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Air carrier medium large transport overshoots altitude on descent as flight crew is concerned with cabin pressure problem. Reporter cites a communication interference problem along with traffic report.
| Attributes | |
| ACN | 125807 |
| Time | |
| Date | 198910 |
| Day | Thu |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : zny |
| State Reference | NY |
| Altitude | msl bound lower : 14700 msl bound upper : 15000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zny |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | cruise other descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : flight engineer pilot : commercial pilot : atp |
| Experience | flight time last 90 days : 105 flight time total : 11000 flight time type : 105 |
| ASRS Report | 125807 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp pilot : commercial pilot : instrument pilot : private |
| Experience | flight time last 90 days : 150 flight time total : 3800 flight time type : 600 |
| ASRS Report | 125731 |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance non adherence : required legal separation |
| Independent Detector | other controllera other flight crewa |
| Resolutory Action | flight crew : overcame equipment problem flight crew : returned to intended course or assigned course other |
| Consequence | Other |
| Miss Distance | horizontal : 5000 vertical : 700 |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
In a descent from FL260 from btv to phl, passing through FL210 to FL190, we got a cabin altitude horn. Trying to control the cabin altitude we requested an immediate descent to a lower altitude. We received 15000'. We then went on O2 and tried to establish communication, but weren't sure if we were getting through to ATC. We were given traffic at 10 O'clock position and 14000', and we said we were 'looking.' by this time we had fixed the pressurization problem and were finishing up on the emergency checklist when the cabin attendant came in to see us on O2. She then dashed out of the cockpit. My earpiece cord got tangled in the O2 cord and was being a pain, and I was still trying to verify contact with ATC. In this confusion I inadvertently hit the autoplt disconnect button on the yoke. That was at approximately 16000'. Meanwhile we had spotted the traffic at 12 O'clock low, passing underneath, and reported it to center. Shortly after we saw this traffic, center said 'maintain 15000'.' when I looked we were passing through 14700' descending, and immediately pulled the aircraft back up to 15000'. Ps: when autoplt was disengaged, copilot immediately took over flying manually.
Original NASA ASRS Text
Title: ACR MLG OVERSHOOTS ALT ON DESCENT AS FLT CREW IS CONCERNED WITH CABIN PRESSURE PROBLEM. REPORTER CITES A COM INTERFERENCE PROBLEM ALONG WITH TRAFFIC REPORT.
Narrative: IN A DSCNT FROM FL260 FROM BTV TO PHL, PASSING THROUGH FL210 TO FL190, WE GOT A CABIN ALT HORN. TRYING TO CONTROL THE CABIN ALT WE REQUESTED AN IMMEDIATE DSCNT TO A LOWER ALT. WE RECEIVED 15000'. WE THEN WENT ON O2 AND TRIED TO ESTABLISH COM, BUT WEREN'T SURE IF WE WERE GETTING THROUGH TO ATC. WE WERE GIVEN TFC AT 10 O'CLOCK POS AND 14000', AND WE SAID WE WERE 'LOOKING.' BY THIS TIME WE HAD FIXED THE PRESSURIZATION PROB AND WERE FINISHING UP ON THE EMER CHKLIST WHEN THE CABIN ATTENDANT CAME IN TO SEE US ON O2. SHE THEN DASHED OUT OF THE COCKPIT. MY EARPIECE CORD GOT TANGLED IN THE O2 CORD AND WAS BEING A PAIN, AND I WAS STILL TRYING TO VERIFY CONTACT WITH ATC. IN THIS CONFUSION I INADVERTENTLY HIT THE AUTOPLT DISCONNECT BUTTON ON THE YOKE. THAT WAS AT APPROX 16000'. MEANWHILE WE HAD SPOTTED THE TFC AT 12 O'CLOCK LOW, PASSING UNDERNEATH, AND RPTED IT TO CENTER. SHORTLY AFTER WE SAW THIS TFC, CENTER SAID 'MAINTAIN 15000'.' WHEN I LOOKED WE WERE PASSING THROUGH 14700' DSNDING, AND IMMEDIATELY PULLED THE ACFT BACK UP TO 15000'. PS: WHEN AUTOPLT WAS DISENGAGED, COPLT IMMEDIATELY TOOK OVER FLYING MANUALLY.
Data retrieved from NASA's ASRS site as of August 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.