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,Re1-7?-P2-TSF5Cr--4plicnir FvK'ii5377/t6Y-e'd 7/,/oP,.DOC ETEDUSNRC.-AFR-110142P03 JAN) 7 PM:fUSAF AIRCRAFToF-IE 0,i,,E-EiRRULEMAKINGS STAFFANDADJUDICATIONSACCIDENTINVESTIGATIONBOARD7 FEB 94F-16 AIRCRAFTSIN 90-0764138FG125FSINVESTIGATION OF FICERRICHAIDMPEDERSEN, LT COL,. USAFS"-.i.-,."- .r'- " -" .I . ""--"" , .-U ' -" .-AU:'-,-FOR. E-,;-l57817COPY-NUMBER.'OF.ScC VY-oa,

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2. SUMMARY OF FACTS:a. Histo ofFtint:at 0914 CST(1) Two F-16CG aircraft, call signs Tulsa 11 and 12, took off from Tulsa LAPMOA (TAB V(TAB Z-1). They were to conduct a Basic Fighter Maneuver (BFM) mission in the Riverspenienced an.x,Jment1). At approximately 0945 CST while setting up for the third engage(TAB J-5,stagnationandstallexplosion and severe engine and airframe vibrations, followed by an engineFor anthrust.useableregainandV-1). Ittempted two airstarts, but was unable to start the enginebladeturbinesLagefourthaoffractureunknown reason, the engine had experienced a high cycle fatigueVS-5,S-4,J-5,(TAB(LMturbinepressurebelow the blaik platform and subsequent damage to the 1). At approximately 0948 CST,on priate proprtyminimum recommended iection altitude (TAB A-2, N-1, V-I). The aircraft crailied120 NM southapprximatelyOK.,Sope,of(NM).northused for cattle grazing 1I'2 nautical milessoutheakt of Tulsa International Airport (lAP'(TAB P-2).property ,wasiiniThulsa,.OK (TAB A 2,; P72). 'Acual diamage to privatedataPtakfftume oC09 14pli.seventS( All following tines are based on-.Tulsa lbs recordedipto-tile c.SDThe,1). ,-AB AASeal DataR.corder (SDR)aircraftoad' m- a .recorded b(,the:-,, k '' :' f.-,.,--. ,. ,:ae nSDRdetuto-rmmPact7mntatuSsystcenmmdata,dtdith, and Digital Backup Unit data Aircraftq7icýdatatermination ARAA. .(ANG). I - he Te mission was scheduled as a 2 ship BFM 3 tor-aininjission iT benflsswn'lAW-MC[betv Fly'ing Training F-16hcs rnetepnssesshptak offswith'20, second-spacinr.vzsualandmaneuvcr,-Jqneheat-t-guns cine rackk--xerqisq,ýbotbeh.- nggemen,for recoyaIAPflw.to Tulsaandae returm Tutdsa12 was.:.:. ",. ,.- ,,- ,,landmg60NA:-."heare iaaeimdeyonUVim -Range -(BVR) 'BM,"Tub I AM':.- ",, . :.:, -,,-.,:: . ,57818by

*0c. Briefing and Prefliiht:(K-4). The preflight briefing began atBoth flight members reported adequate crew rest for the missionr n Emergency divert fields were specifically briefed.07'15 CST and was briefed in detail byg regulations (TAB V-2). Both members ofThe briefing covered all applicable items required by egeneral flow of the mission, and had nothethe flight indicated they clearly understood the objectives,preflightand beganquestions about the flight briefing. Both pilots arrived at their jets IAW briefed timesuneventful (TAB V-1, V-2).inspections. Preflight, start, taxi, marshaling and arming weret:d. FlitA t-flight plan (TAB K-4). At(1) Tulsa 11 flight was filed and cleared for the Zebra 4 stereowith 20 seconds spacing between aircraftapproximately 0914 CST, they accomplished single ship takeoffsaccomplishing air-to-air systems checks(TAB V-1, Z-l). They rejoined into a 2 ship formation whileplan terminated when entering theflightenroute to the working area. The outbound portion of the stereoRiver MOA (TAB V-1,V-2).one heat-to-guns exercise and two visual(2) Tulsa 11 flight completed a G-awareness maneuver,had some minor problems withf ir-to-air radar, butBFM engagements as briefed. second engagement, Tulsa I I and 12 split upthis had no effect on the overall mission conduct. After thesetup to a visual engagement Tulsa 11with approximately 35-40 NM separation for a one-v-one BVRwent to the northeast (TAB V-1).went to the southwest part of the River MOA and Tulsa 12severefirst indications of any problems were an explosion followed ame and engine va ons. The vibrations seemedinversely, the lower the RPM, the less severe.the higher the RPM, the more severe the vibrations andof engine RPK were so severe that it wasThe vibrations continued for the rest of the flight and regardlessV-1). At approximately 31 minutes afterdifficult to read the cockpit instruments at any time (TABstagnated. The fatigue fracture of a fourthtakeoff at 0944:52 CST, the aircraft engine stalled and thenand drag on the LPT which drives the enginestage turbine blade had resulted in the ensuing damage todisrupted airflow to the engine compressorfan. This produced drag on the engine fan which limited and" was noon, 2it"pointinlet, produchig-an engine stall and stagiation:-- From thislonger capable of producing useable thrust (TAB.J-5).t0e nearestt ituation,.4*simultane( ý'-Uiltrned towardna.yzd(4) As s6utlirsduthwest ,of leemegencyaifield f c :o (TABS:-I);. Gr yon was the s iecifllybriefed g,time-Ufthe emergency (TAB V?2) The airfield haFs a 9000-FTrimaway,(rAB AA-3Gryo t-dstaii .b.t9d-Jglidigwasouuytr-i -eihriiairfPeld s soas--hkneWii.IVproid asitac overonly uedliiiL'czvihan aIyture d southwestandKatdtu. i8000to rejoraob' .Baad-z -' o- -thi,o teF-6i,irifigtheno iibwasr .l., (SVO30F, level., flinhad-ecisea,et(i)aoeMean1;O7. -5. . V-I). -. . .(TAB -J-5;. .,.Average terrain. . . . . -. .airspeed,(KCAS),.calibratedand at 364-. knotslevel.(AGL)groundaboveBased on cockpit indications,elevation nca & stion was approximately 700 IFT MSL (TAB AA-5).,: t-Tror'- ,;f f j ,.);.,-begin tosew nted tol-and-at the nars suitableAying-,f that were thaisoxum r ableengi w-bad -Iready shdnto it wasthv--Altog mH- .OKsianilitianairpotiere s" """"44)e.ngine.wul.-1). Both airldswrless 'thaw350. I,'fctiong and i* rblemnect-on hoping.thedir.uk .ic-ietheapproxiitlA. .9.

0*@I*initially interpreted the engn 'malfunction as an engine rollbc pulehe throttle beaposition at 0945:21 (TAB J-5, V-i). Despite difficulty reading the engine instruments,soon no iced that engine RPM was decreasing and fan turbine inlet temperature (FTIT) was incresing,indications of an engine stagnation. In addition to the stagnationoelt.that the problem wasgiving*much worse due to the explosion and continuing vibrations. OTfilhen accomplished the emergencychecklist procedures which called for an engine shutdown to clear the stagnation and an airstart attempt(TAB V-i).began to execute the Critical Action Procedures LCAPs) for an engine airstart(6)laedto attempt a SECparameters and cockpit indications, currentonBasdAA-6).(TABis 0aestablishedandairstartspooldownwas 'flying atwhen attempting an airstart below 10,000 FT AGL (TAB AA-6).approximately 0,300 FT AGL at the time (TAB AA-I). di id not jettisonU empty centerline fuelfelt the weight and drag of the emptyconcentration on other airstart procEdures, 0tank due to.glide nor increasýeime aloft (TAB V-I). Atcenterline fu eltank would not appreciably affl:next moved the engine control0945:20 placed the throttle to off to clear the engine stagnation.*switch fr6m the PRI to the SEC position at 0945:28, which is confirmed by the SDR. At 0946:33,inpselected START 2 on the Jet Fuel Starter (JFS) to assist with the airstart. Approximately 1EoRnsecond prior to selecting JFS START 2, the SDR shows the engine control switch was placed back in PRI(TAB J-5, V-I). While working to maintain the recommended spooldown airspeed of 275 KCAS,noticed the engine RPM had decreased below the minimum recommended 25% RPM. According toat 0945:36testimony,'Jmmediately moved the throttle to IDLE at 18-20% RPM to initiate an airstart0(TAB JFTITC698andRPM17%at(TAB J-5, V-I). The SDR shows the throttle was advanced to idlewasthrottletheassoonasbegan5). Despite the lower than recommended 25% RPM, the llyadvanced from OFF to IDLE, appearing to progress0946:00, the JFS started running (TAB O-141:ýf(TAB J-5, V-I). At some time between 0945:33 andglide (TAB V-i).KCASntinued to m'tain2n70-290(7) The SDR indicates that the engine appeared to approach normal idle power indications, thenstalled a second time at 0946:45. At some time between 0946:30 and 0946:50, the throttle was advancedrecognized the second engine stall and stagnation. Althoughýquicklyto h4IL (TAB J-5)the attempt appeared to progress normallyfel* still had the samewengine instruments sproblemsbhad prior to initiating the first airstart due to the second stagnation and continuing severevibrations (TAB V-i):the throtte to OFF a(8) At 0947:05 and an estimated 5000 FT MSLJ4300 FT AG! oew as now, rnng,JFStheSinceAA-i)2:-J-5,(TABstagnationsecond timfe to attempt to clear the secondin order lRiassisted 'planned t6-o ioa'JFSdecerate ajdmore time. * does not-remember-what airspeedsiowedtoTA&V-i).,The SDR shows airspeed decreasing during this imewith-a last reco"deifspeedtoof 243 KCAS;4p&jviimatei)' 19 sei;nIs prioito ejec tion (TAB AA-1).Th Saatemen of.Damage210 KCAS (TAB P-2).ipctatayaircraft gonropl i estimatedPrivateinS.qwI-a-'-(9) Asrm ed o zno e theengine control switch ro vhinoicditwas alreaidy in PRI ff lected to continue hairstart ini Pr'uninbailuit Aitrie orecommended constrolhedout oftimne dad approde ang -the mintimu-tn a;successf(TAB .,V-i,. A -7).M was'skepticzal abu-airs'tart si-nce.the thteoD"1-57820--57820týattempt (TABV-iztLd-otcdnRat.mpr"vemeafter the ,"5J50 TALtjinitiate th'second ai aff atept,,(rAB.- -. AA-i).estimated 420nTestimoqny indicated that he thought he was higher at an estimated 7300 feet MSL (TABV-)Ij,,'p. 'had mad a conscious decision'to eject if(10) 'At 3300 FTr MSIJ2SOO FT AGL,engine -again tried to start, but stalledTheattempt.thisonthrustusableanythe engine did not produce*--.