B737 flight crew plans landing wet runway with good braking action and tower reports fair breaking a...

Narrative:

Inbound mdw WX sheet and ATIS showed strong storms/showers in the chicago area. We checked also the field condition through ACARS: wet good on all surfaces. Aircraft were landing in front of us. We had to go around on our first approach (ILS runway 31C) at minimum. Tower asked us why and we answered that we could not see the runway at minimum. Shortly afterwards; while climbing out towards joliet (3000 ft; hold east); we heard tower stating the RVR was 2000 ft. Within one turn in holding the WX improved rapidly; rain stopped. We were vectored back for an ILS runway 31C. Among us were several other aircraft; some with low fuel condition. I picked up the new ATIS. The computer came up with only maximum braking not bracketed. I believe the stopping margin was around 1000 ft. We selected maximum autobrake and the final approach was normal and well stabilized. We saw the runway at least 5 mi out. Passing through 900-1000 ft the tower broadcasted that aircraft had reported the braking action to be wet fair. There was no time to rechk the landing data at that altitude. The captain (PF) decided to continue the approach to land. I did not want to start a discussion at that moment. I felt we should have gone around again; however; I assumed the relative big stopping margin for wet good would allow us to land safely. We landed safely; the aircraft was at a safe taxi speed well before the standard high speed turnoff runway 31C. At the gate I changed the data in the computer to wet fair to confirm our assessment had been correct. I was surprised to see that our stopping margin was -40 ft. Mdw should have changed the runway to runway 4R. This would have been the better runway for the existing wind conditions (slight headwind versus 3 KTS tailwind at runway 31C). They should have informed us earlier to be able to make a timely correct decision for our landing. It was too late to rechk the computer at this point of flight. We should have gone around. We should/could have checked the data for wet fair to be ready in case we received the runway condition report like we had this time.

Original NASA ASRS Text

Title: B737 FLT CREW PLANS LANDING WET RWY WITH GOOD BRAKING ACTION AND TOWER REPORTS FAIR BREAKING ACTION ON SHORT FINAL. FLT CREW LANDS UNEVENTFULLY.

Narrative: INBOUND MDW WX SHEET AND ATIS SHOWED STRONG STORMS/SHOWERS IN THE CHICAGO AREA. WE CHKED ALSO THE FIELD CONDITION THROUGH ACARS: WET GOOD ON ALL SURFACES. ACFT WERE LNDG IN FRONT OF US. WE HAD TO GO AROUND ON OUR FIRST APCH (ILS RWY 31C) AT MINIMUM. TWR ASKED US WHY AND WE ANSWERED THAT WE COULD NOT SEE THE RWY AT MINIMUM. SHORTLY AFTERWARDS; WHILE CLBING OUT TOWARDS JOLIET (3000 FT; HOLD E); WE HEARD TWR STATING THE RVR WAS 2000 FT. WITHIN ONE TURN IN HOLDING THE WX IMPROVED RAPIDLY; RAIN STOPPED. WE WERE VECTORED BACK FOR AN ILS RWY 31C. AMONG US WERE SEVERAL OTHER ACFT; SOME WITH LOW FUEL CONDITION. I PICKED UP THE NEW ATIS. THE COMPUTER CAME UP WITH ONLY MAX BRAKING NOT BRACKETED. I BELIEVE THE STOPPING MARGIN WAS AROUND 1000 FT. WE SELECTED MAX AUTOBRAKE AND THE FINAL APCH WAS NORMAL AND WELL STABILIZED. WE SAW THE RWY AT LEAST 5 MI OUT. PASSING THROUGH 900-1000 FT THE TWR BROADCASTED THAT ACFT HAD RPTED THE BRAKING ACTION TO BE WET FAIR. THERE WAS NO TIME TO RECHK THE LNDG DATA AT THAT ALT. THE CAPT (PF) DECIDED TO CONTINUE THE APCH TO LAND. I DID NOT WANT TO START A DISCUSSION AT THAT MOMENT. I FELT WE SHOULD HAVE GONE AROUND AGAIN; HOWEVER; I ASSUMED THE RELATIVE BIG STOPPING MARGIN FOR WET GOOD WOULD ALLOW US TO LAND SAFELY. WE LANDED SAFELY; THE ACFT WAS AT A SAFE TAXI SPD WELL BEFORE THE STANDARD HIGH SPD TURNOFF RWY 31C. AT THE GATE I CHANGED THE DATA IN THE COMPUTER TO WET FAIR TO CONFIRM OUR ASSESSMENT HAD BEEN CORRECT. I WAS SURPRISED TO SEE THAT OUR STOPPING MARGIN WAS -40 FT. MDW SHOULD HAVE CHANGED THE RWY TO RWY 4R. THIS WOULD HAVE BEEN THE BETTER RWY FOR THE EXISTING WIND CONDITIONS (SLIGHT HEADWIND VERSUS 3 KTS TAILWIND AT RWY 31C). THEY SHOULD HAVE INFORMED US EARLIER TO BE ABLE TO MAKE A TIMELY CORRECT DECISION FOR OUR LNDG. IT WAS TOO LATE TO RECHK THE COMPUTER AT THIS POINT OF FLT. WE SHOULD HAVE GONE AROUND. WE SHOULD/COULD HAVE CHKED THE DATA FOR WET FAIR TO BE READY IN CASE WE RECEIVED THE RWY CONDITION RPT LIKE WE HAD THIS TIME.

Data retrieved from NASA's ASRS site as of May 2009 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.

Attributes
ACN	789669
Time
Date	200806
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : mdw.airport
State Reference	IL
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Weather Elements	Thunderstorm Rain
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	landing : roll
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 273
ASRS Report	789669
Events
Anomaly	non adherence : company policies
Independent Detector	other flight crewa
Resolutory Action	flight crew : executed missed approach none taken : detected after the fact
Supplementary
Problem Areas	ATC Human Performance Airport Flight Crew Human Performance Weather
Primary Problem	Flight Crew Human Performance

B737 flight crew plans landing wet runway with good braking action and tower reports fair breaking action on short final. Flight crew lands uneventfully.