Narrative:

I flew and provided flight instruction in an unairworthy aircraft. The aircraft is a da-41; diamond twinstar 2.0; with a missing right propeller deice boot. It was discovered that a deice boot was missing from the right propeller. The airplane was grounded and sent to maintenance; where they glued another boot onto the propeller. 3 days later; I was flying the airplane when the newly attached boot departed the airplane in-flight. Evidently there was a time requirement for allowing the newly glued boot to dry; and I was not informed that the boot would take at least 48 hours to dry. No unusual vibrations or noises were noticed on the return flight. Upon landing and securing the aircraft; I contacted the chief flight instructor to inform him of the problem. He informed me that he believed the aircraft was still airworthy; as long as I didn't notice any issues with vibration. I informed him I did not detect any such issues and; therefore; I filled out an open squawk sheet; rendering the aircraft airworthy by deferring the maintenance issue; however; effectively grounding the airplane for flight into IMC and/or known or forecast icing conditions. I continued to operate the aircraft VFR within 50 NM for flight training purposes; as did other flight instructors I work with as well as a designated pilot examiner; who conducted a check ride in the aircraft. During the 16 days I flew the aircraft; I never noticed any vibration issues; neither did any of the other instructors who flew the aircraft. The aircraft was grounded; upon the suggestion that the aircraft might not be airworthy during an interview for a new chief flight instructor. Upon consultation of the type certificate for the aircraft; it was determined the aircraft was no longer airworthy; as it did not meet the specifications of its original type design. My reasoning for deferring this as a maintenance issue was based largely upon the advice of my immediate superior; the chief flight instructor. It was upon his recommendation that I continued to fly the aircraft; even though it was technically unairworthy. At the time; there were many back-to-back flts in the aircraft; and the amount of time required to let the boot dry would have meant grounding the aircraft for 48-72 hours. Of course; safety was always paramount; however; since the aircraft was believed to be airworthy; no rush was made to ground the aircraft for 2 days to do the repair. I recognize now that the decision to keep the airplane in service was not according to 91.213; and I am submitting this report on the basis of my understanding that I discovered after the fact that I flew an unairworthy aircraft for 16 days. Since I believed the aircraft was airworthy; I am just as much to blame as anyone else because I failed to check the type certificate as required by the regulations and relied upon a verbal justification from my chief flight instructor instead of checking myself. The aircraft has since been grounded and repaired. I believe this incident arose not because of neglect; but because of lack of a dedicated maintenance person and oversight into the procedures for open squawks. I feel I have been educated by this experience and now have a better understanding of 91.213. I was quick to assume that 91.205 covered me; when in fact I should have read 91.213 more carefully.

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Original NASA ASRS Text

Title: DA42 WAS REPEATEDLY OPERATED FOR FLT INSTRUCTION WITH A DEICING BOOT MISSING FROM A PROPELLER.

Narrative: I FLEW AND PROVIDED FLT INSTRUCTION IN AN UNAIRWORTHY ACFT. THE ACFT IS A DA-41; DIAMOND TWINSTAR 2.0; WITH A MISSING R PROP DEICE BOOT. IT WAS DISCOVERED THAT A DEICE BOOT WAS MISSING FROM THE R PROP. THE AIRPLANE WAS GNDED AND SENT TO MAINT; WHERE THEY GLUED ANOTHER BOOT ONTO THE PROP. 3 DAYS LATER; I WAS FLYING THE AIRPLANE WHEN THE NEWLY ATTACHED BOOT DEPARTED THE AIRPLANE INFLT. EVIDENTLY THERE WAS A TIME REQUIREMENT FOR ALLOWING THE NEWLY GLUED BOOT TO DRY; AND I WAS NOT INFORMED THAT THE BOOT WOULD TAKE AT LEAST 48 HRS TO DRY. NO UNUSUAL VIBRATIONS OR NOISES WERE NOTICED ON THE RETURN FLT. UPON LNDG AND SECURING THE ACFT; I CONTACTED THE CHIEF FLT INSTRUCTOR TO INFORM HIM OF THE PROB. HE INFORMED ME THAT HE BELIEVED THE ACFT WAS STILL AIRWORTHY; AS LONG AS I DIDN'T NOTICE ANY ISSUES WITH VIBRATION. I INFORMED HIM I DID NOT DETECT ANY SUCH ISSUES AND; THEREFORE; I FILLED OUT AN OPEN SQUAWK SHEET; RENDERING THE ACFT AIRWORTHY BY DEFERRING THE MAINT ISSUE; HOWEVER; EFFECTIVELY GNDING THE AIRPLANE FOR FLT INTO IMC AND/OR KNOWN OR FORECAST ICING CONDITIONS. I CONTINUED TO OPERATE THE ACFT VFR WITHIN 50 NM FOR FLT TRAINING PURPOSES; AS DID OTHER FLT INSTRUCTORS I WORK WITH AS WELL AS A DESIGNATED PLT EXAMINER; WHO CONDUCTED A CHK RIDE IN THE ACFT. DURING THE 16 DAYS I FLEW THE ACFT; I NEVER NOTICED ANY VIBRATION ISSUES; NEITHER DID ANY OF THE OTHER INSTRUCTORS WHO FLEW THE ACFT. THE ACFT WAS GNDED; UPON THE SUGGESTION THAT THE ACFT MIGHT NOT BE AIRWORTHY DURING AN INTERVIEW FOR A NEW CHIEF FLT INSTRUCTOR. UPON CONSULTATION OF THE TYPE CERTIFICATE FOR THE ACFT; IT WAS DETERMINED THE ACFT WAS NO LONGER AIRWORTHY; AS IT DID NOT MEET THE SPECS OF ITS ORIGINAL TYPE DESIGN. MY REASONING FOR DEFERRING THIS AS A MAINT ISSUE WAS BASED LARGELY UPON THE ADVICE OF MY IMMEDIATE SUPERIOR; THE CHIEF FLT INSTRUCTOR. IT WAS UPON HIS RECOMMENDATION THAT I CONTINUED TO FLY THE ACFT; EVEN THOUGH IT WAS TECHNICALLY UNAIRWORTHY. AT THE TIME; THERE WERE MANY BACK-TO-BACK FLTS IN THE ACFT; AND THE AMOUNT OF TIME REQUIRED TO LET THE BOOT DRY WOULD HAVE MEANT GNDING THE ACFT FOR 48-72 HRS. OF COURSE; SAFETY WAS ALWAYS PARAMOUNT; HOWEVER; SINCE THE ACFT WAS BELIEVED TO BE AIRWORTHY; NO RUSH WAS MADE TO GND THE ACFT FOR 2 DAYS TO DO THE REPAIR. I RECOGNIZE NOW THAT THE DECISION TO KEEP THE AIRPLANE IN SVC WAS NOT ACCORDING TO 91.213; AND I AM SUBMITTING THIS RPT ON THE BASIS OF MY UNDERSTANDING THAT I DISCOVERED AFTER THE FACT THAT I FLEW AN UNAIRWORTHY ACFT FOR 16 DAYS. SINCE I BELIEVED THE ACFT WAS AIRWORTHY; I AM JUST AS MUCH TO BLAME AS ANYONE ELSE BECAUSE I FAILED TO CHK THE TYPE CERTIFICATE AS REQUIRED BY THE REGS AND RELIED UPON A VERBAL JUSTIFICATION FROM MY CHIEF FLT INSTRUCTOR INSTEAD OF CHKING MYSELF. THE ACFT HAS SINCE BEEN GNDED AND REPAIRED. I BELIEVE THIS INCIDENT AROSE NOT BECAUSE OF NEGLECT; BUT BECAUSE OF LACK OF A DEDICATED MAINT PERSON AND OVERSIGHT INTO THE PROCS FOR OPEN SQUAWKS. I FEEL I HAVE BEEN EDUCATED BY THIS EXPERIENCE AND NOW HAVE A BETTER UNDERSTANDING OF 91.213. I WAS QUICK TO ASSUME THAT 91.205 COVERED ME; WHEN IN FACT I SHOULD HAVE READ 91.213 MORE CAREFULLY.

Data retrieved from NASA's ASRS site as of May 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.