Service difficulty report · Throttle Body · Diamon DA20C1

Difficulty date
July 13, 2016
Submitted
July 15, 2016
Operation
General aviation
Aircraft
N973DA
Make and model
Diamon DA20C1
Aircraft serial
CO483
Aircraft time
4,825 hours
Engine
Cont IO240B
Engine time
883 hours
Propeller
Snsnch W69EK63
Part
Throttle Body
Part number
R6538981A19
Part serial
151A638R
Condition
Failed
Location
Engine
Part time
190 hours
Stage of operation
NR
How discovered
O
Nature of condition
O
Precautionary procedure
O

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

PREMATURE FAILURE OF THE THROTTLE BODY HAS BEEN NOTED. THIS SPECIFIC THROTTLE BODY FAILED AT 190.5 HRS AND HAS A SERVICE LIFE OF 2200 HOURS. DEFECTS IN THE THROTTLE BODY ARE EVIDENT BY CYCLING THE THROTTLE BODY ARM AND FEELING A GRINDING ATTRIBUTE. FURTHER EVIDENCE OF FAILURE IS THE INABILITY TO CORRECTLY ADJUST THE IDLE MIXTURE RISE. TRENDS AND ANALYSIS SHOW A CONSISTENT RECURRING PREMATURE FAILURE OF ALL THROTTLE BODIES WITH SERVICE LIFE'S BETWEEN 50-200 HOURS. THE SAFETY CONCERN REQUIRING ATTENTION IS THAT IF THE THROTTLE BODY FAILS DURING FLIGHT, WHICH MEANS ENOUGH WEAR FROM BRASS AND STEEL CONTAMINATION BECOME GRINDING, IN THE IDLE SETTING THE ENGINE COULD BECOME OVER RICHENED AND SUBSEQUENTLY FLOOD THE CYLINDERS WITH EXCESSIVE FUEL, RESULTING IN ENGINE FAILURE. THIS CONDITION COULD BE DETRIMENTAL AS IT COULD LEAD TO AN ACFT ACCIDENT OR INCIDENT. THE RECOMMENDATION TO CORRECT THIS DEFICIENCY IS FOR ENGINE MFG TO IDENTIFY THE REASON OF SUCH CONSTANT PREMATURE FAILURE AND RECOMMEND A SOLUTION TO CORRECT THE DEFICIENCY IN ORDER FOR THE THROTTLE BODY TO REACH SERVICE LIFE LIMITS.

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