WASHINGTON — 16 people were killed when a hot air balloon hit a high voltage power line and crashed in Lockhart in July.

Now federal investigators are looking for answers.

Their first public hearing was held yesterday in Washington, DC.

The National Transportation Safety Board says the crash was the most deadly aviation accident in the country in more than 7 years.

Investigators are looking into several factors including existing government regulations and hot air balloon operating practices, including how pilots approach weather conditions.

The NTSB says during the pre-flight weather briefing, pilot Alfred "Skip" Nichols was told clouds could be a problem.

They say Nichols replied, “We find a hole and we go.”

When asked if they would fly under those conditions, all six hot air balloon experts who were called to testify Friday were in agreement.

Investigators also called into question Nichols’ medical history and record of drug and alcohol-related convictions.

A toxicology report showed the pilot had at least 10 medications in his system at the time of the accident.

Investigators say hot air balloon pilots are not required by law to pass a medical clearance.

The NTSB says the investigation remains underway.

It will reveal the probable cause of the accident and make recommendations during a future hearing.

To view the preliminary report, visit http://go.usa.gov/xkuST.

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