Montreal-based Bombardier is awaiting the causes of two deadly crashes over the past couple of days involving its commercial and business planes.

At least 50 people were killed today when a US Bangla Airlines Q-400 passenger plane carrying 71 people from Bangladesh crashed and burst into flames as it landed in Nepal's capital.

The incident came a day after a private Turkish Challenger 604 business jet crashed and burst into flames on an Iranian mountainside. All 11 people on board perished.

That plane was carrying a wealthy businessman's daughter and her friends home from a Dubai bachelorette party.

Bombardier spokesmen say they were saddened by the accidents but insisted the planes are safe and reliable.

Mark Masluch of the business jet division called the back-to-back crashes an "unfortunate coincidence."

The causes of both crashes aren't immediately available.

Bombardier is waiting for invitations from Nepalese and Iranian officials before sending investigation teams to the crash sites.

The Q-400 has sustained several landing gear incidents over the years but this is just the second crash of the aircraft resulting in death.