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Captain of air carrier light transport aircraft with a pressurization problem descended below assigned altitude due to misinterpreting a heading change for an altitude assignment. In addition, did not adhere to new heading clearance.
| Attributes | |
| ACN | 212179 |
| Time | |
| Date | 199206 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : gee |
| State Reference | NY |
| Altitude | msl bound lower : 20000 msl bound upper : 24000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob |
| Operator | common carrier : air carrier |
| Make Model Name | Light Transport, Low Wing, 2 Turboprop Eng |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 200 |
| ASRS Report | 212179 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Experience | flight time last 90 days : 210 flight time total : 2800 |
| ASRS Report | 212394 |
| Events | |
| Anomaly | aircraft equipment problem : critical aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance other spatial deviation |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | none taken : detected after the fact |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
On flight xyz from syr to cle at FL240, first officer lost transmission capability with headset. We had to remove headsets to communicate with each other. Several mins later, forward door light map 'door' light illuminated also received 'door' oral warning. Noticed pressurization fluctuations. Notified ATC that we needed to descend to 10000 ft as a precautionary measure. Referenced quick reference handbook (QRH) for forward door light illuminated. Followed the procedures per QRH. Had flight attendant situation down and turned on fasten seatbelt sign. ATC stated to expect descent momentarily at this time, expecting the descent, ATC notified us to turn to 200. With the problem at hand, fluctuation in pressurization, and lack of headsets, crew's hearing was impaired. Flight crew, expecting the descent and misinterp of ATC instructions, descended to FL200. ATC asked if we were encountering any problems. We advised ATC that we were taking precautionary measures. ATC instructed us to descend to FL180 and switched us over to the next ATC frequency. On next, ATC frequency, we were descended to 10000 ft where first officer visually checked to make sure the door was aligned and properly sealed. First officer verified door was sealed and proceeded to cle. During the entire time, we took the most prudent course of action to ensure safety of flight. Recommendation: ATC should require full readback from crew for better clarification. Crew should verify between each other on ATC instructions.
Original NASA ASRS Text
Title: CAPT OF ACR LTT ACFT WITH A PRESSURIZATION PROBLEM DSNDED BELOW ASSIGNED ALT DUE TO MISINTERPRETING A HDG CHANGE FOR AN ALT ASSIGNMENT. IN ADDITION, DID NOT ADHERE TO NEW HDG CLRNC.
Narrative: ON FLT XYZ FROM SYR TO CLE AT FL240, FO LOST XMISSION CAPABILITY WITH HEADSET. WE HAD TO REMOVE HEADSETS TO COMMUNICATE WITH EACH OTHER. SEVERAL MINS LATER, FORWARD DOOR LIGHT MAP 'DOOR' LIGHT ILLUMINATED ALSO RECEIVED 'DOOR' ORAL WARNING. NOTICED PRESSURIZATION FLUCTUATIONS. NOTIFIED ATC THAT WE NEEDED TO DSND TO 10000 FT AS A PRECAUTIONARY MEASURE. REFED QUICK REF HANDBOOK (QRH) FOR FORWARD DOOR LIGHT ILLUMINATED. FOLLOWED THE PROCS PER QRH. HAD FLT ATTENDANT SIT DOWN AND TURNED ON FASTEN SEATBELT SIGN. ATC STATED TO EXPECT DSCNT MOMENTARILY AT THIS TIME, EXPECTING THE DSCNT, ATC NOTIFIED US TO TURN TO 200. WITH THE PROBLEM AT HAND, FLUCTUATION IN PRESSURIZATION, AND LACK OF HEADSETS, CREW'S HEARING WAS IMPAIRED. FLT CREW, EXPECTING THE DSCNT AND MISINTERP OF ATC INSTRUCTIONS, DSNDED TO FL200. ATC ASKED IF WE WERE ENCOUNTERING ANY PROBLEMS. WE ADVISED ATC THAT WE WERE TAKING PRECAUTIONARY MEASURES. ATC INSTRUCTED US TO DSND TO FL180 AND SWITCHED US OVER TO THE NEXT ATC FREQ. ON NEXT, ATC FREQ, WE WERE DSNDED TO 10000 FT WHERE FO VISUALLY CHKED TO MAKE SURE THE DOOR WAS ALIGNED AND PROPERLY SEALED. FO VERIFIED DOOR WAS SEALED AND PROCEEDED TO CLE. DURING THE ENTIRE TIME, WE TOOK THE MOST PRUDENT COURSE OF ACTION TO ENSURE SAFETY OF FLT. RECOMMENDATION: ATC SHOULD REQUIRE FULL READBACK FROM CREW FOR BETTER CLARIFICATION. CREW SHOULD VERIFY BTWN EACH OTHER ON ATC INSTRUCTIONS.
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.