As the search for Malaysia Airlines flight MH370, carrying 239 on board, neared two weeks since its disappearance, "World News" viewers were invited to send questions about the missing plane and the search for it via Twitter using #ASKWORLDNEWS.

Related: What we know now about the missing flight.

ABC News consultant Tom Haueter, a former National Transportation Safety Board investigator, answered some of those questions below.

#askworldnews @DavidMuir Is it possible for the black box to be destroyed purposely?

- Kel (@kel3463) March 20, 2014

1. The CVR and FDR boxes are in the tail of the airplane and would be very difficult to reach in- flight. Also they are in hardened cases designed to withstand very high impact loads and fires . It would be possible to pull the circuit breakers on the boxes to prevent new data from being recorded

@ABCWorldNews Why don't airplane black boxes have a cloud backup, like other modern mobile devices? #askworldnews

- Kelsie (@KelsieLHarris) March 20, 2014

2. There is a back up to the FDR which is the quick assess recorder used by mechanics. However it's on the airplane too. There has been a great amount of discussion on broadcasting FDR data to a cloud type system but due to the few accidents the idea has not passed the cost-benefit evaluation. It would not be possible to broadcast the CVR due to privacy concerns

@ABC #askworldnews why can the tracking radar be turned off?

- Showjock (@Showjock2) March 20, 2014

3. The transponder can be turned off as occasionally transponders fail and provide inaccurate altitude information to controllers. Altitude information is needed to maintain separation with other aircraft. It's safer to to turn the transponder off and the pilots making altitude reports than have a broken transponder provide incorrect data. With the transponder off, radar can detect the primary return from the airplane but there would be no altitude information, or airplane identifier which makes tracking more difficult