Even with a full plane of survivors, question is: why take off?

CHICAGO (WLS) -- As investigators in Mexico begin searching for what caused a passenger jet loaded with Chicagoans and other Americans to crash, there is no shortage of evidence that bad weather was a prime factor.

Surviving passengers, Aeromexico executives and government officials have all noted - or blamed - the gathering storm that seemed to force the plane back to earth right after liftoff from the northern Durango state airport.

The questions not answered yet: Why did the Mexico City-bound Embraer 190 attempt to takeoff in those conditions? Who made the decision to try to fly in such bad weather?

Videos shot by passengers onboard the jetliner reveal heavy rain, low visibility and winds as the aircraft rolls down the runway. Passengers reported hail was also falling at the time and lightning.

Time lapse video from Durango at the time of the plane crash shows storms and low clouds rolling in over the airport. Weather observers in the sector reported shifting winds at the time of the crash; thunderstorms in the area and marble-sized hail.

Both flight recorders have been recovered by Mexico's civil aviation agency which is leading the investigation.

The jet smashed nose-first into scrubland near the runway shortly after take-off. All 103 passengers and crew survived by evacuating the plane before it caught fire.

While nearly everyone on the flight suffered minor injuries, the pilot is hospitalized in critical condition-and authorities say he likely holds the answer as to why a take-off of flight #2431 was attempted in such poor and declining weather conditions.

"Every country has its own standards but most mirror the U.S.," ABC News aviation consultant Steve Ganyard told the I-Team on Wednesday.

"Still, the pilot always has the final decision" said Ganyard, a Northwestern graduate and former Marine Corps fighter pilot.

In real life flight situations, commercial air pilots say there are several factors at play in any marginal liftoff condition:

1. Government air traffic controllers who give clearance to depart

2. Airline operations officials who deliver the company's policies and preference (which may vary based on size of airline, nation of register, etc.) Generally more conservative decisions prevail at large airlines.

3. The cockpit crew-that technically ALWAYS has the final decision because they control the plane.

The Aeromexico aircraft, originally purchased and used by two U.S. airlines, was ten years old. Neither the jetliner nor the Durango airport show any history of serious operational issues or violations. The identity and history of the flight crew were not known on Wednesday evening,

but the airline praised the crew's efforts to evacuate safely.

Under international rules, Mexico is leading the investigation with support from Brazil, where the Embraer jet was designed and built, and from the United States, where General Electric made the jet's engines.

From the U.S., two investigators from the National Transportation Safety Board are being deployed to assist in the investigation.