Narrative:

I was the captain on learjet 25D that departed from lzu on a flight to ict at approximately XA05 hours. We had received a clearance to climb to 8000 ft and were being vectored to choo choo VOR at cha. We were experiencing radio problems and departure control had called us and told us that our radios were weak and at times unreadable. The sic called departure again on the secondary radio with no improvement. He then tried a hand microphone with some improvement. During this same period I noticed that the cabin was not pressurizing. While we were attempting to pressurize the cabin, departure gave us a climb to 11000 ft and then a heading change. We climbed to 11000 ft and continued to run the checklist for the pressurization problem. During this period of time the sic acknowledged another call from ATC for a climb to 14000 ft and a frequency change to ZTL. ZTL gave us a climb to FL230 and direct to gqo. The sic set the altitude alerter to FL230 and told me to climb to FL230. At approximately this time we got the pressurization working properly and received another call from center wanting to know what altitude we had been assigned before we were given a frequency change to center. The sic attempted to answer them and they were unable to understand him. I transmitted and advised center that we had been experiencing pressurization problems and I did not know what the altitude assigned was before FL230. I also informed them that we were still at 11000 ft. Center advised us to remain at 11000 ft. Shortly after this we were given FL230 again and a frequency change to another center frequency. We then reported on the new frequency and continued the climb to FL230. After talking with the sic, he assured me that we had been assigned 11000 ft and then 14000 ft. While working on the pressurization problem I missed the call for 14000 ft and do not clearly recall the assignment to 11000 ft. This is a case of losing situational awareness because of the contributing factors of the radio problems and the pressurization problems. There should have been better communications on the flight deck and the PNF should have made certain the PF was aware of the instructions from ATC. I do not believe we violated any airspace restrs, other than we did not climb to 14000 ft when assigned this altitude. ATC did not give us any other indication that we were at the wrong altitude and did not give us an explanation for them not knowing what altitude we had been assigned. This was a high density airspace and a relatively busy time of day. The sic and myself have discussed this situation at length and have reviewed the CRM procedures that we should have been following and normally do follow. The radio problems were reported to maintenance and have been repaired. The pressurization problem was corrected at the time of the incident and has not been repeated.

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Original NASA ASRS Text

Title: FLC OF A LEAR 25D FAILED TO CLB TO THE NEXT ASSIGNED CLB ALT DUE TO DISTR OF A PRESSURIZATION PROB, RADIO PROBS, AND POOR COMS BY ATC.

Narrative: I WAS THE CAPT ON LEARJET 25D THAT DEPARTED FROM LZU ON A FLT TO ICT AT APPROX XA05 HRS. WE HAD RECEIVED A CLRNC TO CLB TO 8000 FT AND WERE BEING VECTORED TO CHOO CHOO VOR AT CHA. WE WERE EXPERIENCING RADIO PROBS AND DEP CTL HAD CALLED US AND TOLD US THAT OUR RADIOS WERE WEAK AND AT TIMES UNREADABLE. THE SIC CALLED DEP AGAIN ON THE SECONDARY RADIO WITH NO IMPROVEMENT. HE THEN TRIED A HAND MIKE WITH SOME IMPROVEMENT. DURING THIS SAME PERIOD I NOTICED THAT THE CABIN WAS NOT PRESSURIZING. WHILE WE WERE ATTEMPTING TO PRESSURIZE THE CABIN, DEP GAVE US A CLB TO 11000 FT AND THEN A HEADING CHANGE. WE CLBED TO 11000 FT AND CONTINUED TO RUN THE CHKLIST FOR THE PRESSURIZATION PROB. DURING THIS PERIOD OF TIME THE SIC ACKNOWLEDGED ANOTHER CALL FROM ATC FOR A CLB TO 14000 FT AND A FREQ CHANGE TO ZTL. ZTL GAVE US A CLB TO FL230 AND DIRECT TO GQO. THE SIC SET THE ALT ALERTER TO FL230 AND TOLD ME TO CLB TO FL230. AT APPROX THIS TIME WE GOT THE PRESSURIZATION WORKING PROPERLY AND RECEIVED ANOTHER CALL FROM CTR WANTING TO KNOW WHAT ALT WE HAD BEEN ASSIGNED BEFORE WE WERE GIVEN A FREQ CHANGE TO CTR. THE SIC ATTEMPTED TO ANSWER THEM AND THEY WERE UNABLE TO UNDERSTAND HIM. I XMITTED AND ADVISED CTR THAT WE HAD BEEN EXPERIENCING PRESSURIZATION PROBS AND I DID NOT KNOW WHAT THE ALT ASSIGNED WAS BEFORE FL230. I ALSO INFORMED THEM THAT WE WERE STILL AT 11000 FT. CTR ADVISED US TO REMAIN AT 11000 FT. SHORTLY AFTER THIS WE WERE GIVEN FL230 AGAIN AND A FREQ CHANGE TO ANOTHER CTR FREQ. WE THEN RPTED ON THE NEW FREQ AND CONTINUED THE CLB TO FL230. AFTER TALKING WITH THE SIC, HE ASSURED ME THAT WE HAD BEEN ASSIGNED 11000 FT AND THEN 14000 FT. WHILE WORKING ON THE PRESSURIZATION PROB I MISSED THE CALL FOR 14000 FT AND DO NOT CLRLY RECALL THE ASSIGNMENT TO 11000 FT. THIS IS A CASE OF LOSING SITUATIONAL AWARENESS BECAUSE OF THE CONTRIBUTING FACTORS OF THE RADIO PROBS AND THE PRESSURIZATION PROBS. THERE SHOULD HAVE BEEN BETTER COMS ON THE FLT DECK AND THE PNF SHOULD HAVE MADE CERTAIN THE PF WAS AWARE OF THE INSTRUCTIONS FROM ATC. I DO NOT BELIEVE WE VIOLATED ANY AIRSPACE RESTRS, OTHER THAN WE DID NOT CLB TO 14000 FT WHEN ASSIGNED THIS ALT. ATC DID NOT GIVE US ANY OTHER INDICATION THAT WE WERE AT THE WRONG ALT AND DID NOT GIVE US AN EXPLANATION FOR THEM NOT KNOWING WHAT ALT WE HAD BEEN ASSIGNED. THIS WAS A HIGH DENSITY AIRSPACE AND A RELATIVELY BUSY TIME OF DAY. THE SIC AND MYSELF HAVE DISCUSSED THIS SIT AT LENGTH AND HAVE REVIEWED THE CRM PROCS THAT WE SHOULD HAVE BEEN FOLLOWING AND NORMALLY DO FOLLOW. THE RADIO PROBS WERE RPTED TO MAINT AND HAVE BEEN REPAIRED. THE PRESSURIZATION PROB WAS CORRECTED AT THE TIME OF THE INCIDENT AND HAS NOT BEEN REPEATED.

Data retrieved from NASA's ASRS site as of July 2007 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.