Narrative:

A B737-800 arrived at approximately XA19 hours on mar/xa/07. The aircraft had a crew inbound report of a loud squeal from the cockpit handset. An amt was dispatched for corrective action. He and/or his lead amt ordered a svcable unit from stores. At around XA40 hours I was told by a lead amt to go by stores and get the handset and to relieve the amt at specified gate. The lead said stores had already 'pulled' the part. Indeed; I found the handset on a pick-up counter in the front of the stores area and proceeded to the gate. Once at the gate I told the amt to go and found that he had already removed the old handset. The handset has an electrical connector similar to a home phone landline. The new handset was plugged in and the captain and I accomplished a chkout of the unit. All operations appeared normal. I completed the logbook corrective action block and released the aircraft. In the line room later; I discovered there were no legible numbers on the old unit. For serial number 'off' I had to write 'unk' for unknown. Not having a good number off the old unit was a contributing factor. The shift change also added to the equation. To this day I don't know how they arrived at the part number I picked up in stores. I trusted it to be correct; and obviously it wasn't. Quality assurance found the effectivity issue and had the handset again replaced with the correct part number. There were; to my knowledge; no PIREPS of this system in the 4 days it flew on the aircraft.

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Original NASA ASRS Text

Title: A B737-800 ACFT COCKPIT PEDESTAL HANDSET FOR P/A AND INTERPHONE USE WAS REPLACED WITH AN INCORRECT PART.

Narrative: A B737-800 ARRIVED AT APPROX XA19 HRS ON MAR/XA/07. THE ACFT HAD A CREW INBOUND RPT OF A LOUD SQUEAL FROM THE COCKPIT HANDSET. AN AMT WAS DISPATCHED FOR CORRECTIVE ACTION. HE AND/OR HIS LEAD AMT ORDERED A SVCABLE UNIT FROM STORES. AT AROUND XA40 HRS I WAS TOLD BY A LEAD AMT TO GO BY STORES AND GET THE HANDSET AND TO RELIEVE THE AMT AT SPECIFIED GATE. THE LEAD SAID STORES HAD ALREADY 'PULLED' THE PART. INDEED; I FOUND THE HANDSET ON A PICK-UP COUNTER IN THE FRONT OF THE STORES AREA AND PROCEEDED TO THE GATE. ONCE AT THE GATE I TOLD THE AMT TO GO AND FOUND THAT HE HAD ALREADY REMOVED THE OLD HANDSET. THE HANDSET HAS AN ELECTRICAL CONNECTOR SIMILAR TO A HOME PHONE LANDLINE. THE NEW HANDSET WAS PLUGGED IN AND THE CAPT AND I ACCOMPLISHED A CHKOUT OF THE UNIT. ALL OPS APPEARED NORMAL. I COMPLETED THE LOGBOOK CORRECTIVE ACTION BLOCK AND RELEASED THE ACFT. IN THE LINE ROOM LATER; I DISCOVERED THERE WERE NO LEGIBLE NUMBERS ON THE OLD UNIT. FOR SERIAL NUMBER 'OFF' I HAD TO WRITE 'UNK' FOR UNKNOWN. NOT HAVING A GOOD NUMBER OFF THE OLD UNIT WAS A CONTRIBUTING FACTOR. THE SHIFT CHANGE ALSO ADDED TO THE EQUATION. TO THIS DAY I DON'T KNOW HOW THEY ARRIVED AT THE PART NUMBER I PICKED UP IN STORES. I TRUSTED IT TO BE CORRECT; AND OBVIOUSLY IT WASN'T. QUALITY ASSURANCE FOUND THE EFFECTIVITY ISSUE AND HAD THE HANDSET AGAIN REPLACED WITH THE CORRECT PART NUMBER. THERE WERE; TO MY KNOWLEDGE; NO PIREPS OF THIS SYS IN THE 4 DAYS IT FLEW ON THE ACFT.

Data retrieved from NASA's ASRS site as of January 2009 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.