REGIONAL Express (Rex) has defended its safety record after the third mid-air incident in less than a year.The airline yesterday confirmed that pilots on the airline’s late-afternoon flight between Sydney and Wagga last Thursday were forced to perform an emergency descent when they got a cockpit warning that the cabin was not pressurising normally.They took the plane down from 12,500 feet to 10,000 feet over a couple of minutes, said Rex managing director, Jim Davis, last night.The aircraft continued on to Wagga at that height and landed without incident.The plane had 25 passengers and four crew on board and was still climbing about 10 to 15 minutes out of Sydney when the warning was activated.The pilots descended to 10,000 feet because under regulations oxygen is not needed at that height, Mr Davis said.Mr Davis rejected a claim reportedly from one of the passengers that there was a strong and unusual smell in the cabin and there was a thin mist in the air.“There was no strong smell and no mist, I don’t know where that came from,” Mr Davis said.“Because of what the fault is, you would not expect that either.”Mr Davis said the warning was activated because the manual pressurisation system had not been set normally.Rex is investigating why the setting was incorrect, but it may be a maintenance error.“We know it was set wrong, but we don’t know how it was set wrong,” Mr Davis said.The airline has reported the incident to the Australian Transport Safety Bureau.Mr Davis said the emergency descent was steeper than normal and would have been noticed by the passengers.He confirmed one passenger had been given oxygen by cabin crew, but said it was not because the passenger area was short of oxygen.“We think she must have had an anxiety attack,” Mr Davis said.“Certainly, she would not have been deprived of oxygen at that point.“If anyone is distressed we always give them oxygen.”In July last year, a Rex plane departing from Orange experienced a failure of the outboard wheel of the right-hand landing gear, and in December on a flight from Ballina to Sydney the pilots received an unsafe nose gear indication.Mr Davis said the incidents should not shake passengers’ confidence in Rex. “With over 55,000 flying hours a year to have three minor incidents is still a good safety record,” Mr Davis said.