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Safety Recommendation Details

Safety Recommendation A-72-216
Details
Synopsis: ON AUGUST 24, 1972, THE NATIONAL TRANSPORTATION SAFETY BOARD COMPLETED A PUBLIC HEARING ON THE DELTA AIR LINES, INC., DC-9-14, N3305L, ACCIDENT WHICH OCCURRED AT FORT WORTH, TEXAS, ON MAY 30, 1972.
Recommendation: DEVELOP, ON AN EXPEDITED BASIS, NEW ATC SEPARATION STANDARDS WHICH CONSIDER THE RELATIVE SPAN LOADINGS OF THE VORTEX-GENERATING AIRCRAFT AND THE FOLLOWING AIRCRAFT UNDER METEOROLOGICAL CONDITIONS DEFINED AS BEING CONDUCIVE TO THE PERSISTENCE OF TRAILING VORTICES.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Aviation
Location: Fort Worth, TX, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: 79669
Accident Reports: Delta Air Lines, Inc., McDonnell Douglas DC-9-14, N3305L
Report #: AAR-73-03
Accident Date: 5/30/1972
Issue Date: 12/20/1972
Date Closed: 9/16/1976
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s):

Safety Recommendation History
From: NTSB
To: FAA
Date: 10/31/1974
Response: Closed--Acceptable Action.

From: FAA
To: NTSB
Date: 2/9/1973
Response: The data from flight tests indicates a relationship between the span ratio of the vortex generating aircraft and the magnitude of the effects experienced by the trailing aircraft. Specifically, short span aircraft can experience critical roll rates when encountering wing tip vortices. We do not believe that development of separation standards based on relative span loading and variable meteorological conditions is necessary at this time. However, as you know, we are continually reviewing and developing new standards wherever safety is involved. You are assured that if the data obtained in the November 1972 tests differs from that upon which the present criteria are based, we will refine the criteria.