Air carrier mdt altitude deviation excursion from clearance altitude on practice ASR approach to phl...

Attributes
ACN	188119
Time
Date	199108
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : phl
State Reference	PA
Altitude	msl bound lower : 1300 msl bound upper : 1800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : phl tower : jfk
Operator	common carrier : air carrier
Make Model Name	Medium Transport
Flight Phase	descent : approach descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 270 flight time total : 12000 flight time type : 3000
ASRS Report	188119
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : atp pilot : commercial
Experience	flight time last 90 days : 280 flight time total : 4000
ASRS Report	189007
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were on an ASR approach to runway 35 about 12 mi south of the phl airport. The controller came on and told us that the MDA was 540 ft. Both the first officer and myself misunderstood the statement and took this to be a clearance to descend to the MDA. Out of about 1300 ft the controller asked us what our altitude was. I figured something was wrong at that point and told controller we were descending to MDA. She told us that we were not authorized to descend yet and to climb back up to 1800 ft, and that we had misunderstood the statement. We immediately climbed back to 1800 ft. Human performance: the controller used the proper verbiage in advising us of the MDA. The problem was at our end. It would be helpful for us if the controller could make a statement after issuing the MDA to reaffirm the assigned altitude. In this instance if controller had said 'MDA is 540 ft, maintain 1800 ft for now' or something to that effect, it would have clarified to us that we were not to descend at that time.

Original NASA ASRS Text

Title: ACR MDT ALT DEV EXCURSION FROM CLRNC ALT ON PRACTICE ASR APCH TO PHL.

Narrative: WE WERE ON AN ASR APCH TO RWY 35 ABOUT 12 MI S OF THE PHL ARPT. THE CTLR CAME ON AND TOLD US THAT THE MDA WAS 540 FT. BOTH THE FO AND MYSELF MISUNDERSTOOD THE STATEMENT AND TOOK THIS TO BE A CLRNC TO DSND TO THE MDA. OUT OF ABOUT 1300 FT THE CTLR ASKED US WHAT OUR ALT WAS. I FIGURED SOMETHING WAS WRONG AT THAT POINT AND TOLD CTLR WE WERE DSNDING TO MDA. SHE TOLD US THAT WE WERE NOT AUTHORIZED TO DSND YET AND TO CLB BACK UP TO 1800 FT, AND THAT WE HAD MISUNDERSTOOD THE STATEMENT. WE IMMEDIATELY CLBED BACK TO 1800 FT. HUMAN PERFORMANCE: THE CTLR USED THE PROPER VERBIAGE IN ADVISING US OF THE MDA. THE PROBLEM WAS AT OUR END. IT WOULD BE HELPFUL FOR US IF THE CTLR COULD MAKE A STATEMENT AFTER ISSUING THE MDA TO REAFFIRM THE ASSIGNED ALT. IN THIS INSTANCE IF CTLR HAD SAID 'MDA IS 540 FT, MAINTAIN 1800 FT FOR NOW' OR SOMETHING TO THAT EFFECT, IT WOULD HAVE CLARIFIED TO US THAT WE WERE NOT TO DSND AT THAT TIME.

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.