PHI Inc., a Lafayette-based helicopter company, reported its 2011 net earnings dropped to $4.9 million, or 31 cents per share, compared to $7.1 million, or 46 cents per share, a year earlier.

The company issued the report Tuesday evening, around five hours after the markets closed.

PHI said the decrease was due primarily to a $10 million drop in its Oil and Gas segment’s profit, a result of the BP Macondo well disaster and deepwater drilling moratorium. Although the company increased its revenue in the oil and gas segment, the flight hours and revenue related to deepwater drilling didn’t return to 2010 levels until the fourth-quarter. PHI began feeling the primary impacts of the BP disaster during the fourth quarter of 2010.

The company also had $8.6 million more in interest expenses due to the issuance of 8.625 percent senior notes.