Air carrier X non adherence to ATC clearance. Descent to wrong altitude. Pilot deviation.

Attributes
ACN	174487
Time
Date	199104
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sju
State Reference	PR
Altitude	msl bound lower : 3000 msl bound upper : 5000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sju
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller radar : 10
ASRS Report	174487
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 225 flight time total : 6800 flight time type : 1800
ASRS Report	174616
Events
Anomaly	altitude deviation : overshoot non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	controller : issued new clearance flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I issued air carrier X 5000'. I issued air carrier X a right turn and observed the aircraft at 3200' descending in a 4400' MVA. I asked him his altitude and flight conditions and he stated he was IMC climbing due to an emergency terrain alert. I advised him to maintain 4400' and last assigned altitude was 5000'. He replied he read back 3000' twice. I advised him I did not receive the readback. Supplemental information from acn 174616: on approach to sju, we were being vectored by sju approach. We were in VFR conditions with clouds in front of us building over the mountains. Following a clearance to fly heading 280 degrees and descend to 5000', we were given a clearance to FL250 degrees and descend to 3000'. We read back the clearance and complied. Upon leveling at 3000' we were asked our altitude and reported level 3000'. We could see we were close to the mountains and then went into the clouds. At this point the GPWS went off with a terrain warning and we commenced a climb to 4000'. Approach asked our altitude again and we informed him of our actions to comply with the GPWS warning. He then stated he had only cleared us to descend to 5000'. At this time only one runway (8) was in use at sju. This presented a different workload to controllers as all commuter traffic was now being sequenced in with turbo jet arrival. It is not unusual to be given a clearance to 3000' on a downwind leg south of the airport. However, on this morning, I think while the controller gave us a descent he was used to giving, his traffic pattern was strung out more than normal. This caused us to go further south and west of the field than was normal and thus got us nearer the mountains.

Original NASA ASRS Text

Title: ACR X NON ADHERENCE TO ATC CLRNC. DESCENT TO WRONG ALT. PLT DEVIATION.

Narrative: I ISSUED ACR X 5000'. I ISSUED ACR X A RIGHT TURN AND OBSERVED THE ACFT AT 3200' DSNDING IN A 4400' MVA. I ASKED HIM HIS ALT AND FLT CONDITIONS AND HE STATED HE WAS IMC CLBING DUE TO AN EMER TERRAIN ALERT. I ADVISED HIM TO MAINTAIN 4400' AND LAST ASSIGNED ALT WAS 5000'. HE REPLIED HE READ BACK 3000' TWICE. I ADVISED HIM I DID NOT RECEIVE THE READBACK. SUPPLEMENTAL INFO FROM ACN 174616: ON APCH TO SJU, WE WERE BEING VECTORED BY SJU APCH. WE WERE IN VFR CONDITIONS WITH CLOUDS IN FRONT OF US BUILDING OVER THE MOUNTAINS. FOLLOWING A CLRNC TO FLY HDG 280 DEGS AND DSND TO 5000', WE WERE GIVEN A CLRNC TO FL250 DEGS AND DSND TO 3000'. WE READ BACK THE CLRNC AND COMPLIED. UPON LEVELING AT 3000' WE WERE ASKED OUR ALT AND RPTED LEVEL 3000'. WE COULD SEE WE WERE CLOSE TO THE MOUNTAINS AND THEN WENT INTO THE CLOUDS. AT THIS POINT THE GPWS WENT OFF WITH A TERRAIN WARNING AND WE COMMENCED A CLB TO 4000'. APCH ASKED OUR ALT AGAIN AND WE INFORMED HIM OF OUR ACTIONS TO COMPLY WITH THE GPWS WARNING. HE THEN STATED HE HAD ONLY CLRED US TO DSND TO 5000'. AT THIS TIME ONLY ONE RWY (8) WAS IN USE AT SJU. THIS PRESENTED A DIFFERENT WORKLOAD TO CTLRS AS ALL COMMUTER TFC WAS NOW BEING SEQUENCED IN WITH TURBO JET ARR. IT IS NOT UNUSUAL TO BE GIVEN A CLRNC TO 3000' ON A DOWNWIND LEG S OF THE ARPT. HOWEVER, ON THIS MORNING, I THINK WHILE THE CTLR GAVE US A DSNT HE WAS USED TO GIVING, HIS TFC PATTERN WAS STRUNG OUT MORE THAN NORMAL. THIS CAUSED US TO GO FURTHER S AND W OF THE FIELD THAN WAS NORMAL AND THUS GOT US NEARER THE MOUNTAINS.

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.