B200 flight crew experienced a left bleed air failure and subsequent pressurization issues. Upon ini...

Attributes
ACN	787389
Time
Date	200805
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : cid.airport
State Reference	IA
Altitude	msl bound lower : 14000 msl bound upper : 27000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zau.artcc artcc : zzz.artcc
Make Model Name	Super King Air 200 HDC
Operating Under FAR Part	Part 91
Flight Phase	cruise : level descent : intermediate altitude
Flight Plan	IFR
Person 1
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 52 flight time total : 3695 flight time type : 37
ASRS Report	787389
Person 2
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 110 flight time total : 4150 flight time type : 330
ASRS Report	787497
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : master caution other flight crewa other flight crewb
Resolutory Action	flight crew : overcame equipment problem
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

Flight was being operated under far part 91 with 2 pilots and 6 passenger. As the aircraft was leveling at the final cruise altitude of FL270; the master warning light illuminated along with the left bleed air fail light on the annunciator panel. The cabin altitude indicated 5000 ft. Prior to placing the left bleed air valve in the 'environmental off' position; in accordance with the checklist; the pilots discussed the possible need to descend if the remaining bleed air was insufficient to maintain cabin pressurization. When the left bleed air valve was closed; the copilot noticed an immediate 4000 FPM climb on the cabin vertical speed indicator. The pilots requested an immediate descent from ZAU and were cleared to FL240. The PIC started a 3000 FPM descent to FL240 and the copilot requested a further descent. ZAU issued a frequency change to another ZAU controller and the PIC thought he also cleared the aircraft to FL190. The PIC; believing the aircraft was cleared to FL190; continued the descent. The copilot checked in with ZAU passing FL237 descending to FL190. The new controller did not indicate that the aircraft was not cleared to FL190; but did ask the copilot to confirm descending to FL190. The copilot confirmed the aircraft was in the descent to FL190 and due to a pressurization issue a further descent was needed. The controller then issued a clearance for a descent to 14000 ft and a 20 degree left heading for the descent. Passing through approximately 16000 ft; the cabin altitude rate of climb slowed and eventually started to descend. The aircraft leveled off at 14000 ft; the cabin altitude descended to and remained steady at 9000 ft. At this point the pilots asked for a climb to 15000 ft in order to be correct for direction of flight. The cabin altitude remained steady at 10000 ft for the remainder of the flight and flight proceeded to the destination uneventfully.

Original NASA ASRS Text

Title: B200 FLT CREW EXPERIENCED A L BLEED AIR FAILURE AND SUBSEQUENT PRESSURIZATION ISSUES. UPON INITIATING AN AGGRESSIVE DESCENT THEY QUESTION WHETHER THEY HAD RECEIVED THE CLEARANCE TO DESCEND OR IF THEIR ACTIONS WERE PREMATURE.

Narrative: FLT WAS BEING OPERATED UNDER FAR PART 91 WITH 2 PLTS AND 6 PAX. AS THE ACFT WAS LEVELING AT THE FINAL CRUISE ALT OF FL270; THE MASTER WARNING LIGHT ILLUMINATED ALONG WITH THE L BLEED AIR FAIL LIGHT ON THE ANNUNCIATOR PANEL. THE CABIN ALT INDICATED 5000 FT. PRIOR TO PLACING THE L BLEED AIR VALVE IN THE 'ENVIRONMENTAL OFF' POS; IN ACCORDANCE WITH THE CHKLIST; THE PLTS DISCUSSED THE POSSIBLE NEED TO DSND IF THE REMAINING BLEED AIR WAS INSUFFICIENT TO MAINTAIN CABIN PRESSURIZATION. WHEN THE L BLEED AIR VALVE WAS CLOSED; THE COPLT NOTICED AN IMMEDIATE 4000 FPM CLB ON THE CABIN VERT SPD INDICATOR. THE PLTS REQUESTED AN IMMEDIATE DSCNT FROM ZAU AND WERE CLRED TO FL240. THE PIC STARTED A 3000 FPM DSCNT TO FL240 AND THE COPLT REQUESTED A FURTHER DSCNT. ZAU ISSUED A FREQ CHANGE TO ANOTHER ZAU CTLR AND THE PIC THOUGHT HE ALSO CLRED THE ACFT TO FL190. THE PIC; BELIEVING THE ACFT WAS CLRED TO FL190; CONTINUED THE DSCNT. THE COPLT CHKED IN WITH ZAU PASSING FL237 DSNDING TO FL190. THE NEW CTLR DID NOT INDICATE THAT THE ACFT WAS NOT CLRED TO FL190; BUT DID ASK THE COPLT TO CONFIRM DSNDING TO FL190. THE COPLT CONFIRMED THE ACFT WAS IN THE DSCNT TO FL190 AND DUE TO A PRESSURIZATION ISSUE A FURTHER DSCNT WAS NEEDED. THE CTLR THEN ISSUED A CLRNC FOR A DSCNT TO 14000 FT AND A 20 DEG L HDG FOR THE DSCNT. PASSING THROUGH APPROX 16000 FT; THE CABIN ALT RATE OF CLB SLOWED AND EVENTUALLY STARTED TO DSND. THE ACFT LEVELED OFF AT 14000 FT; THE CABIN ALT DSNDED TO AND REMAINED STEADY AT 9000 FT. AT THIS POINT THE PLTS ASKED FOR A CLB TO 15000 FT IN ORDER TO BE CORRECT FOR DIRECTION OF FLT. THE CABIN ALT REMAINED STEADY AT 10000 FT FOR THE REMAINDER OF THE FLT AND FLT PROCEEDED TO THE DEST UNEVENTFULLY.

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.

B200 flight crew experienced a left bleed air failure and subsequent pressurization issues. Upon initiating an aggressive descent they question whether they had received the clearance to descend or if their actions were premature.