A pilot is being investigated after locking passengers on a crashed plane for more than an hour.

The captain was landing the Boeing 737 when it skidded off the runway in heavy rain at the Mae Fah Luang - Chiang Rai International Airport in northern Thailand on Sunday evening July 30.

Passengers recorded video after allegedly being forced to stay inside the hot cabin with no air conditioning for at least 60 minutes. They said they began feeling sick, with temperatures outside above 30 degrees Celsius making the cabin even hotter and stuffier leading to breathing problems.

The pilot cut the engines and the lights were turned off - leaving passengers in darkness - and told those onboard struggling with the conditions that 'passengers are not allowed on runways'.

Customers said they pleaded with the cabin crew to be let off the stricken vehicle but were ignored and told to wait. The pilot reportedly refused to open the doors and activate the emergency slide. However, he relented after an hour and opened one of the eight emergency doors on the plane to allow some passengers to leave.

The pilot has now been summoned by aviation regulators to explain why he did not allow passengers to leave immediately after the crash - with international aviation protocols requiring all passengers to be evacuated within 90 seconds of a serious incident.

Suttipong Kongpool, director general of the Civil Aviation Authority of Thailand (CAAT), said on Monday that the chief pilot of flight DD108 will be ordered to defend the decision.

He said: 'The rationale behind the decision is what the CAAT needs to hear from the captain.'

Mr Kongpool said that passengers could stand on runways during emergencies but the rules were at the discretion of the captain.

The aviation chief added: 'The captain is the one who makes the decision on evacuation after assessing the situation, including external factors.'

Officials said the captain cut the engines on the Boeing 737-800 but ordered passengers to wait for buses to arrive to take them from the runway to the terminal. He reportedly told passengers it would be 'dangerous' for them to be standing outside near the runway, even though no further flights were due to land that night at the airport in the north of the country.

Transport Minister Saksayam Chidchob said the country's aviation authority has launched an investigation as well as low-cost carrier Nok Air, a publicly traded company known for its bright liveries with the face of birds on the noses of its jets.

Nok Air said that passengers onboard flight DD108 were taken safely to the airport terminal but there were significant delays removing baggage from the hold.

Airport boss Somchanok Tiemtiebrat added: 'The aircraft HS-DBR skidded off the runway while the pilot landed at Mae Fah Luang Chiang Rai International Airport.

'The weather at the time of the incident was unfavourable as there was a thunderstorm, however, the pilot was able to land the aircraft safely without any injuries. Airport staff, the airline took care of the facility and provided accommodation for passengers.'

Officials have now removed the aircraft from the grass but the landing gear collapsed while it was being towed and it remained stuck on the runway in the early hours of the morning on August 4. The airport has now been closed until September amid safety fears.

The Boeing 737-800 is an earlier model to the notorious 737 Max which has twice crashed, killing 346 people as well as suffering at least six mid-air emergencies.

The Boeing 737-Max, an upgrade to the Boeing 737-800, was the subject of the damning Netflix documentary Downfall: The Case Against Boeing' released earlier this year.