Air carrier X excursion from assigned altitude. Altitude deviation.

Attributes
ACN	306410
Time
Date	199506
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : air
State Reference	OH
Altitude	msl bound lower : 9000 msl bound upper : 9000
Environment
Flight Conditions	IMC
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : slc
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	cruise other other
Route In Use	enroute : direct enroute airway : zob
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 230 flight time total : 11000 flight time type : 1000
ASRS Report	306410
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 220 flight time total : 21800 flight time type : 6200
ASRS Report	306168
Events
Anomaly	altitude deviation : excursion from assigned altitude other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

ZOB handling arrs into pittsburg got very busy due to peak arrival time and emergency handling of an aircraft landing in pit. Center started issuing holding instructions to aircraft landing in pit. We were given instructions to hold at 9000 ft as published over bellaire (air). After about 2 turns we were told to proceed from air to hlg and descend to 7000 ft. First officer (me) read back clearance to descend because captain was giving a brief PA explaining the unexpected hold. Captain did hear the ATC instructions and confirmed with me that the new altitude to descend to was 7000 ft. This was confirmed using standard company mandated altitude awareness procedures. While en route to hlg and established in the descent, ATC issued a speed reduction to us of 210 KTS. Captain responded and read back 'slowing to 210 KTS and descending to 7000 ft.' center asked captain to confirm this and he did. By this time we were at about 7800 ft. We were asked to say altitude and captain replied 'passing 7800 ft.' center instructed us to climb back up to 9000 ft which we did immediately. We were not aware of any conflict and received no TCASII warning. We were then vectored in sequence for landing at pit on runway 10R, without further incident or comment. I believe this situation developed due to aircraft saturation, marginal VFR WX conditions at the airport and the priority handling given to the aircraft experiencing the emergency. ATC commands were issued very rapidly to many aircraft which also contributed to this incident.

Original NASA ASRS Text

Title: ACR X EXCURSION FROM ASSIGNED ALT. ALTDEV.

Narrative: ZOB HANDLING ARRS INTO PITTSBURG GOT VERY BUSY DUE TO PEAK ARR TIME AND EMER HANDLING OF AN ACFT LNDG IN PIT. CTR STARTED ISSUING HOLDING INSTRUCTIONS TO ACFT LNDG IN PIT. WE WERE GIVEN INSTRUCTIONS TO HOLD AT 9000 FT AS PUBLISHED OVER BELLAIRE (AIR). AFTER ABOUT 2 TURNS WE WERE TOLD TO PROCEED FROM AIR TO HLG AND DSND TO 7000 FT. FO (ME) READ BACK CLRNC TO DSND BECAUSE CAPT WAS GIVING A BRIEF PA EXPLAINING THE UNEXPECTED HOLD. CAPT DID HEAR THE ATC INSTRUCTIONS AND CONFIRMED WITH ME THAT THE NEW ALT TO DSND TO WAS 7000 FT. THIS WAS CONFIRMED USING STANDARD COMPANY MANDATED ALT AWARENESS PROCS. WHILE ENRTE TO HLG AND ESTABLISHED IN THE DSCNT, ATC ISSUED A SPD REDUCTION TO US OF 210 KTS. CAPT RESPONDED AND READ BACK 'SLOWING TO 210 KTS AND DSNDING TO 7000 FT.' CTR ASKED CAPT TO CONFIRM THIS AND HE DID. BY THIS TIME WE WERE AT ABOUT 7800 FT. WE WERE ASKED TO SAY ALT AND CAPT REPLIED 'PASSING 7800 FT.' CTR INSTRUCTED US TO CLB BACK UP TO 9000 FT WHICH WE DID IMMEDIATELY. WE WERE NOT AWARE OF ANY CONFLICT AND RECEIVED NO TCASII WARNING. WE WERE THEN VECTORED IN SEQUENCE FOR LNDG AT PIT ON RWY 10R, WITHOUT FURTHER INCIDENT OR COMMENT. I BELIEVE THIS SIT DEVELOPED DUE TO ACFT SATURATION, MARGINAL VFR WX CONDITIONS AT THE ARPT AND THE PRIORITY HANDLING GIVEN TO THE ACFT EXPERIENCING THE EMER. ATC COMMANDS WERE ISSUED VERY RAPIDLY TO MANY ACFT WHICH ALSO CONTRIBUTED TO THIS INCIDENT.

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.