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B757-200 flight crew is dispatched with right engine bleed on MEL requiring avoidance of icing conditions enroute but the weather does not cooperate.
| Attributes | |
| ACN | 786440 |
| Time | |
| Date | 200805 |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : zzz.artcc |
| State Reference | US |
| Altitude | msl single value : 35000 |
| Environment | |
| Flight Conditions | IMC |
| Aircraft 1 | |
| Controlling Facilities | artcc : zzz.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B757-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : intermediate altitude |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Experience | flight time last 90 days : 171 flight time total : 8000 flight time type : 1217 |
| ASRS Report | 786440 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Experience | flight time last 90 days : 180 flight time total : 15000 flight time type : 5200 |
| ASRS Report | 786444 |
| Events | |
| Anomaly | aircraft equipment problem : less severe inflight encounter : weather maintenance problem : non compliance with mel |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : declared emergency flight crew : overcame equipment problem |
| Supplementary | |
| Problem Areas | Company Flight Crew Human Performance Weather |
| Primary Problem | Weather |
Narrative:
Right engine bleed deferred prior to departure; due to hpsov fluctuating. Assured by dispatch that northern routing would keep us clear of WX; and allow descent east of the WX system without need of engine anti-ice (not available due to deferral). The undercast did not clear as forecast and left only 1 option: declaring an emergency and turning on the engine bleed in order to make the engine anti-ice available. After consulting with dispatch and maintenance and using our knowledge of the system; we declared the emergency; turned on the bleed and anti-ice; and commenced descent. Bleed pressure remained at a constant 25 psi and the anti-ice valve operated normally. At 17000 ft we turned the bleed back off; we declared the emergency over; and continued a normal arrival and landing at ZZZ. All remaining system operated normal at all times. Declaring the emergency was in our opinion; the only valid option that we had. The decision to go was based on the forecast provided and the radar and satellite pictures viewed prior to departure. Dispatch concurred on the routing and descent plan based on the WX and restrs on the MEL.
Original NASA ASRS Text
Title: B757-200 FLT CREW IS DISPATCHED WITH RIGHT ENG BLEED ON MEL REQUIRING AVOIDANCE OF ICING CONDITIONS ENROUTE BUT THE WEATHER DOES NOT COOPERATE.
Narrative: R ENG BLEED DEFERRED PRIOR TO DEP; DUE TO HPSOV FLUCTUATING. ASSURED BY DISPATCH THAT NORTHERN ROUTING WOULD KEEP US CLR OF WX; AND ALLOW DSCNT E OF THE WX SYS WITHOUT NEED OF ENG ANTI-ICE (NOT AVAILABLE DUE TO DEFERRAL). THE UNDERCAST DID NOT CLR AS FORECAST AND LEFT ONLY 1 OPTION: DECLARING AN EMER AND TURNING ON THE ENG BLEED IN ORDER TO MAKE THE ENG ANTI-ICE AVAILABLE. AFTER CONSULTING WITH DISPATCH AND MAINT AND USING OUR KNOWLEDGE OF THE SYS; WE DECLARED THE EMER; TURNED ON THE BLEED AND ANTI-ICE; AND COMMENCED DSCNT. BLEED PRESSURE REMAINED AT A CONSTANT 25 PSI AND THE ANTI-ICE VALVE OPERATED NORMALLY. AT 17000 FT WE TURNED THE BLEED BACK OFF; WE DECLARED THE EMER OVER; AND CONTINUED A NORMAL ARR AND LNDG AT ZZZ. ALL REMAINING SYS OPERATED NORMAL AT ALL TIMES. DECLARING THE EMER WAS IN OUR OPINION; THE ONLY VALID OPTION THAT WE HAD. THE DECISION TO GO WAS BASED ON THE FORECAST PROVIDED AND THE RADAR AND SATELLITE PICTURES VIEWED PRIOR TO DEP. DISPATCH CONCURRED ON THE ROUTING AND DSCNT PLAN BASED ON THE WX AND RESTRS ON THE MEL.
Data retrieved from NASA's ASRS site as of May 2009 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.