Date: 201203
Local time of day: 1801-2400
Location: ZZZ.ARTCC, US
Flight conditions: VMC
Light: Night
Aircraft: MD-83
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Ferry / Re-Positioning
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Aircraft component: Pressurization Control System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP)
Human factors: Time Pressure; Training / Qualification; Communication Breakdown; Distraction
Anomaly: Aircraft Equipment Problem Critical; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Aircraft Equipment Problem Dissipated; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Took Evasive Action
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: While in cruise at FL340 on a ferry flight back from a 'C' check; we were three people in the cockpit; the Captain; the Director of Quality Control; and me. While en route the cabin altitude indicator started to rise. I called it to the Captain's attention; and he replied 'let me know if it reaches 9;000 FT.' A minute after when it reached 9;000 FT I called it to his attention. A couple of seconds after we got the cabin altitude light; when the attention of the Captain was directed to the cabin altitude and differential pressure indicator. I noticed the aircraft started to depart our assigned altitude of FL340; so I called it to the Captain's attention 'altitude' then for a second time again 'sir altitude we are descending.' For a third time I questioned him if he wanted Altitude Hold mode. He kept looking at the cabin altitude and differential pressure indicator with the other company Employee in the jump seat. During this time we were already 350 FT below our assigned altitude; so I took the action to ask ATC for a lower altitude a second after the Captain heard me on the radio he said 'ask for lower;' but don't sound too desperate. At that point ATC gave us clearance to descend to FL280 first then a split second after gave us clearance again to descend to FL240. While the Controller was giving me this clearance I told the Captain 'altitude' and pointed his altimeter; and he replied '(EXPLETIVE)' (EXPLETIVE) what happened' and he was trying to climb back up to FL340 and at that time we were 480 FT below our assigned altitude. I told him 'sir; sir; we are cleared now to FL290' and that split second after I told him; we were cleaered to FL240 'set and arm ' and I replied again 'sir FL240 set and armed' and pointed to the FMA. I just wanted to make sure we were on the same page. During this time I was also monitoring back and forth the cabin altitude indicator when we got the cabin altitude light I got my oxygen mask ready and rapidly turn and told our employee on the jumpseat to put his mask on. While on the descent the cabin rise to 13;400 FT; but when we were below FL280 the cabin started to go down within the limits. When he queried us 'is everything OK ' the Captain replied on the mic. 'Yes everything is fine'; we just got an annunciation that's all; but everything is fine.' When I told our employee in the jump seat to get his oxygen mask out I also told my Captain; but he was a little confused or distracted by other things in the flight; so I called to his attention. I said 'sir; sir; correct [me] if I am wrong but the regulation calls for if we are in a cabin pressure altitude of 10;000 to 12;500 for more than 30 minutes we have to be in oxygen.' He replied 'that's correct' ; he looked at the cabin altitude and differential pressure indicator and he replied '(EXPLETIVE) I didn't know it got that high ; because when he looked it was at 11;200 and descending at like 1;200 FT per minute. In the MD83 we get the Cabin Altitude light when the cabin reaches 10;000 FT. I still don't understand why he said I did not know it got that high; because the moment that light is on you know you are at 10;000 or above cabin altitude.




Synopsis: A MD83's cabin climbed about 10;000 FT while on a ferry flight following a 'C' Check but the Captain were very slow to respond to the anomaly; never donned oxygen nor declared an emergency. The cabin began to descend below FL280.