The families of the people killed in South Korea Jeju Air crash hoped remains of their loved ones can be identified soon as investigators race to identify the cause of the worst aviation disaster in the country’s history.

Investigators are examining bird strikes and weather conditions as possible factors in the crash, fire officials have said. Experts say many questions remain, including why the plane, powered by two CFM 56-7B26 engines, appeared to be traveling so fast and why its landing gear did not appear to be down when it skidded down the runway and into a wall.

READ: Flags fly at half-mast as South Korea probes its worst plane crash

Members of the National Forensic team continued to scour the wreckage, looking for traces of human remains, investigators told a news briefing with family members in Muan International Airport.

South Korea's acting President Choi Sang-mok ordered an emergency safety inspection of the country's entire airline operation system.

All 175 passengers and four of the six crew were killed when a Jeju Air Boeing 737-800 belly-landed and skidded off the end of the runway at Muan International Airport, erupting in a fireball as it slammed into a wall. Two crew members were pulled out alive.

(Production: Daewoung Kim, Hyunyoung Yi, Angie Teo)