Altitude deviation.

Attributes
ACN	174522
Time
Date	199104
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : mia
State Reference	FL
Altitude	msl bound lower : 7500 msl bound upper : 8000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : mia
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other cruise other descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 5500 flight time type : 2500
ASRS Report	174522
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : undershoot inflight encounter : weather non adherence : clearance other anomaly other
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

I was the copilot, PNF, en route from lga to mia. While inbound to biscayne on the honda arrival at 9000 ft, I believe someone on the approach frequency (mia) had a stuck microphone and it was almost impossible to read approach. I was searching for another frequency, and at the same time trying to adjust the radar, as we were heading toward a trw cell. I then was barely able to discern approach control giving out a new frequency to all aircraft on the stuck microphone frequency. They gave us a 230 degree heading change to descent to 8000 ft and a change of frequency. I read it back, heading, altitude and frequency, and put it on the altitude alerter and HSI heading bug. I was then preoccupied with a cell that we were running into and we were getting bounced around. I was attempting to contact approach and asking for vector north to avoid the cell and then simultaneously the captain and I noticed we had dropped below 8000 ft, down to about 7500 ft. At this time approach told us to level off at 8000 ft. The problem was a preoccupation with the trw cell, the lost communications (the captain did not hear the controller) and the difficulty in reestablishing communications. I did not hear the audio or see the altitude alerter light.

Original NASA ASRS Text

Title: ALT DEVIATION.

Narrative: I WAS THE COPLT, PNF, ENRTE FROM LGA TO MIA. WHILE INBND TO BISCAYNE ON THE HONDA ARR AT 9000 FT, I BELIEVE SOMEONE ON THE APCH FREQ (MIA) HAD A STUCK MIC AND IT WAS ALMOST IMPOSSIBLE TO READ APCH. I WAS SEARCHING FOR ANOTHER FREQ, AND AT THE SAME TIME TRYING TO ADJUST THE RADAR, AS WE WERE HDG TOWARD A TRW CELL. I THEN WAS BARELY ABLE TO DISCERN APCH CTL GIVING OUT A NEW FREQ TO ALL ACFT ON THE STUCK MIC FREQ. THEY GAVE US A 230 DEG HDG CHANGE TO DSNT TO 8000 FT AND A CHANGE OF FREQ. I READ IT BACK, HDG, ALT AND FREQ, AND PUT IT ON THE ALT ALERTER AND HSI HDG BUG. I WAS THEN PREOCCUPIED WITH A CELL THAT WE WERE RUNNING INTO AND WE WERE GETTING BOUNCED AROUND. I WAS ATTEMPTING TO CONTACT APCH AND ASKING FOR VECTOR N TO AVOID THE CELL AND THEN SIMULTANEOUSLY THE CAPT AND I NOTICED WE HAD DROPPED BELOW 8000 FT, DOWN TO ABOUT 7500 FT. AT THIS TIME APCH TOLD US TO LEVEL OFF AT 8000 FT. THE PROB WAS A PREOCCUPATION WITH THE TRW CELL, THE LOST COMS (THE CAPT DID NOT HEAR THE CTLR) AND THE DIFFICULTY IN REESTABLISHING COMS. I DID NOT HEAR THE AUDIO OR SEE THE ALT ALERTER LIGHT.

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.