Air carrier crew concerned that they may have crossed an approach fix 1000 ft too low at mia, fl.

Attributes
ACN	469949
Time
Date	200004
Day	Tue
Place
Locale Reference	airport : mia.airport
State Reference	FL
Altitude	msl bound lower : 4000 msl bound upper : 2000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : mia.tracon
Operator	common carrier : air carrier
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 27r other
Flight Phase	descent : approach
Route In Use	approach : instrument precision
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : mia.tracon
Operator	common carrier : air carrier
Make Model Name	Saab-Scania Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 27r
Flight Phase	descent : approach
Route In Use	approach : instrument precision
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : multi engine
ASRS Report	469949
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	469950
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa other flight crewb
Resolutory Action	none taken : anomaly accepted
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

A flight from tpa-mia approximately XA00, clear and 10 DME. Being vectored behind an air carrier saab for an ILS approach to mia runway 27R. On base leg in a descent for 3000 ft, we were given approach clearance and told to cross basho at 3000 ft, I believe. Noticed basho not on our displays. I found it on the approach plate and said we could identify it by 10.9 DME. Captain added basho to our approach on the FMC. After the distraction, we could not remember if we had been cleared to cross basho at 2000 ft or 3000 ft. Captain thought 2000 ft, I thought 3000 ft. I think we settled on 2000 ft, picked up the glide path and VASI's, switched to tower, and didn't think anything more about it. Today, I was thinking about it and cannot recall if we continued our descent to 2000 ft or stopped at 3000 ft. This was the 4TH leg of a very long day (8 hour flight time, 12 hours on duty). We were both pretty tired, and it is possible that we made a mistake on the altitude. Supplemental information from acn 469950: next day, discussion with my first officer on this prompted the decision to file this report. This was the 4TH of a 4 leg day after being awake 15 hours. It is possible a mistake was made on the altitude. I honestly don't know and am not able to recall the events with more detail. Tower did not question our altitude. It is possible we were cleared to 2000 ft and went there. Or we could have gone to 2000 ft when cleared to 3000 ft. I just don't recall. What bothers me is I do remember the first officer questioning the altitude and that I confirmed what I understood to be correct. I thought all was understood. I did not just check with ATC, which is what I would normally do any time there is a question about a clearance. I have to wonder how much the long day could have factored into all this. Frankly, I am surprised at my lack of recall of the events but find myself still tired after a night's rest.

Original NASA ASRS Text

Title: ACR CREW CONCERNED THAT THEY MAY HAVE CROSSED AN APCH FIX 1000 FT TOO LOW AT MIA, FL.

Narrative: A FLT FROM TPA-MIA APPROX XA00, CLR AND 10 DME. BEING VECTORED BEHIND AN ACR SAAB FOR AN ILS APCH TO MIA RWY 27R. ON BASE LEG IN A DSCNT FOR 3000 FT, WE WERE GIVEN APCH CLRNC AND TOLD TO CROSS BASHO AT 3000 FT, I BELIEVE. NOTICED BASHO NOT ON OUR DISPLAYS. I FOUND IT ON THE APCH PLATE AND SAID WE COULD IDENT IT BY 10.9 DME. CAPT ADDED BASHO TO OUR APCH ON THE FMC. AFTER THE DISTR, WE COULD NOT REMEMBER IF WE HAD BEEN CLRED TO CROSS BASHO AT 2000 FT OR 3000 FT. CAPT THOUGHT 2000 FT, I THOUGHT 3000 FT. I THINK WE SETTLED ON 2000 FT, PICKED UP THE GLIDE PATH AND VASI'S, SWITCHED TO TWR, AND DIDN'T THINK ANYTHING MORE ABOUT IT. TODAY, I WAS THINKING ABOUT IT AND CANNOT RECALL IF WE CONTINUED OUR DSCNT TO 2000 FT OR STOPPED AT 3000 FT. THIS WAS THE 4TH LEG OF A VERY LONG DAY (8 HR FLT TIME, 12 HRS ON DUTY). WE WERE BOTH PRETTY TIRED, AND IT IS POSSIBLE THAT WE MADE A MISTAKE ON THE ALT. SUPPLEMENTAL INFO FROM ACN 469950: NEXT DAY, DISCUSSION WITH MY FO ON THIS PROMPTED THE DECISION TO FILE THIS RPT. THIS WAS THE 4TH OF A 4 LEG DAY AFTER BEING AWAKE 15 HRS. IT IS POSSIBLE A MISTAKE WAS MADE ON THE ALT. I HONESTLY DON'T KNOW AND AM NOT ABLE TO RECALL THE EVENTS WITH MORE DETAIL. TWR DID NOT QUESTION OUR ALT. IT IS POSSIBLE WE WERE CLRED TO 2000 FT AND WENT THERE. OR WE COULD HAVE GONE TO 2000 FT WHEN CLRED TO 3000 FT. I JUST DON'T RECALL. WHAT BOTHERS ME IS I DO REMEMBER THE FO QUESTIONING THE ALT AND THAT I CONFIRMED WHAT I UNDERSTOOD TO BE CORRECT. I THOUGHT ALL WAS UNDERSTOOD. I DID NOT JUST CHK WITH ATC, WHICH IS WHAT I WOULD NORMALLY DO ANY TIME THERE IS A QUESTION ABOUT A CLRNC. I HAVE TO WONDER HOW MUCH THE LONG DAY COULD HAVE FACTORED INTO ALL THIS. FRANKLY, I AM SURPRISED AT MY LACK OF RECALL OF THE EVENTS BUT FIND MYSELF STILL TIRED AFTER A NIGHT'S REST.

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.