A CRJ900's right pack began cycling on and off during climb out. Because the left pack was MEL'ed; t...

Attributes
ACN	858979
Time
Date	200911
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Light	Daylight
Aircraft 1
Make Model Name	Regional Jet 900 (CRJ900)
Operating Under FAR Part	Part 121
Flight Phase	Climb Initial Climb
Flight Plan	IFR
Component
Aircraft Component	Air Conditioning and Pressurization Pack
Person 1
Function	Pilot Not Flying First Officer
Experience	Flight Crew Last 90 Days 13 Flight Crew Total 1600 Flight Crew Type 1000
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

Aircraft had a deferred left pack and the right pack began cycling on and off as the isolation and bleed valves began opening and closing randomly on climb out. The psi going to the right pack began to fluctuate causing the right pack to drop off line randomly and then psi would increase causing the pack to come back online. We were instructed by ATC to climb from 13;000 ft to 17;000 ft and asked if we could maintain 15;000 ft. The controller told us to level off at 15;000 ft. We told them we needed to contact maintenance; were working out a problem; were not declaring anything and would get back to them shortly. As we continued on the departure we were getting close to an intersection which says to cross at FL180 or above. I contacted ATC to verify we were okay at 15;000 ft. The controller responded we were okay at 15;000 ft but the next controller would have to climb us. Shortly after; we informed ATC we would be returning and were given vectors.

Original NASA ASRS Text

Title: A CRJ900's Right Pack began cycling ON and OFF during climb out. Because the Left Pack was MEL'ed; the aircraft was returned to the departure airport.

Narrative: Aircraft had a deferred left pack and the right pack began cycling ON and OFF as the Isolation and Bleed valves began opening and closing randomly on climb out. The PSI going to the Right Pack began to fluctuate causing the Right Pack to drop off line randomly and then PSI would increase causing the Pack to come back online. We were instructed by ATC to climb from 13;000 FT to 17;000 FT and asked if we could maintain 15;000 FT. The Controller told us to level off at 15;000 FT. We told them we needed to contact Maintenance; were working out a problem; were not declaring anything and would get back to them shortly. As we continued on the departure we were getting close to an intersection which says to cross at FL180 or above. I contacted ATC to verify we were okay at 15;000 FT. The Controller responded we were okay at 15;000 FT but the next Controller would have to climb us. Shortly after; we informed ATC we would be returning and were given vectors.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

A CRJ900's right pack began cycling on and off during climb out. Because the left pack was MEL'ed; the aircraft was returned to the departure airport.