Page:CAB Accident Report, Piedmont Airlines Flight 349.pdf/8

 that faulty operatlon of ground nav1gatlonal and 1nstrument approach fac1lit1es caused or contrlbuted to the erroneous fllghtpath. This effort 1ncluded exhaustlve fllght and ground checks. The company and the Alr Carrler Branch of the FAA made several lnSpectlon fllghts, each nelng 1ts reSpectlve alrcraft. In addltlon, the Flight Inspection Branch of the FAA made evaluatlons cf the alrway and approach feellltles nelng spec1f1c pro- cedures and an alrcraft equlpped for the purPOSe. ThlS work revealed normal operatlon of the feellltles.

As part of thls phase the Board called upon the Federal Communicatlons Comm1ss1on to a551st. hhth epe01al equlpment and quallfled personnel the FCC team made a comprehen31ve 1nvest1gatlon coverlng a w1de range of con51dera— tlons relatlve to the performance, rellablllty, and 1nstallat10n of the homer beacons. Included were a search.for an unauthorlzed homer rumored to be 1n operatlon, an investlgatlon of electronic equlpment used by local manufactur- ers, and an evaluatlon of Slgnal strength w1th1n the operatlonal range re- qulrements spec1f1ed for the homer beacons.

Thls phase of the 1nvest1gatlon revealed no condltlon wnlch would 1mpa1r fllght conformlty along V-lhO or the executlon of a normal 1nstru- ment approach on the homer facllltles.

As prev1ousLy descrlbed, the airborne nav1gatlonal equlpment was determlned by physlcal ev1dence to have been properly tuned for an 1nstru— ment approach utlllzlng the ADF equipment on whlch the Charlottesv1lle approach was based. Because of thls 1t was of prlmary concern to the 1nves- tlgatlon whether or not the.ADF cockplt presentatlon was accurate. Most 1mpcrtant in this determinatlon were the peeltlons of the ADF loops relatlve to the crash headlng and locatlon. The extended.bear1ngs of the red and green ADF loop peeltlons passed nearly through the locatlon of the respectlve homer beacon to whlch each was tuned. Also, the angle formed between the bearlngs subtended an are at the homers equal to the dlstance between them. The Board does not belleve these loop peeltlons to be a matter of c01nC1dence but rather dlreot evldence the ADF's were functlonlng normally at the tlme of the acoldent. Furthermore, the elapsed tlme between reportlng Rochelle to the crash apparently exceeded the normal elapsed tlme from Rochelle to the 1nhound headlng of the procedure turn by several mlnutes. Bellev1ng the fllght operated 1n 1nstrument weather condltlons and made the flnal turn abeam of the procedure turn area, 1t 1s probable the turn was started wath reference to the ADF 1nd1catlons. The Board comelders 1t 1mprobable that the ADF presentation would be accurate in show1ng the alrcraft abeam of the fac111t1es and 1naccurate shortly'before this 1nd1catlon. It 15 equally 1mprobable that such 1naccuracy would be followed by an accurate presentatlon at the tlme the crash occurred.

Based on the work performed and the ev1dence found, 1t 15 the oplnlon of the Board that this accldert occurred for Operatlonal reasons. Consequently, the Board sought a determinatlon 1n tnls area whlch would aCCOunt for the

llghtpath of the aircraft oelng parallel to, but 8 to ll miles west of, the proper trace. It sought a Sltuatlon whacn could develop easrly and, because 1t 15 probable that Captaln Lavrlnc was flylng, one wrlch escaped observation by Copllot Haley. It also sought a eltuatlcn 1n Wthh the precarlous lateral error would not be readlly detested as such by either pilot. Because of a number of unxncwn elements and the 1nnerent 1ntang1bles of the operatlonal