Narrative:

The radar return showed a mass of colors 20 NM ahead that indicated an impending wild ride and it was starting to raise the hairs on the back of my neck. We were on a downwind vector for an ILS to runway xxr at 4000 ft and 170 KIAS. The evening inbound recovery was in progress that told me to expect the usual extended final. Although my better judgement suggested that I request a turn away from the storm; a couple of inputs encouraged me to push the envelope. ATC told company ahead that they could expect a turn prior to the storm; our TCAS showed at least 1 aircraft flying through the return and neither my first officer nor relief first officer voiced any concern. An early turn and no complaints from the aircraft flying through the storm nor my own crew gave me a sense that everything would be ok. When we realized that an early turn would not be offered; we were backed into the proverbial corner; with no place to go. As we entered the leading edge of the storm; things quickly went from bad to worse. We encountered moderate to severe turbulence; our airspeed increased from 170 KIAS to 230 KIAS and we developed a 1000 FPM rate of descent taking us to an altitude of almost 3600 ft. It was a very uncomfortable situation. We received a number of calls from ATC to maintain 170 KIAS and 4000 ft. The first officer valiantly fought to maintain control; but for a brief period of time we were along for the ride. After exiting the storm; we regained altitude and airspeed. The rest of the approach was uneventful. I conducted an extensive debrief with my crew and spent time talking with ATC about the situation. As expected it was a learning experience for everyone involved. ATC was very helpful. When they realized we were in a bad spot; they took the initiative to ensure that we had a clear flight path. We were not aware of any conflicts. On my drive home that evening; I was still kicking myself for making a very bad decision. Many times over my 30 yrs in the cockpit; I have freely asked for vectors or a couple of turns in holding in similar situations. I am still not sure why this evening was different. At the end of the day I 'again' relearned a very valuable aviation lesson. Next time I will use this experience to; hopefully; make the right decision. Supplemental information from acn 778594: the lesson I learned is to speak up early and loud when I see the ATC plan for vectors is not going to work with the WX I see on the radar. We all try to make it work and when the WX is bad; it's a real challenge to get everybody on the ground. It's a challenge when the WX is good. We should have entered holding out to the east till we could have been vectored to a shorter final -- further away from the WX. ATC should not have been vectoring traffic to the west of the field in such close proximity to the line of WX. They also would enhance crew awareness if they could project where they plan to turn the aircraft onto final. This single piece of information would have forced us to break out to the east to enter holding. We were dealing in an information vacuum; as it were; in determining how close to the diagonal line of weather that ATC intended to take us. I should have asked -- they should have offered!

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Original NASA ASRS Text

Title: MD11 ENTERED A TSTM WHILE BEING VECTORED FOR AN APCH. MODERATE TO SEVERE TURB WAS ENCOUNTERED WITH CONSIDERABLE ALT AND AIRSPEED FLUCTUATIONS.

Narrative: THE RADAR RETURN SHOWED A MASS OF COLORS 20 NM AHEAD THAT INDICATED AN IMPENDING WILD RIDE AND IT WAS STARTING TO RAISE THE HAIRS ON THE BACK OF MY NECK. WE WERE ON A DOWNWIND VECTOR FOR AN ILS TO RWY XXR AT 4000 FT AND 170 KIAS. THE EVENING INBOUND RECOVERY WAS IN PROGRESS THAT TOLD ME TO EXPECT THE USUAL EXTENDED FINAL. ALTHOUGH MY BETTER JUDGEMENT SUGGESTED THAT I REQUEST A TURN AWAY FROM THE STORM; A COUPLE OF INPUTS ENCOURAGED ME TO PUSH THE ENVELOPE. ATC TOLD COMPANY AHEAD THAT THEY COULD EXPECT A TURN PRIOR TO THE STORM; OUR TCAS SHOWED AT LEAST 1 ACFT FLYING THROUGH THE RETURN AND NEITHER MY FO NOR RELIEF FO VOICED ANY CONCERN. AN EARLY TURN AND NO COMPLAINTS FROM THE ACFT FLYING THROUGH THE STORM NOR MY OWN CREW GAVE ME A SENSE THAT EVERYTHING WOULD BE OK. WHEN WE REALIZED THAT AN EARLY TURN WOULD NOT BE OFFERED; WE WERE BACKED INTO THE PROVERBIAL CORNER; WITH NO PLACE TO GO. AS WE ENTERED THE LEADING EDGE OF THE STORM; THINGS QUICKLY WENT FROM BAD TO WORSE. WE ENCOUNTERED MODERATE TO SEVERE TURB; OUR AIRSPD INCREASED FROM 170 KIAS TO 230 KIAS AND WE DEVELOPED A 1000 FPM RATE OF DSCNT TAKING US TO AN ALT OF ALMOST 3600 FT. IT WAS A VERY UNCOMFORTABLE SITUATION. WE RECEIVED A NUMBER OF CALLS FROM ATC TO MAINTAIN 170 KIAS AND 4000 FT. THE FO VALIANTLY FOUGHT TO MAINTAIN CTL; BUT FOR A BRIEF PERIOD OF TIME WE WERE ALONG FOR THE RIDE. AFTER EXITING THE STORM; WE REGAINED ALT AND AIRSPD. THE REST OF THE APCH WAS UNEVENTFUL. I CONDUCTED AN EXTENSIVE DEBRIEF WITH MY CREW AND SPENT TIME TALKING WITH ATC ABOUT THE SITUATION. AS EXPECTED IT WAS A LEARNING EXPERIENCE FOR EVERYONE INVOLVED. ATC WAS VERY HELPFUL. WHEN THEY REALIZED WE WERE IN A BAD SPOT; THEY TOOK THE INITIATIVE TO ENSURE THAT WE HAD A CLR FLT PATH. WE WERE NOT AWARE OF ANY CONFLICTS. ON MY DRIVE HOME THAT EVENING; I WAS STILL KICKING MYSELF FOR MAKING A VERY BAD DECISION. MANY TIMES OVER MY 30 YRS IN THE COCKPIT; I HAVE FREELY ASKED FOR VECTORS OR A COUPLE OF TURNS IN HOLDING IN SIMILAR SITUATIONS. I AM STILL NOT SURE WHY THIS EVENING WAS DIFFERENT. AT THE END OF THE DAY I 'AGAIN' RELEARNED A VERY VALUABLE AVIATION LESSON. NEXT TIME I WILL USE THIS EXPERIENCE TO; HOPEFULLY; MAKE THE RIGHT DECISION. SUPPLEMENTAL INFO FROM ACN 778594: THE LESSON I LEARNED IS TO SPEAK UP EARLY AND LOUD WHEN I SEE THE ATC PLAN FOR VECTORS IS NOT GOING TO WORK WITH THE WX I SEE ON THE RADAR. WE ALL TRY TO MAKE IT WORK AND WHEN THE WX IS BAD; IT'S A REAL CHALLENGE TO GET EVERYBODY ON THE GND. IT'S A CHALLENGE WHEN THE WX IS GOOD. WE SHOULD HAVE ENTERED HOLDING OUT TO THE E TILL WE COULD HAVE BEEN VECTORED TO A SHORTER FINAL -- FURTHER AWAY FROM THE WX. ATC SHOULD NOT HAVE BEEN VECTORING TFC TO THE W OF THE FIELD IN SUCH CLOSE PROX TO THE LINE OF WX. THEY ALSO WOULD ENHANCE CREW AWARENESS IF THEY COULD PROJECT WHERE THEY PLAN TO TURN THE ACFT ONTO FINAL. THIS SINGLE PIECE OF INFO WOULD HAVE FORCED US TO BREAK OUT TO THE E TO ENTER HOLDING. WE WERE DEALING IN AN INFO VACUUM; AS IT WERE; IN DETERMINING HOW CLOSE TO THE DIAGONAL LINE OF WEATHER THAT ATC INTENDED TO TAKE US. I SHOULD HAVE ASKED -- THEY SHOULD HAVE OFFERED!

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.