TRACON controller described a go around evnt due to wake turbulence spacing listing wind factors; la...

Narrative:

While working a combined arrival and final position an A340 was given to me under the impression that the aircraft was in emergency status; at the time it was quite busy given the weather conditions and there was some difficult in identifying the conditions of the emergency. After vectoring the aircraft into the sequence the pilot requested several deviations around weather and was extremely slow to descend or reduce speed; showing no real indicators that it was in fact a serious emergency. Because of this he was quite high almost until I cleared him on the approach. The supervisor on duty had spoken to the pilot of the emergency aircraft and the situation was identified as the crew being close to the end of its duty time. The aircraft in front of the A340 was a B767 who had been slowed to final approach speed for the aircraft in front of him; this was reading 80 KTS over the ground; I didn't think much of it due to the extreme wind conditions that had been causing significant complexity the entire night; with a little under five miles between the two aircraft I slowed the aircraft to final approach speed from his previously assigned speed of 180 KTS and switched him to the tower believing that the speed reduction would hold the spacing. The aircraft showed no real speed reduction for several sweeps indicating 140 KTS over the ground until separation was lost and the tower pulled the aircraft out of the sequence. I don't know if this was a failure to slow in a timely manner by the pilot; or if the B767 simply had such a radically different final approach speed that I would have needed an additional 4-5 miles of buffer separation in order for the approach to work. If it is the case that the B767 had a final approach speed of roughly 110-120 KTS; something that is significantly slower than what we normally see out of the same aircraft at other times which usually is around 140-150; it would have been extremely beneficial for the pilot to have advised me that his speed was going to be that slow. We are used to seeing the B757 aircraft slow much more significantly; but the B767s usually perform similar to the other aircraft. With the weather conditions that night it was very difficult to discern what is the weather affecting the aircraft and something the pilot is doing.

Original NASA ASRS Text

Title: TRACON Controller described a go around evnt due to wake turbulence spacing listing wind factors; lack of information provided by the aircraft and a confused emergency declaration as contributing to the event.

Narrative: While working a combined arrival and final position an A340 was given to me under the impression that the aircraft was in emergency status; at the time it was quite busy given the weather conditions and there was some difficult in identifying the conditions of the emergency. After vectoring the aircraft into the sequence the pilot requested several deviations around weather and was extremely slow to descend or reduce speed; showing no real indicators that it was in fact a serious emergency. Because of this he was quite high almost until I cleared him on the approach. The supervisor on duty had spoken to the pilot of the emergency aircraft and the situation was identified as the crew being close to the end of its duty time. The aircraft in front of the A340 was a B767 who had been slowed to final approach speed for the aircraft in front of him; this was reading 80 KTS over the ground; I didn't think much of it due to the extreme wind conditions that had been causing significant complexity the entire night; with a little under five miles between the two aircraft I slowed the aircraft to final approach speed from his previously assigned speed of 180 KTS and switched him to the Tower believing that the speed reduction would hold the spacing. The aircraft showed no real speed reduction for several sweeps indicating 140 KTS over the ground until separation was lost and the Tower pulled the aircraft out of the sequence. I don't know if this was a failure to slow in a timely manner by the pilot; or if the B767 simply had such a radically different final approach speed that I would have needed an additional 4-5 miles of buffer separation in order for the approach to work. If it is the case that the B767 had a final approach speed of roughly 110-120 KTS; something that is significantly slower than what we normally see out of the same aircraft at other times which usually is around 140-150; it would have been extremely beneficial for the pilot to have advised me that his speed was going to be that slow. We are used to seeing the B757 aircraft slow much more significantly; but the B767s usually perform similar to the other aircraft. With the weather conditions that night it was very difficult to discern what is the weather affecting the aircraft and something the pilot is doing.

Data retrieved from NASA's ASRS site as of April 2012 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	947261
Time
Date	201004
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Night
Aircraft 1
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	A340
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Person 1
Function	Approach
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy

TRACON controller described a go around evnt due to wake turbulence spacing listing wind factors; lack of information provided by the aircraft and a confused emergency declaration as contributing to the event.