Narrative:

Was dispatched from boston to montreal, quebec, canada with multiple maintenance 'carry-overs' including (1) pitch access 'porpoising' on both automatic pilots (renders category 2 and category 3 approachs unavailable to flight crew) and (2) altitude select arming 'intermittently' inoperative. Flight began a 'VNAV' descent to arrival over nabie intersection at 210 KTS airspeed at 8000 ft MSL. The first officer was the PF. As flight was cleared out of cruise altitude to a lower altitude, 'altitude arm' would not arm after several attempts (this terminated the planned VNAV descent requiring the descent to be flown non-automatic). 'Vertical speed' mode of the automatic flight system was selected and additional attempts were made to arm altitude select. Altitude would not arm but 'captured' the existing flight altitude and the autoplt leveled-off the aircraft. Additional attempts were made to re-establish descent and 'arm' the altitude with continual altitude 'captures' at intermediate altitudes. It was then discovered through montreal dorval ATIS that localizer back course runway 6R was in use and WX was 400 ft overcast, 2 mi visibility with light snow (icing conditions were encountered throughout the descent). As a result of maintenance problems with the autoflt system whereas the aircraft kept leveling-off at undesired/unselected altitudes, the flight was required to make an increasingly high rate of descent (to comply with altitudes and speeds required) without altitude-arming capability. Additionally, neither captain (checked out on the airplane for only 4 months and not in possession of the current approach plate), or the first officer had been into the airport for many years. As the flight was vectored onto final high and fast (without the altitude arm and both autoplts deficiencies), and to an altitude of 2000 ft MSL, crew 'got behind' on their duties and aircraft was positioned high for the turn-on. One last attempt to arm altitude 'mismatched' both pilots' flight directors and disengaged autoplt to 'control wheel steering.' both flight directors and their selected modes had to be turned-off completely, aircraft flown manually during the interim, and turned back on with all flight modes re-selected. When flight modes were re-selected on the avionics flight control system panel, 'localizer' was selected on the navigation panel in haste (and in error) for the back course approach. Autoplt was re-engaged simultaneously. Autoplt entered a steep-banked turn to the left to try to capture the localizer in the reverse direction ('heading' mode should have been selected and localizer not armed). Due to these many aircraft problems, the flight deviated from its course. The first officer disconnected the autoplt and attempted to re-establish the approach. The captain asked approach control for a vector to re- intercept the back course final approach and was given a heading of 090 degrees. At this point the first officer did not like the situation of multiple problems and distrs and decided to miss the approach. During pull-up, altitude arm did not operate and the aircraft climbed to 4000 ft. The first officer and the captain conferred and decided to take some time and get vectors for the ILS to runway 6L. Flight was re-vectored to the ILS runway 6L approach and landing was made without problems. Chain of events: multiple maintenance deferrals of the autoflt/autoplt system, a captain new to the aircraft without the current approach pilot (costing valuable additional time to brief the approach), an unfamiliar airport with a seldom-performed approach type, and a tired crew all contributed to a string of distrs, and unusual sits that led up to a potentially dangerous situation. The corrective action was the decision to go around and re-set up for a more familiar type of approach (ILS) while taking into account the maintenance deficiencies of the aircraft. Even though corrective action was made, it was not before the flight deviated from course on the intermediate-to-final approach segment and incurred an altitude deviation during missed approach. Incidentally, approach control asked 'why did you climb?' and the captain responded 'we did not like the approach.' approach control said 'very well' and vectored the flight back to the ILS runway 6L without further comment.

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Original NASA ASRS Text

Title: WDB ACR FLT IN WILD RIDE DURING APCH ATTEMPT AT YUL IAP LOC BACK COURSE APCH. FOREIGN AIRSPACE.

Narrative: WAS DISPATCHED FROM BOSTON TO MONTREAL, QUEBEC, CANADA WITH MULTIPLE MAINT 'CARRY-OVERS' INCLUDING (1) PITCH ACCESS 'PORPOISING' ON BOTH AUTO PILOTS (RENDERS CATEGORY 2 AND CATEGORY 3 APCHS UNAVAILABLE TO FLC) AND (2) ALTITUDE SELECT ARMING 'INTERMITTENTLY' INOP. FLT BEGAN A 'VNAV' DSCNT TO ARR OVER NABIE INTXN AT 210 KTS AIRSPD AT 8000 FT MSL. THE FO WAS THE PF. AS FLT WAS CLRED OUT OF CRUISE ALT TO A LOWER ALT, 'ALT ARM' WOULD NOT ARM AFTER SEVERAL ATTEMPTS (THIS TERMINATED THE PLANNED VNAV DSCNT REQUIRING THE DSCNT TO BE FLOWN NON-AUTOMATIC). 'VERTICAL SPD' MODE OF THE AUTO FLT SYS WAS SELECTED AND ADDITIONAL ATTEMPTS WERE MADE TO ARM ALT SELECT. ALT WOULD NOT ARM BUT 'CAPTURED' THE EXISTING FLT ALT AND THE AUTOPLT LEVELED-OFF THE ACFT. ADDITIONAL ATTEMPTS WERE MADE TO RE-ESTABLISH DSCNT AND 'ARM' THE ALT WITH CONTINUAL ALT 'CAPTURES' AT INTERMEDIATE ALTS. IT WAS THEN DISCOVERED THROUGH MONTREAL DORVAL ATIS THAT LOC BACK COURSE RWY 6R WAS IN USE AND WX WAS 400 FT OVERCAST, 2 MI VISIBILITY WITH LIGHT SNOW (ICING CONDITIONS WERE ENCOUNTERED THROUGHOUT THE DSCNT). AS A RESULT OF MAINT PROBS WITH THE AUTOFLT SYS WHEREAS THE ACFT KEPT LEVELING-OFF AT UNDESIRED/UNSELECTED ALTS, THE FLT WAS REQUIRED TO MAKE AN INCREASINGLY HIGH RATE OF DSCNT (TO COMPLY WITH ALTS AND SPDS REQUIRED) WITHOUT ALT-ARMING CAPABILITY. ADDITIONALLY, NEITHER CAPT (CHKED OUT ON THE AIRPLANE FOR ONLY 4 MONTHS AND NOT IN POSSESSION OF THE CURRENT APCH PLATE), OR THE FO HAD BEEN INTO THE ARPT FOR MANY YEARS. AS THE FLT WAS VECTORED ONTO FINAL HIGH AND FAST (WITHOUT THE ALT ARM AND BOTH AUTOPLTS DEFICIENCIES), AND TO AN ALT OF 2000 FT MSL, CREW 'GOT BEHIND' ON THEIR DUTIES AND ACFT WAS POSITIONED HIGH FOR THE TURN-ON. ONE LAST ATTEMPT TO ARM ALT 'MISMATCHED' BOTH PLTS' FLT DIRECTORS AND DISENGAGED AUTOPLT TO 'CTL WHEEL STEERING.' BOTH FLT DIRECTORS AND THEIR SELECTED MODES HAD TO BE TURNED-OFF COMPLETELY, ACFT FLOWN MANUALLY DURING THE INTERIM, AND TURNED BACK ON WITH ALL FLT MODES RE-SELECTED. WHEN FLT MODES WERE RE-SELECTED ON THE AVIONICS FLT CTL SYS PANEL, 'LOC' WAS SELECTED ON THE NAV PANEL IN HASTE (AND IN ERROR) FOR THE BACK COURSE APCH. AUTOPLT WAS RE-ENGAGED SIMULTANEOUSLY. AUTOPLT ENTERED A STEEP-BANKED TURN TO THE L TO TRY TO CAPTURE THE LOC IN THE REVERSE DIRECTION ('HDG' MODE SHOULD HAVE BEEN SELECTED AND LOC NOT ARMED). DUE TO THESE MANY ACFT PROBS, THE FLT DEVIATED FROM ITS COURSE. THE FO DISCONNECTED THE AUTOPLT AND ATTEMPTED TO RE-ESTABLISH THE APCH. THE CAPT ASKED APCH CTL FOR A VECTOR TO RE- INTERCEPT THE BACK COURSE FINAL APCH AND WAS GIVEN A HDG OF 090 DEGS. AT THIS POINT THE FO DID NOT LIKE THE SIT OF MULTIPLE PROBS AND DISTRS AND DECIDED TO MISS THE APCH. DURING PULL-UP, ALT ARM DID NOT OPERATE AND THE ACFT CLBED TO 4000 FT. THE FO AND THE CAPT CONFERRED AND DECIDED TO TAKE SOME TIME AND GET VECTORS FOR THE ILS TO RWY 6L. FLT WAS RE-VECTORED TO THE ILS RWY 6L APCH AND LNDG WAS MADE WITHOUT PROBS. CHAIN OF EVENTS: MULTIPLE MAINT DEFERRALS OF THE AUTOFLT/AUTOPLT SYS, A CAPT NEW TO THE ACFT WITHOUT THE CURRENT APCH PLT (COSTING VALUABLE ADDITIONAL TIME TO BRIEF THE APCH), AN UNFAMILIAR ARPT WITH A SELDOM-PERFORMED APCH TYPE, AND A TIRED CREW ALL CONTRIBUTED TO A STRING OF DISTRS, AND UNUSUAL SITS THAT LED UP TO A POTENTIALLY DANGEROUS SIT. THE CORRECTIVE ACTION WAS THE DECISION TO GAR AND RE-SET UP FOR A MORE FAMILIAR TYPE OF APCH (ILS) WHILE TAKING INTO ACCOUNT THE MAINT DEFICIENCIES OF THE ACFT. EVEN THOUGH CORRECTIVE ACTION WAS MADE, IT WAS NOT BEFORE THE FLT DEVIATED FROM COURSE ON THE INTERMEDIATE-TO-FINAL APCH SEGMENT AND INCURRED AN ALT DEV DURING MISSED APCH. INCIDENTALLY, APCH CTL ASKED 'WHY DID YOU CLB?' AND THE CAPT RESPONDED 'WE DID NOT LIKE THE APCH.' APCH CTL SAID 'VERY WELL' AND VECTORED THE FLT BACK TO THE ILS RWY 6L WITHOUT FURTHER COMMENT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.