Canadian airlines are no longer required to have two crew in the cockpit at all times, following the expiration today of an order issued by the government after a co-pilot deliberately downed a Germanwings jet in 2015.

Since the crash that killed 150 people, Transport Canada has been examining if there was any way to "mitigate the potential risk" of a similar tragedy unfolding in Canada, according to a letter sent to airlines and obtained by CBC News.

"The conclusion of the … analysis was that Transport Canada's current regulatory program, without the requirements of the interim order, effectively mitigate this risk of an unfit pilot operating a commercial aircraft," wrote Aaron McCrorie, a director general with Transport Canada in the letter dated May 29.

Transport Canada told CBC News in a statement that having two crew members in the cockpit at all times could "reduce the number of flight attendants in the cabin, which could potentially have an impact on passenger safety, especially in an emergency."

Leon Cygman, chair of the Mount Royal University aviation program, said he's a "little surprised" by the decision.

"I would support a two-crew environment at all times," said Cygman, who added that Canada's aviation industry is very safe.

Authorities said that Andreas Lubitz deliberately sent the airliner into a descent and locked the captain out of the cockpit before the crash. (Facebook/Associated Press)

"The flying public is a nervous bunch at best, even though flying is safer than driving in some cases.… I think it just reassures the public that if one has a medical emergency the other can take over."

Canada in some cases exceeds international standards

After the Germanwings crash, Canada's minister of transport ordered at least two flight crew had to be in the cockpit at all times. That would ensure that at least one person could unlock the door if there was an emergency, according to the original memo sent to airlines two years ago.

The rule meant that when one of the two pilots went to the washroom, a flight attendant, flight director, or another pilot would come into the cockpit so there was always two people there at all times.

A French Gendarmerie rescue helicopter flies over the debris of the Airbus A320 deliberately crashed by the co-pilot, near Seyne-les-Alpes, French Alps, in March 2015. (Emmanuel Foudrot/Reuters)

Co-pilot Andreas Lubitz, who had suicidal tendencies and depression in the past, locked the captain out of the cockpit on March 24, 2015, and sent Flight 4U9525 from Barcelona to Duesseldorf straight into a mountainside, killing everyone on board.

Doctors required to report pilots' mental health

The crash sparked concerns worldwide about safety and led to countries including Canada to conduct a comprehensive risk assessment, including meeting with key groups in the industry to see if enough is being done.

In the end, Transport Canada told airlines that it found its current aviation medical program is strong enough.

"This program aligns, and in some cases, exceeds the approaches taken internationally," McCrorie wrote in the letter to airlines.

To become a pilot in Canada you must have a medical certificate and be assessed by a doctor, in some cases every six months to a year, depending on the pilot's age. Specially trained medical examiners for pilots include in their assessment a mental health diagnosis, says the letter.

Unlike other countries, Canada requires all doctors to alert Transport Canada if a pilot has any conditions that may constitute a hazard to aviation safety. When the government finds out that a health issue "poses a clear and immediate threat to flight safety outside the norm, Transport Canada suspends the pilot's medical certificate," wrote McCrorie.

In a statement to CBC News, Transport Canada said that it also carefully reviewed the French BEA's report and recommendations after the Germanwings incident and said there was no recommendation to have two people in the cockpit at all times.

"Transport Canada will not renew the interim order or propose regulatory amendments," spokesperson Natasha Gauthier wrote in a statement.

"Canada has one of the safest aviation systems in the world, and we continuously work to improve safety,"

Pilot associations satisfied

Two major pilot associations said they are satisfied that Transport Canada is dropping the two-crew cockpit rule.

"The Air Canada Pilots Association is pleased," it wrote in a statement to CBC. "We think that this strikes the right balance of aircraft safety while also ensuring adequate supervision in the passenger cabin."

Canada's president of the Air Line Pilots Association, Dan Adamus, said the pilot community has confidence in the current system.

"The procedures in place will continue to be safe and secure," said Adamus.

Transport Canada held its first summit of its kind into support for pilots with mental health last week in Gatineau, Que.

It's now planning to put together a toolbox of resources to give to airlines. Transport Canada is also planning to work with smaller airlines to try to find a way to offer peer-to-peer support for its pilots, similar to the major airlines — a gap it discovered in the current system.