ABC News' Matt Hosford Reports: The National Transportation Safety Board has opened an investigation into what happened aboard the go! airline flight that overshot its destination airport on February 13, 2008.   

NTSB investigators will interview the pilot and co-pilot of flight 1002 today via phone.  The NTSB was first alerted to this incident on Friday, February 15th, two days after it occurred.  They were unable to get any usable data from the cockpit voice recorder because these devices record on relatively short loops.   However, the NTSB has requested relevant air traffic control tapes.

One of the many issues that will be explored in the interview is whether or not the pilot and copilot fell asleep during the flight.   As part of the investigation the NTSB will have a human factors expert sit in on the interview with pilots.   

That expert will try to get a sense of the crew's actions to determine what may have precipitated this incident.   Involvement of a human factors expert is standard to any NTSB investigation.   The safety agency hopes to have a preliminary report available early next week.  Fatigue, particularly fatigue among pilots and air traffic controllers, is high on the NTSB's "most wanted" list of safety improvements.

Honolulu air traffic controller union representative Scott Sorenson tells ABC News that controllers on duty attempted to contact flight 1002 on emergency frequencies, but were unable to raise the airplane.  Controllers also attempted to raise the airline's operation center but initially received no response.   

A government aviation source also confirms that air traffic controllers made multiple unsuccessful attempts to reach the pilots.  Sorenson says once controllers had exhausted all means of contacting the airplane, the next step for FAA managers would have been to alert authorities of a potential hijacking or other serious issue.

ABC News has also learned that the Federal Aviation Administration is now looking into a second incident involving a go! Flight on February 12, 2008.   Air traffic controllers were unable to raise the pilots of a flight between Kona and Honolulu for 14 minutes.   FAA spokesman Ian Gregor stressed that at this point the agency has not made any determination on either incident and can not say that they are at all related.   Gregor says the FAA is seeking to speak to the pilots of the February 13th incident. 

Phoenix-based Mesa Airlines operates the airline in Hawaii under the brand "go!"  Today Mesa Airlines spokesman Paul Skellon says, "there is an investigation under way which we are cooperating with fully."  Skellon added, "the airline will not issue any comment until the investigation is completed."  According to the company website, go! began service in June of 2006 and offers service between 7 Hawaiian destinations.

There is no link at this time between pilot hiring and this incident.  However, Mesa, like many of its counterparts, is in the market for new pilots. A check of the company website yields a solicitation for first officers.  The airline requires a minimum of 500 hours of cockpit time for new hires. An aviation source familiar with pilot hiring practices say this is on the lower end of time for regional airlines, but above FAA requirements. A newly hired First Officer can expect to earn between $18.88 and $21.30 per hour.  The same source says Mesa is one of the lower paying regional airlines.  In 2007 Mesa hired in excess of 570 new pilots and is on target to hire an additional 400 plus by June.  In general any retention problems Mesa may have are similar to those of other regional airlines. Smaller airlines are often viewed by pilots as a launching point to bigger and better jobs at major airlines.