C421 HAD LTSS FROM A CESSNA AT AN UNCTLED ARPT AT HDC.

Narrative

ON NOV/XA/99 AT ABOUT XA20; WE DEPARTED FROM SLIDELL; LA; ARPT (6R0) ON AN INST TRAINING FLT IN VFR CONDITIONS TO PREPARE THE PLT FOR A PART 135; AIR TAXI; CHK RIDE THE FOLLOWING DAY. I WAS ACTING AS SAFETY PLT/INSTRUCTOR AT THE TIME. CONDITIONS WERE SKY CLR; VISIBILITY APPROX 8 MI IN HAZE. SHORTLY AFTER DEP; THE PLT (WHO IS FILING A SEPARATE NASA RPT ON THIS SAME SIT) CLBED TO 3500 FT AND PROCEEDED TOWARD HAMMOND; LA; ARPT (0R9) WHERE WE INTENDED TO PERFORM MULTIPLE INST APCHS. IN THE CLB; THE PLT CONTACTED NEW ORLEANS APCH CTL AND ADVISED THE CTLR OF OUR INTENTIONS. WE WERE GIVEN A SQUAWK AND CLRED DIRECT HAMMOND VOR WITH INSTRUCTIONS TO REMAIN VFR. APPROX 1/2 WAY TO HAMMOND; I RESTR THE PLT'S OUTSIDE VISIBILITY (SIMULATED IFR) BY PLACING AN IFR ENRTE CHART ACROSS THE PLT'S SIDE OF THE FRONT WINDSCREEN. WE ARRIVED AT HAMMOND AND COMMENCED WITH OUR TRAINING APCHS. WE WERE IN CONTINUAL CONTACT WITH NEW ORLEANS APCH CTL ON FREQ 119.3 AND DUTIFULLY BROADCAST ON THE HAMMOND ADVISORY FREQ (122.9) AS DIRECTED BY APCH EACH TIME WE WERE NEARING THE CONCLUSION OF AN APCH MANEUVER. EACH TIME A MISSED APCH WAS EXECUTED AND WE RETURNED TO APCH FREQ; THE #2 COMS RADIO WAS PLACED ON THE ADVISORY FREQ AND ITS SELECTOR PLACED IN THE 'PHONE' POS SO THAT LCL TFC COULD BE MONITORED; AS WELL AS APCH. WE HAD BEEN IN THE LCL AREA FOR SOME TIME AND WERE CONCLUDING PERHAPS OUR 4TH OR 5TH APCH; WHICH IN THIS INSTANCE WAS AN ILS TO RWY 18; CONDUCTED WITH A SIMULATED FAILURE OF 1 ENG. AS HAD BEEN THE NORM; WHEN INSTRUCTED TO CHANGE TO ADVISORY FREQ; THE PLT DID SO AND ANNOUNCED THAT WE WERE INBOUND FOR THE ILS RWY 18 AT HAMMOND. NO RADIO TFC WAS HEARD AND NO TFC WAS IMMEDIATELY OBSERVED AS THE APCH COMMENCED AND CONTINUED. AT DECISION HT (244 FT) I INSTRUCTED THE PLT TO INITIATE A MISSED APCH. AS HE WAS INITIATING THE SINGLE ENG MISSED APCH; I OBSERVED AT APPROX OUR 10:30 - 11 O'CLOCK POS; A SINGLE ENG; HIGH WING ACFT; BELIEVED TO BE A CESSNA; APCHING FROM OUR L (E); PERPENDICULAR TO OUR COURSE; AND TRAVELING W. THE ACFT WAS ABOVE US AND AHEAD OF US; NEAR THE MIDPOINT OF THE ARPT AND RWY 18. A VERY ROUGH ESTIMATE OF ITS ALT IS 500-600 FT ABOVE US; OR 750-800 FT (THE PATTERN ALT IS 800 FT AGL). SENSING THE POTENTIAL CONFLICT. I ANNOUNCED TO THE PLT THAT I HAD CTL OF THE ACFT; TOOK CTL; IMMEDIATELY STOPPED OUR CLB FROM THE DECISION HT; MAINTAINED LEVEL FLT AT OR NEAR THE DECISION HT AND PASSED EITHER BELOW OR SLIGHTLY TO THE REAR AND UNDERNEATH THE CESSNA. WE DID NOT HAVE TO TAKE EXTRAORDINARY EVASIVE ACTION NOR DID THE CESSNA WHICH CONTINUED IN STRAIGHT AND LEVEL FLT. VERT SEPARATION WAS ESTIMATED AT APPROX 500-600 FT. NO BROADCAST WAS HEARD NOR WAS ONE MADE BY US CONCERNING THE INCIDENT. AFTER THE UNEVENTFUL PASSAGE; CTL WAS RETURNED TO THE PLT WHO COMPLETED THE SINGLE ENG MISSED APCH; CLBING TO THE ASSIGNED ALT OF 2000 FT AND MAINTAINING RWY HDG AS APCH HAD INSTRUCTED. THE CESSNA PROCEEDED OFF TO THE W AS WE CLBED OUT TO THE S. IT IS UNKNOWN WHETHER THE CESSNA ENTERED THE PATTERN AND LANDED. APPROX 15-20 MINS LATER; AS WE WERE HOLDING OVERHEAD THE ARPT ON THE HAMMOND VOR AT 2000 FT; AN ACFT CAME ONTO THE APCH FREQ INQUIRING IF APCH WAS IN CONTACT WITH A TWIN CESSNA MANEUVERING OVER HAMMOND ARPT. APCH; OF COURSE; REPLIED IN THE AFFIRMATIVE THAT WE HAD BEEN OPERATING VFR AND THAT WE WERE CURRENTLY HOLDING ON THE VOR AT 2000 FT. THE PLT THEN ASKED APCH FOR OUR REGISTRATION NUMBER AND APCH ASKED IF HE HAD A COMPLAINT OF SOME SORT. HIS RESPONSE WAS THAT WE '...WERE NOT LISTENING TO THE LCL FREQ AND HAD NEARLY CAUSED A MIDAIR.' WHEN THE PLT CONCLUDED HIS INQUIRY; I WENT ON APCH FREQ AND CLRLY STATED WHAT APCH ALREADY KNEW; THAT WE HAD BEEN MONITORING THE LCL FREQ CONTINUALLY; HAD BEEN IN CONTINUOUS CONTACT WITH APCH; THAT WE HAD HEARD NO XMISSIONS INDICATING TFC AND THAT WE WISHED TO MEET WITH THE COMPLAINING PLT. APCH REPLIED THAT HE HAD LEFT THE AREA AND WAS 6 MI TO THE N. IN RETROSPECT; HAVING IMMEDIATELY AND VERY CRITICALLY DEBRIEFED THE SIT WITH THE PLT FOR WHOM I WAS ACTING AS SAFETY PLT; WE BELIEVE; TO THE BEST OF OUR COLLECTIVE KNOWLEDGE; THAT HE DID NOT FAIL TO CONTACT AND MONITOR THE ADVISORY FREQ WHEN SO ADVISED. WE HAVE AGREED ON THE BELOW POTENTIAL CONTRIBUTING FACTORS: 1) USE OF CHART TO COVER L HALF OF WINDSCREEN OBSTRUCTED SAFETY PLT'S VISION TO L SIDE (THAT OF APCHING ACFT). 2) INTENSITY OF PHYSICAL AND MENTAL DEMANDS/WORKLOAD ASSOCIATED WITH THE SINGLE ENG MISSED APCH AT LOW ALT POTENTIALLY AFFECTED THE ABILITY TO DIVIDE ATTN BTWN SAFE CONDUCT OF THE FLT AND SCANNING FOR TFC. 3) COMS FAILURE(S) OR BREAKDOWNS (?) IF ANY; IN FACT; OCCURRED ON OUR PART; THEY WOULD UNDOUBTEDLY BE DUE TO #2. 4) POSSIBLE FAILURE OF THE OTHER PARTY TO MONITOR THE ADVISORY FREQ AND EFFECTIVELY COMMUNICATE. 5) FAILURE OF OTHER PARTY TO EFFECTIVELY SEE AND AVOID; AS WELL AS FAILURE TO YIELD TO OUR ACFT WHICH WAS BOTH 'LNDG' AND AT A LOWER ALT.