Malaysia B772 near Kuala Lumpur on Aug 23rd 2014, cabin pressure problems

A Malaysia Airlines Boeing 777-200, registration 9M-MRH performing flight MH-70 from Kuala Lumpur (Malaysia) to Tokyo Narita (Japan), was climbing out of Kuala Lumpur when the crew requested to stop the climb at FL210 due to a technical problem and to enter a holding. The crew subsequently requested a return to Kuala Lumpur without further detail and without requesting any priority or assistance, performed a rapid descent to FL100 (average rate of descent 2750fpm) and returned to Kuala Lumpur for a safe landing on runway 14L about 40 minutes after departure.

A passenger reported the crew announced they were returning to Kuala Lumpur over a safety issue.

A replacement Boeing 777-200 registration 9M-MRE reached Tokyo with a delay of 2.5 hours.

The occurrence aircraft was able to resume service 13 hours after landing.

The airline did not comment on the return.

Malaysia's Directorate of Civil Aviation reported the aircraft could not maintain the needed cabin pressure.