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Safety Recommendation Details

Safety Recommendation A-06-040
Details
Synopsis: On August 13, 3004, about 0049 eastern daylight time, Air Tahoma, Inc., flight 185, a Convair 580, N586P, crashed about 1 mile south of Cincinnatimorthern Kentucky International Airport, Covington, Kentucky, while on approach to runway 36R. The first officer was killed, and the captain received minor injuries. The airplane was destroyed by impact forces. The flight was operating under the provisions of 14 Code of Federal Regzllations Part 121 as a cargo flight for DHL exrpess from Memphis International Airport. Memphis, Tennessee, to Covington. Visual meteorological conditions prevailed for the flight, which operated on an instrument flight rules flight plan.
Recommendation: TO THE FEDERAL AVIATION ADMINISTRATION: Require Convair 580 operators to set the left and right fuel boost pump output pressure settings on their airplanes to the same setting.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Alternate Action
Mode: Aviation
Location: Florence, KY, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA04MA068
Accident Reports: Crash During Approach to Landing, Air Tahoma, Inc., Flight 185, Convair 580, N586P
Report #: AAR-06-03
Accident Date: 8/13/2004
Issue Date: 5/17/2006
Date Closed: 2/16/2011
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Alternate Action)
Keyword(s): Flightcrew, Procedures, Procedures: Flightcrew

Safety Recommendation History
From: NTSB
To: FAA
Date: 2/16/2011
Response: On April 3, 2007, the FAA issued Special Airworthiness Information Bulletin (SAIB) NE-07-24, which recommends that Convair 580 operators use identical fuel boost pump pressures in both tanks. Although this document does not contain the recommend3ed requirement, we note that the FAA surveyed U.S. Convair 580 operators to confirm that they had taken the recommended action and that the operators of the 14 active aircraft have either provided the SAIB and the safety alert for operators to their aircrews or have updated training materials and procedures in accordance with the recommendations. Because the FAA was able to confirm that the entire active U.S. Convair 580 fleet has configured both boost pumps as recommended, we believe that the FAA’s actions constitute an acceptable alternate means of addressing the recommendation. According, Safety Recommendation A-06-40 is classified CLOSED – ACCEPTABLE ALTERNATE ACTION.

From: FAA
To: NTSB
Date: 9/7/2010
Response: CC# 201000348: - From J. Randolph Babbitt, Administrator: As stated in the Federa1 Aviation Administration's previous response, the left and right fuel systems on the Convair 580 aircraft operate independently under all normal conditions; pressure on one side does not affect the other side. Requiring Convair 580 operators to comply with this recommendation would have little, if any, effect for normal operation and marginal effect if the system were operated incorrectly. We determined the Convair 580 fuel system is acceptable as designed if operated in accordance with the approved airplane flight manual and no unsafe condition exists. We did, however, issue Special Airworthiness Information Bulletin (SAIB) NE-07-24 on April 3, 2007 to provide awareness to owners/operators to mitigate any potential risk. The Board's January 2008 response requested the FAA conduct a survey of Convair 580 operators, showing that all operators have complied with the SAIB, in order to constitute an acceptable alternative means of addressing the recommendation. As the Board correctly noted in the same response, however, an SAIB is issued only to provide information and compliance is not mandatory. The nature of an SAIB inherently excludes the requirement to survey for compliance because it is not mandatory and is not intended as a means to correct an unsafe condition. The SAIB encourages the implementation of new approaches or makes the affected parties aware of a potential issue with the means to mitigate the associated risk. The typical distribution for an SAIB includes all known aircraft owners/operators, FAA Flight Standards Fielded Offices, and manufacturers. The SAIB's design and intent is such that tracking communication and monitoring a recipient's response to an SAIB are not possible on a typical project. Although we would not typically conduct a survey for an SAIB, we did so in this case because of the limited number of aircraft and operators. There are a total of 15 Convair 580 aircraft in the U.S. fleet, 14 active and I inactive. Of the five operators, four have active aircraft and have either provided the SAIB and the safety alert for operators to their aircrews or updated training materials and procedures in accordance with the recommendations. For the one operator that has the inactive Convair 580, nothing was done because the aircraft is not airworthy. We believe we have made the appropriate safety decision and consider our actions complete.

From: NTSB
To: FAA
Date: 1/11/2008
Response: The FAA determined that the left and right fuel systems on the Convair 580 aircraft operate independently under all normal conditions and that different fuel boost pump pressures have no effect under normal operating conditions. Consequently, the FAA believes that requiring Convair 580 operators to take the recommended action would have little if any effect on normal operations and only marginal effect if the system were operated incorrectly. However, on April 3, 2007, the FAA issued Special Airworthiness Information Bulletin (SAIB) NE-07-24, which recommends that Convair 580 operators use identical fuel boost pump pressures in both tanks. In its report on the Air Tahoma accident, the Safety Board found that the inadvertent fuel transfer due to different fuel pump output pressures was not an isolated event. The report discussed the September 21, 2004, Nolinor Aviation event, in which a Convair 580 experienced an in-flight fuel imbalance due to the left and right fuel boost pumps’ being set for different output pressures and the fuel crossfeed valve’s being left open, causing unintentional fuel transfer. The Board believes that the differential pump pressures act like a latent failure. The Air Tahoma accident was a case in which the open fuel crossfeed valves were not monitored or identified by either the pilot or co pilot, despite the co-pilot’s complaints regarding the airplane’s handling. The Air Tahoma and Nolinor events indicate that since crossfeed valves can be left open and forgotten, similar pump output pressures would effectively prevent unintentional fuel transfer and the outcomes of these events. Although the SAIB has already been issued, the Safety Board believes that the document should have discussed that, although the fuel system presently in use is acceptable and different fuel boost pump output pressures do not constitute hazards by themselves, when different pressures are combined with open crossfeed valves, a safety risk occurs. Were compliance with the SAIB mandatory, its issuance would have satisfied the intent of this recommendation. However, an SAIB is issued only to provide information, and compliance is not mandatory. If the FAA can show by surveying U.S. Convair 580 operators that all have set the fuel pump output pressures to the same setting, as recommended in the SAIB, the issuance of the SAIB will constitute an acceptable alternative means of addressing the recommendation. Accordingly, pending results of such a survey, Safety Recommendation A-06-40 is classified OPEN -- ACCEPTABLE RESPONSE.

From: NTSB
To: FAA
Date: 9/4/2007
Response: The FAA indicated in its August 1, 2006, letter that because Canada is the state of design for the Convair 580, the FAA had initiated discussions with Transport Canada Civil Aviation (TCCA) regarding the recommended action. Safety Recommendation A-06-41 was issued to the TCCA at the same time as this recommendation was issued to the FAA and asked the TCCA to take the same action recommended in Safety Recommendation A-06-40. On December 1, 2006, the TCCA indicated that it did not intend to take the recommended action. As a result, Safety Recommendation A-06-41 was classified Closed Unacceptable Action. On June 15, 2006, the Safety Board wrote to the FAA regarding safety recommendations concerning aircraft for which the type certificate holder is not a U.S. organization. In that letter, the Board indicated its belief that the International Civil Aviation Organization’s (ICAO’s) Chapter 6, Annex 13, paragraph 6.8, can be interpreted to mean that the FAA may be considered the appropriate recipient of recommendations concerning foreign-designed or -manufactured products. Therefore, the Board believes that the FAA can and should take the recommended action for U.S. operators of the Convair 580. Pending implementation of a requirement that Convair 580 operators set the left and right fuel boost pump output pressure to the same setting, Safety Recommendation A-06-40 is classified OPEN -- ACCEPTABLE RESPONSE.

From: FAA
To: NTSB
Date: 7/25/2007
Response: Letter Mail Controlled 8/1/2007 11:36:47 AM MC# 2070384: - From Marion C. Blakey, Administrator: This is in further response to Safety Recommendation A-06-40 issued by the Board on May 17,2006, and supplements our letter dated August 1,2006. This safety recommendation was issued as a result of an accident on August 13,2004, about 0049 eastern daylight time, involving Air Tahoma, Inc., flight 185, a Convair 580, N586P. The airplane crashed about 1 mile south of Cincinnati/Northern Kentucky International Airport, Covington, Kentucky, while on approach to runway 36R. The first officer was killed, and the captain received minor injuries. The airplane was destroyed by impact forces. The flight was operating under the provisions of 14 CFR Part 12 1 as a cargo flight for DHL Express from Memphis International Airport, Memphis, Tennessee, to Covington, Kentucky. Visual meteorological conditions prevailed for the flight, which operated on an instrument flight rules flight plan. The Federal Aviation Administration has reviewed the following technical data provided by Keloma Flightcraft Convair Division, the type certificate holder for Model Convair 580 airplanes, and the Board: NTSB Aircraft Accident Report NTSB/AAR-06/03; Allison Prop-Jet Convair Bulletin 10-2 1 dated October 10, 1969; and AFM-lCC1-1 dated Revised- 29 October 1984. We have determined that the left and right fuel systems on the Convair 580 aircraft operate independently under all normal conditions. Pressure on one side does not affect the other side. Therefore, different fuel boost pump pressures would have no effect under normal operating conditions. Any attempt to regulate the pump output pressures to equal values would only be practical during static (no flow) conditions as system distribution, pump variables, and engine demands would change the output continuously during operation. Consequently, requiring Convair 580 operators to set the left and right fuel boost pump output pressure settings on their airplanes to the same setting would have little if any effect for normal operation and marginal effect if the system were operated incorrectly. We plan to issue a Special Airworthiness Information Bulletin that will recommend operators of the Convair 580 operate with identical fuel boost pump pressures in both tanks. We believe that the fuel system is acceptable, if it is operated in accordance with the approved Airplane Flight Manual AFM-1CC1-1.

From: FAA
To: NTSB
Date: 8/1/2006
Response: Letter Mail Controlled 8/15/2006 8:45:38 AM MC# 2060398: - From Marion C. Blakey, Administrator: The Federal Aviation Administration shares the Board’s concerns about the safety issues addressed in the safety recommendation. The FAA has initiated discussions with Transport Canada Civil Aviation since Canada is the State of Design for the Convair 580. We will work closely with them to develop a comprehensive solution from a certification, maintenance, and operational perspective that will properly address this safety recommendation. We will provide a final response by December 31,2006.