A family is suing Alaska Airlines and a contractor after a disabled 75-year-old grandmother suffered a fall down a Portland International Airport escalator in June and later died.

Video captured the moment that Bernice Kekona, seat-belted to her power wheelchair, tumbled and crashed down an escalator, landing near the bottom with the heavy chair on top of her.

After her flight from Hawaii landed in Portland in June 2017, the family says they hired a contractor to make sure Kekona arrived safely to her connecting flight. But now they argue the airline and its contractor did not provide the service as promised.

A family is suing Alaska Airlines and a contractor after a disabled 75-year-old grandmother suffered a fall down a Portland International Airport escalator in June and later died

Video captured the moment that Bernice Kekona, seat-belted to her power wheelchair, tumbled and crashed down an escalator, landing near the bottom with the heavy chair on top of her (left and right)

After tumbling nearly 21 steps, the clip shows a man, riding up the opposite side of the pair of escalators, leaping over the sides to try and help Kekona as several other rush over to lift the heavy chair off of her (left and right)

Kekona's family (pictured) say she suffered trauma to her head and chest, a cut to her Achilles tendon and gashes on the side of her face

In airport surveillance video obtained by KXLY, Kekona is shown at the top of an escalator, which she later said she thought was an elevator.

After tumbling nearly 21 steps, the clip shows a man, riding up the opposite side of the pair of escalators, leaping over the sides to try and help Kekona as several other rush over to lift the heavy chair off of her.

Despite eventually being sat upright, Kekona's family says she suffered trauma to her head and chest, a cut to her Achilles tendon and gashes on the side of her face.

The family's lawyer says Kekona suffered constant, serious pain in the months following the incident.

In September, the wound to her tendon became so infected that doctors were forced to amputate her leg below the knee, according to a lawsuit filed by the family. Her blood pressure never recovered following the surgery and Kekona died the next day.

Her family is now suing Alaska Airlines and Huntleigh, USA for failing to provide what they say was agreed upon gate-to-gate transportation.

Despite eventually being sat upright, Kekona's family says she suffered trauma to her head and chest, a cut to her Achilles tendon (right) and gashes on the side of her face (left)

In September, the wound to her tendon became so infected that doctors were forced to amputate her leg (left) below the knee, according to a lawsuit filed by the family. Her blood pressure never recovered following the surgery and Kekona died the next day

Her family is now suing Alaska Airlines and Huntleigh, USA for failing to provide what they say was agreed upon gate-to-gate transportation

The family is seeking reparation for damages, expenses and any 'further relief as the court may deem just and proper' resulting from Kekona's fatal fall, according to court documents.

'Between her injury and her death, Bernice incurred almost $300,000 in medical bills to treat her injuries from the fall,' attorneys Brook Cunningham and Troy Nelson wrote.

According to the lawsuit, Kekona showed her ticket to an Alaska Airlines employee at her arrival gate, who pointed her in the direction she needed to go in.

Minutes later Kekona was seen on video moving through the airport, confused and lost. She stopped at a security checkpoint and an airport store looking for her departure gate, the lawsuit claims.

Huntleigh, USA, who is contracted by Alaska Airlines for disability services through the airport, told KXLY it can't comment yet because it has not seen the lawsuit filed Wednesday in King County Superior Court.

According to the lawsuit, Kekona (pictued with family) showed her ticket to an Alaska Airlines employee at her arrival gate, who pointed her in the direction she needed to go in

Minutes later Kekona (pictured) was seen on video moving through the airport, confused and lost. She stopped at a security checkpoint and an airport store looking for her departure gate, the lawsuit claims

Alaska Airlines said an investigation is continuing, but 'it appears that Ms Kekona declined ongoing assistance in the terminal and decided to proceed on her own to her connecting flight

Alaska Airlines said an investigation is continuing, but 'it appears that Ms Kekona declined ongoing assistance in the terminal and decided to proceed on her own to her connecting flight.'

The airline also noted her reservation did not note any 'cognitive, visual or auditory impairments.'

Alaska Airlines also told ABC News that Kekona had the right to decline wheelchair services.

The company added that it was 'heartbroken by this tragic and disturbing incident'.