June 2002 - American Bonanza Society

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Bonanza & DebonairENGINE FAILURESBY THOMAS P TURNER, CLEVELAND, TENNESSEEKent Ewing, BPPP vice president, makes a regular presentationat BPPP training weekends. Using infonmationfrom AOPA Air Safety Foundation, Kent compiled a listof engine-failure accidents in the Bonanza andDebonair-Models 33, 3S and 36.Kent's slant, like that of almost all persons involved inrelating aircraft accident records, is th at merely knowing anhistorical accident trend exists may prompt pilots to take stepsto stop the trend,The study Kent quotes is getting old. AOPA'sBonanza/Debonair Accident Review was published in early1994, and its data is even older than that, derived fromNational Transportation Safety Board accident reports fromthe years 1982 through 1989,Knowing the data was aging, and wanting a more completepicture of the nature of Bonanza/Debonair engine fa ilureaccidents, Kent needed to research more recent mishap evaluations.I was honored that he asked me to help him, and happythat the power of the Internet makes such research far easierthan it was even a few years ago,AOPKslmo~adon: 1982-1989Greatly abbreviated, Kent's presentation of engine failuresusing AOPA ASF infonmation comes down to these facts:523 NTSB-investigated accidents involved the 33/35/36.159 of those reported power loss as a contributing factor in themishaj>-a little less than one-third of all Bonanza/Debonaircrashes.The most common cause of power interruption was related tofuel. Nonmechanical interruptions of fuel contributed to 67total accidents, or 42 percent of all Bonanza/Debonair enginerelatedmishaps,Nonmechanical causes include fuel starvation, fuelexhaustion and fuel contamination.Starvation occurs when the tank in use runs out of fue land fuel is available in another tank, but-for whatever reason-the pilot does not or cannot get the engine restartedbefore impact. Exhaustion covers the classic "running out ofgas." Contaminates were not detected or fully drained by thepilot before flight.The "cause undetermined" category was the next most commoncause of engine failure, accounting for 34 of the accidentsor about 21 percent of all engine outages. The NTSBcou ld not identify any specific reason for the engine failure ,True catastrophic engine fa ilures such as "blown" cylinders,broken crankshafts and propeller damage contributed to 30Bonanza/Debonair accidents during the study period, roughly19 percent of all engine failures.Failures of the fuel system were cited in 16 mishaps, about 10percent of the engine-failure total.Oil system failures contributed 10 seven accidents, 4 percentof the engine outages,The remaining five engi ne·faiJure reports involved electricaland ignition system failures-magneto failures, and the unfortunateresults of bearing failure on gear-driven altemators,which in a worst-case event can cause crankshaft damage.As Kent sums it up, ''The bad news is that 159 (enginerelatedaccidents) eq uates to 30.4 percent of the total. Thegood news is that nearly half (42 percent) of those were preventableby the pilot-
Failures of the fuel system are still the founh most likelycause: 27 mishaps during the II-year 1990-2000 period. orabout II percent of the engine-failure tOlal.Oil system fa ilures contributed to II accidents, still roughly 4percent of the engine outages.There was on ly one engine· failure repon citing electrical orignition system failures in the years 1990 through 2000.Switching fuel tanks only al an altitude Ihal gives enough timefor a restan, and preferably over a landing site in case theengine fails.Running a fuel tank completely dry in night, which somepilOls like to do to eke maximum range from Ihe airplane. Doso only if you've already confirmed you have good, usablefuel available elsewhere in the airplane. and again at an altitudethat permits time for a restan and over a landing site ifthe restart is unsuccessful.Mixture leaning. It may be that many fuel starvation andexhaustion accidents result in pan from a pilot who Ihinkshe/she has a cenain amount of fuel on board, but does notbecause of the leaning technique used.Fuel monitoring using as many sources of information as pos·sible, including known fue l on board at engine stan, fuel bumX time, fuel gauges, more accurale fuel totalizers and theirGPS interfaces, glancing at the fuel caps in Ilight to detect anysiphoning from the tanks, and even the trim feel of an out·offuel·balanceairplane.Fuel discipline, modifying your plans to reflect your fuel statewhile you still have time to be only slightly inconvenienced.Emergency procedures. BPPP's edict to control the airplaneand then "switch tanks" at the first sign of an engine failureseems statistically to be your best course of action when facedwith a power interruption in night.To paraphrase BPPP's Kent Ewing, the bad news is that,over the last 19 years, 35 percent of all NTSB-investigatedBonanza/Debonair accidents were caused in pan by enginefailure. The good news is that in close to half of all those casesgood pilot technique quite likely could have prevented themishap. Given the amount of time the neet spends in the aireach year, mechanical engine failu res are a rare eve nt indeed.Tom Turner writes, Jectures and teaches obout aviation safety and flying high-performanceairpfanes. He flies a 199858 Boron. You con reach fom at 423-336-2261, or tturner@wingnef.net.History remains the sameSo what does all this number-crunch ing tell us? Nineteenyears of investigative data, covering one-fi fth of the entire historyof powered. heavier-than-air flight tells us that enginefailure is a fairly rare event in Bonanzas and Debonairs. The1990-2000 record is virtually identical to the 1982-1989 AirSafety Foundation repon.ConSistently, there have been about one and a half enginerelated33/35/36 mishaps per month. In the largest ponion ofthose instances, the power interruption could likely have beenavoided if the pilot had properly checked the fuel before takeoff,and exercised good fuel management in flight.It's also interesting that there is lillie statistical evidenceth at the oft·reponed manufacturing quality control issues surroundingour aircraft engi nes has affected accident rates.Maybe the engines aren't really any more fragile than theywere in the past. Perhaps we're looking more closely duringinspections and finding problems sooner, or the repetitiveservice bulletins and Airwonhiness Directives really havehelped us avoid more tragic results.We have better all-cylinder monitoring systems now, andas a whole are better educated on engine operation and monitoring.Can it be we are doing a better job of running and troubleshootingour engines? Maybe we' re flying a lot less nowand the level accident trend is misleading.It 's hard to draw any definitive conclusions without a preciseaccounting of the actual number of hours flown each year,or a list of the number of cracks that were fixed,valves that were ground back into spec, or cylinders2002 BPPP SCHEDULEthat were replaced before they caused aInitial/Recurrent Phase at all tocations.mechanical failure in flight. We can say, though, Bonanzas/Barons/Travel Airs at all locations. Subject to change.that you can avoid the causes of nearly half of allengine failures by carefully evaluating your personalDATE LOCATION PHASEapproach to:June 28-30 Spokane. Washington Initial/RecurrentPrellight planning, taking into account additionalfuel reserves for flying into headwinds, inSeptember &8 Manchester, New Hampshire Initial/Recurrentinstrument conditions and/or at night.September 27-29 Fresno. CaliforniaInitial/RecurrentPreflight inspections, especialty checking fuel Oelober 18·20 Little Rock. Arkansas Initial/Recurrentlevels and tank ve nts, and straining contaminationfrom the tanks.November 8-10 Norfolk. Virginia Initial/RecurrentFuel tank use, including taking off and landingCoclcplt Companion course ovailob4e at all Iocahons.using main, not auxiliary fuel tanks; selectingCALL THE BPPP REGISTRAnON OFFICEthe fullest tank for takeoff long before takingto make arrangements 970-377·1877 or fox 970-337-1512.the runway; and switChing to the fullest tank forlanding well above pattern altitude (to assure A SAFE PILOT IS ALWAYS LEARNINGtime to restan the engine if necessary).ABS June 2002Page 7309
Page 3: N1397ZRichard BarnettWaldron, Arkan
Page 10 and 11: External power plugMichael WardWapp
Page 12 and 13: fuel selector valve itself (rather
Page 14 and 15: BONRNZR OF THE MONTHcomilllled from
Page 18 and 19: Scenario IThe first and biggest cha
Page 20 and 21: the $2,000 device as well. Between
Page 22 and 23: We graduated from the Guide Dogs of
Page 24 and 25: ABS President shares his memoriesRe
Page 26 and 27: BY STE VE ZELLER, ALPHARETIA, GEORG
Page 28 and 29: CylindersBY LEW GAGESa l finally br
Page 30 and 31: 820sh Formation Flying ClinicNot co
Page 32 and 33: CommunicationsBY JIM HUGHESBack in
Page 34 and 35: Two incidents at Washington Nationa
Page 36 and 37: HypertensionBY JOHN D. HASTINGS. M.
Page 39 and 40: Spring checkoutBY JOHN ALLENThose o
Page 41 and 42: Bonanza wing over the Grand Canyon.
Page 43 and 44: Web: www.strikefinder.comE-mail: in

June 2002 - American Bonanza Society

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