A11 controller voiced concern regarding the new optimal profile descent (opd) procedures recently im...

Narrative:

Both aircraft were flying the portj one arrival. The facility and regional management were advised at a users meeting; prior to implementation; that the variable altitudes on the arrival would allow for losses of separation due to varying strong winds aloft. It didn't take long to come to pass. The MD11; whose company isn't as concerned about turbulence; was about 5;000 ft lower and 60 KTS slower than the B737; whose company is very concerned about turbulence over turnagain arm east of anchorage. The aircraft were accepted from anchorage ARTCC with about 8 miles in-trail plus the overtake. The B737 was assigned interim altitudes in order to prevent a loss of separation. This procedure will not work safely with the optional altitudes at which aircraft can fly east of anchorage. Recommendation: prohibit the use of all optimal profile descent procedures (opd's) that involve anchorage TRACON- portj one; neell one; and kroto one; until the procedures can be safely implemented again at some time in the future.

Original NASA ASRS Text

Title: A11 Controller voiced concern regarding the new Optimal Profile Descent (OPD) procedures recently implemented noting the variable altitudes charted allow for overtake situations.

Narrative: Both aircraft were flying the PORTJ One Arrival. The facility and regional management were advised at a users meeting; prior to implementation; that the variable altitudes on the arrival would allow for losses of separation due to varying strong winds aloft. It didn't take long to come to pass. The MD11; whose company isn't as concerned about turbulence; was about 5;000 FT lower and 60 KTS slower than the B737; whose company is very concerned about turbulence over Turnagain Arm east of Anchorage. The aircraft were accepted from Anchorage ARTCC with about 8 miles in-trail plus the overtake. The B737 was assigned interim altitudes in order to prevent a loss of separation. This procedure will not work safely with the optional altitudes at which aircraft can fly east of Anchorage. Recommendation: prohibit the use of all Optimal Profile Descent Procedures (OPD's) that involve Anchorage TRACON- PORTJ One; NEELL One; and KROTO One; until the procedures can be safely implemented again at some time in the future.

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	911373
Time
Date	201009
Local Time Of Day	1201-1800
Place
Locale Reference	A11.TRACON
State Reference	AK
Aircraft 1
Make Model Name	MD-11
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR PORTJ ONE
Flight Plan	IFR
Aircraft 2
Make Model Name	B737-400
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR PORTJ ONE
Flight Plan	IFR
Person 1
Function	Approach Departure Handoff / Assist
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy

A11 controller voiced concern regarding the new optimal profile descent (opd) procedures recently implemented noting the variable altitudes charted allow for overtake situations.