical fire or other mechanical problem have incapacitated the pilots and crew members? —Asked by multiple viewers.
Probably not, said Casey, who called the theory “really strenuous backward logic.”
“It's well outside the realm of probability. If the pilots noticed a fire or smoke or something wrong, they would've communicated it to air traffic control,” he said. “The rule is to maintain control of the aircraft, identify the problem and take appropriate action. And the first part of appropriate action is to notify somebody on the ground — mayday.”
Feith explained that smoke usually precedes fire and pilots would have put on their oxygen masks at the first sign of smoke in the cockpit.
“The airplane isn't going to catastrophically shut down and stop working,” he said. “You would expect somebody to radio in smoke or fire and say they're turning back to Kuala Lumpur but they never did that. “
He pointed out that nearly 20 years ago, when ValuJet Flight 592 caught fire, the pilot got on the radio to report the smoke and that they were returning to Miami. “They were at least able to get a radio call before they crashed into the Everglades and that plane was really on fire. “
Q. a) Can the computerized route be controlled from the electronics cavity beneath the cockpit where a person could hide? —@greatbeliever41
b) Could the plane be hacked into from the ground? Could someone override the program controls from another location? —@annekris3
The answer to both questions: Probably not.
“There's no way to get control of the plane from there. The only way to do it is from the cockpit,” Casey said. “This whole notion that someone had to have sophisticated knowledge of how to fly the plane isn't necessarily the case either.”
He said it’s also highly unlikely that hackers could work controls of a plane in flight.
“All of the controls are integral to the plane. It's its own entity and you can't hack into the computers on a plane and change its course. It's not possible even from a control tower,” he said.
Feith added that there are multiple layers of defense against outside interruption.
“The system has levels of protection that doesn't allow you to create a spurious signal,” he said. “There is no way to alter anything in the flight management system or the operation of the black box for that matter. You would have to demonstrate to the FAA multiple levels of redundancy. It will not allow you to have a single point failure by one single source.”
Q. Could the flight attendants outside the cockpit communicate with the ground crew if they felt threatened?
“Flight crew can't communicate with the ground outside of the cockpit. All the air-ground communications takes place from the cockpit,” Feith said. “There are systems on the market that you could install, like Inflight 911 Skybridge, that uses a WiFi-based system. But you'd have to have WiFi on the plane for it work.”
Q. Were there any onboard calls, tweets, text messages sent from passengers to loved ones during flight mh370? —@Hilladairy
“Nothing has been reported,” Poumpouras said.
Q. a) Will there be no voice evidence after the battery of the black box runs out or will it be saved? —@CMF53079
b) If the plane is in the ocean, can the black boxes still be viable? Or will water damage them if they're ever found? —@20ashdawn13
Both the cockpit voice recorder and flight data recorder are operated off aircraft generators.
“Thus, when the airplane crashes, the boxes stop recording data,” Feith said. “The pinger is battery-operated and water-activated on each box. It is used to locate the unit under water only.”
Both units are sealed in waterproof titanium cases. “If the titanium case breached but the circuit boards are intact, there are processes to dry the boards and make then functional to extract the data,” Feith said.
Poumpouras said black boxes are designed to withstand a great deal of force, up to “310-mile velocity impact.”
“Problem is finding them,” she said.
Q. Why do pilots have the ability to turn off the Transponders? Shouldn't they be on from the time the plane takes off to the time it lands? So why have an accessible on/off switch? —Becky Dluski, Facebook
Transponders provide air traffic control with a block of data regarding the flight number, the ground speed, the altitude and route of flight, Feith said.
“If the transponder remained ‘on’ on the ground, it would clutter (air traffic control) radar screens,” he said.
Poumpouras added that pilots are sometimes prompted to shut down transponders when they malfunction or send out erroneous information.