Narrative:

I am writing this letter to inform you of a potential aviation safety problem. I own a cessna 340, and I had my deicing boots replaced at company at the akron-canton airport on jul/xx/95. I picked up the plane that afternoon to fly to chicago. The head of the facility, mr. X said the plane was ready and everything checked out, and I took off for my destination. En route I cycled the new boots as a test, and I immediately lost both vacuum pumps! I was in VFR conditions, canceled my IFR flight plan, and finished the trip easily in total VFR conditions. The FBO at dupage (dpa) airport had just closed -- it was XA00 pm -- and the next morning I talked to the maintenance supervisor who confirmed that my 2 vacuum pumps had both failed and needed to be replaced. He said that the date the pumps were manufactured was 1990, but he couldn't tell when they were installed. I had new engines installed in sep/xx/94, so I called and they confirmed that they didn't change the pumps then because they were still good. My mechanic, at thermal airport, was on vacation and just returned this week, so I couldn't get his input. I called the company right away and told mr. X what had happened. He was very concerned, but when I asked him how this could have happened after he had tested them, he then said that they do not test them after they are installed, and that when they do test them, they use their own air source and not the plane's vacuum system for the test!! I was told that, rarely, older vacuum pumps can fail when they try to cycle new boots. Since my pumps were not 'old' and had been functioning perfectly to that day, my mechanic and I are currently trying to sort out if company has any responsibility for the failure and the $3000 bill for new pumps. But that is not the purpose of this letter. The point of this letter to you is to make sure that company changes its practice of not cycling the new boots with the airplane's vacuum system. I am sure many pilots, especially in the winter, leave akron in clouds and icing conditions, and I am sure that very few of them have new vacuum pumps. If any of them need to use their new boots and have a dual vacuum failure, thus losing their altitude indicator and directional gyroscope, they would be in a perilous position trying to fly in instrument conditions with only 'needle, ball, and airspeed. I told this to mr. X and he said they would take it under advisement. For the safety of my fellow pilots, I feel it should be mandatory for company and all other installer of deicing boots, to be required to cycle new boot installations with the airplane's vacuum system before the pilot is allowed to fly the plane. Callback conversation with reporter revealed the following information: reporter states that his mechanic says it is very unusual for both vacuum pumps to fail at the same time. That is why there are 2 pumps, so 1 is a back up. There is apparently no way to determine if there is any connection between boot installation and the pump failures. The company, if there is anything they did wrong, they will accept responsibility. The reporter plans to install an electrical system to replace 1 of the vacuum pumps on his instruments so that he has a more reliable back up. Rptrs primary concern is that the word be circulated regarding the testing procedures of any company that installs deicing equipment so the pilot can assure that the equipment is tested using the aircraft vacuum pumps, not just the company air source. He feels sure that had he been in IFR conditions he would not be here to tell about it. Reporter also plans to send a letter to the cessna twin owners group.

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Original NASA ASRS Text

Title: SMT HAS VACUUM PUMP FAILURE AFTER INSTALLATION OF DEICING BOOTS.

Narrative: I AM WRITING THIS LETTER TO INFORM YOU OF A POTENTIAL AVIATION SAFETY PROB. I OWN A CESSNA 340, AND I HAD MY DEICING BOOTS REPLACED AT COMPANY AT THE AKRON-CANTON ARPT ON JUL/XX/95. I PICKED UP THE PLANE THAT AFTERNOON TO FLY TO CHICAGO. THE HEAD OF THE FACILITY, MR. X SAID THE PLANE WAS READY AND EVERYTHING CHKED OUT, AND I TOOK OFF FOR MY DEST. ENRTE I CYCLED THE NEW BOOTS AS A TEST, AND I IMMEDIATELY LOST BOTH VACUUM PUMPS! I WAS IN VFR CONDITIONS, CANCELED MY IFR FLT PLAN, AND FINISHED THE TRIP EASILY IN TOTAL VFR CONDITIONS. THE FBO AT DUPAGE (DPA) ARPT HAD JUST CLOSED -- IT WAS XA00 PM -- AND THE NEXT MORNING I TALKED TO THE MAINT SUPVR WHO CONFIRMED THAT MY 2 VACUUM PUMPS HAD BOTH FAILED AND NEEDED TO BE REPLACED. HE SAID THAT THE DATE THE PUMPS WERE MANUFACTURED WAS 1990, BUT HE COULDN'T TELL WHEN THEY WERE INSTALLED. I HAD NEW ENGS INSTALLED IN SEP/XX/94, SO I CALLED AND THEY CONFIRMED THAT THEY DIDN'T CHANGE THE PUMPS THEN BECAUSE THEY WERE STILL GOOD. MY MECH, AT THERMAL ARPT, WAS ON VACATION AND JUST RETURNED THIS WEEK, SO I COULDN'T GET HIS INPUT. I CALLED THE COMPANY RIGHT AWAY AND TOLD MR. X WHAT HAD HAPPENED. HE WAS VERY CONCERNED, BUT WHEN I ASKED HIM HOW THIS COULD HAVE HAPPENED AFTER HE HAD TESTED THEM, HE THEN SAID THAT THEY DO NOT TEST THEM AFTER THEY ARE INSTALLED, AND THAT WHEN THEY DO TEST THEM, THEY USE THEIR OWN AIR SOURCE AND NOT THE PLANE'S VACUUM SYS FOR THE TEST!! I WAS TOLD THAT, RARELY, OLDER VACUUM PUMPS CAN FAIL WHEN THEY TRY TO CYCLE NEW BOOTS. SINCE MY PUMPS WERE NOT 'OLD' AND HAD BEEN FUNCTIONING PERFECTLY TO THAT DAY, MY MECH AND I ARE CURRENTLY TRYING TO SORT OUT IF COMPANY HAS ANY RESPONSIBILITY FOR THE FAILURE AND THE $3000 BILL FOR NEW PUMPS. BUT THAT IS NOT THE PURPOSE OF THIS LETTER. THE POINT OF THIS LETTER TO YOU IS TO MAKE SURE THAT COMPANY CHANGES ITS PRACTICE OF NOT CYCLING THE NEW BOOTS WITH THE AIRPLANE'S VACUUM SYS. I AM SURE MANY PLTS, ESPECIALLY IN THE WINTER, LEAVE AKRON IN CLOUDS AND ICING CONDITIONS, AND I AM SURE THAT VERY FEW OF THEM HAVE NEW VACUUM PUMPS. IF ANY OF THEM NEED TO USE THEIR NEW BOOTS AND HAVE A DUAL VACUUM FAILURE, THUS LOSING THEIR ALT INDICATOR AND DIRECTIONAL GYROSCOPE, THEY WOULD BE IN A PERILOUS POS TRYING TO FLY IN INST CONDITIONS WITH ONLY 'NEEDLE, BALL, AND AIRSPD. I TOLD THIS TO MR. X AND HE SAID THEY WOULD TAKE IT UNDER ADVISEMENT. FOR THE SAFETY OF MY FELLOW PLTS, I FEEL IT SHOULD BE MANDATORY FOR COMPANY AND ALL OTHER INSTALLER OF DEICING BOOTS, TO BE REQUIRED TO CYCLE NEW BOOT INSTALLATIONS WITH THE AIRPLANE'S VACUUM SYS BEFORE THE PLT IS ALLOWED TO FLY THE PLANE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT HIS MECH SAYS IT IS VERY UNUSUAL FOR BOTH VACUUM PUMPS TO FAIL AT THE SAME TIME. THAT IS WHY THERE ARE 2 PUMPS, SO 1 IS A BACK UP. THERE IS APPARENTLY NO WAY TO DETERMINE IF THERE IS ANY CONNECTION BTWN BOOT INSTALLATION AND THE PUMP FAILURES. THE COMPANY, IF THERE IS ANYTHING THEY DID WRONG, THEY WILL ACCEPT RESPONSIBILITY. THE RPTR PLANS TO INSTALL AN ELECTRICAL SYS TO REPLACE 1 OF THE VACUUM PUMPS ON HIS INSTS SO THAT HE HAS A MORE RELIABLE BACK UP. RPTRS PRIMARY CONCERN IS THAT THE WORD BE CIRCULATED REGARDING THE TESTING PROCS OF ANY COMPANY THAT INSTALLS DEICING EQUIP SO THE PLT CAN ASSURE THAT THE EQUIP IS TESTED USING THE ACFT VACUUM PUMPS, NOT JUST THE COMPANY AIR SOURCE. HE FEELS SURE THAT HAD HE BEEN IN IFR CONDITIONS HE WOULD NOT BE HERE TO TELL ABOUT IT. RPTR ALSO PLANS TO SEND A LETTER TO THE CESSNA TWIN OWNERS GROUP.

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.