The sole survivor of the crash of Cougar flight 491 and people who lost loved ones in the tragedy fear their concerns are being ignored by the federal transport minister.

Their lawyer has sent three letters to the minister’s department but by Friday they had not received a response from Transport Minister Denis Lebel or his department.

"As far as I know, there has been no acknowledgement that we’ve even sent a letter," said Lori Chynn. Her husband John Pelley, 41, died when the helicopter ferrying oil workers offshore went down on March 12, 2009.

They want to know why the Sikorsky S-92a’s main gearbox was certified to fly for 30 minutes after losing oil pressure - when it clearly couldn't.

They also want to know why a similar S-92a main gearbox failure in Australia, months before the crash southeast of St. John’s, wasn't followed up and acted on more quickly.

"Those points were not addressed in the Transportation Safety Board’s report. So we are seeking answers to those issues. It’s a long time now and we’d like to have some clarification," said Chynn, of Deer lake, western Newfoundland.

The Transportation Safety Board of Canada (TSB) released its final report on the crash on Feb. 9, 2011.

The families wrote a letter asking the federal transport minister to investigate the certification of the S-92a on Feb. 18, 2011.

"Did Transport Canada succumb to pressure from the United States Federal Aviation Administration (FAA) or Sikorsky, or did they simply fail to recognize a serious safety/certification issue?" said the letter to then Transport minister Chuck Strahl.

Law firm Camp Fiorante Matthews wrote the Transport Minister again on Nov. 4.

"These families have been devastated by this accident. They are entitled to the courtesy of a response. More troubling is the fact that it appears from your silence that you are unwilling to investigate how this helicopter was certified so that the steps necessary to prevent recurrence of this tragedy can be properly identified and implemented," said the letter.

Joe Fiorante is the lawyer representing sole survivor Robert Decker and the families.

"Our basic aviation safety system, the safe guard we all rely on, failed in this case and it needs to be explained to us why it failed and what steps are being taken to prevent a similar failure," he said.