Narrative:

Ontario tower called for release of a LR35 on prado SID. I instructed tower to issue 3;000 on departure because I had a BE60 at 4;000 on a vector for the ILS approach into the riverside airport. The prado SID is a climbing left turn to the paradise VOR. The aircraft came off the airport stating that he was runway heading. I gave radar contact and asked the pilot if he was in the left turn. I did not get a response. The aircraft again checked in but was not responding to my calls and continued on runway heading. I called the tower and told them that he was cross channeled and to advise them. The aircraft finally came on the frequency and I got them to start a left turn to the paradise VOR; almost eight miles off the runway. I issued traffic to the BE60 and advised that he would be stopping at 3;000. I observed the LR35 climbing out of 3;200 then 3;300 and then restated that he should be at 3;000 and issued traffic. He went back down to 3;000. When I looked up again he was out of 3;400 climbing into the BE60. I quickly restated 3;000 and decided that I needed to turn the BE60 out of the way because this pilot was not cooperating. I gave the BE60 an immediate left turn to 200 to establish course divergence. The LR35 responded with the heading that I gave the BE60. I went back to the LR35 and told them to go to paradise and climb to 7;000 since he was already now behind the BE60. Aircraft responded that he was having some type of equipment malfunction. Nothing could have saved this. The pilot was way behind his aircraft due to malfunction of equipment evidently.

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Original NASA ASRS Text

Title: A near loss of separation occurred when a LR35 repeatedly failed to maintain an issued altitude.

Narrative: Ontario Tower called for release of a LR35 on PRADO SID. I instructed Tower to issue 3;000 on departure because I had a BE60 at 4;000 on a vector for the ILS approach into the Riverside Airport. The PRADO SID is a climbing left turn to the Paradise VOR. The aircraft came off the airport stating that he was runway heading. I gave RADAR contact and asked the pilot if he was in the left turn. I did not get a response. The aircraft again checked in but was not responding to my calls and continued on runway heading. I called the Tower and told them that he was cross channeled and to advise them. The aircraft finally came on the frequency and I got them to start a left turn to the Paradise VOR; almost eight miles off the runway. I issued traffic to the BE60 and advised that he would be stopping at 3;000. I observed the LR35 climbing out of 3;200 then 3;300 and then restated that he should be at 3;000 and issued traffic. He went back down to 3;000. When I looked up again he was out of 3;400 climbing into the BE60. I quickly restated 3;000 and decided that I needed to turn the BE60 out of the way because this pilot was not cooperating. I gave the BE60 an immediate left turn to 200 to establish course divergence. The LR35 responded with the heading that I gave the BE60. I went back to the LR35 and told them to go to Paradise and climb to 7;000 since he was already now behind the BE60. Aircraft responded that he was having some type of equipment malfunction. Nothing could have saved this. The pilot was way behind his aircraft due to malfunction of equipment evidently.

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.