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Safety Recommendation Details

Safety Recommendation A-06-041
Details
Synopsis: On August 13. 2004, about 0049 eastern daylight time. Air Tahoma, Inc., flight 185, a Convair 580, N586P, crashed about 1 nlile south of CincinnatiINorthern 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 Regulations Part 12 1 as a cargo flight for DHL Express 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 TRANSPORT CANADA: 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: 8/11/2010
Addressee(s) and Addressee Status: Foreign, Canada, Transport Canada, Civil Aviation (Closed - Acceptable Alternate Action)
Keyword(s): Flightcrew, Procedures, Procedures: Flightcrew

Safety Recommendation History
From: NTSB
To: Foreign, Canada, Transport Canada, Civil Aviation
Date: 8/11/2010
Response: The NTSB notes that the TCCA issued Service Difficulty Advisory AV 2009-06 (which encourages Convair 580 operators to ensure that both their fuel boost pumps are set to the same pressure and points out 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) on December 8, 2009. We are aware that this document does not constitute the recommended requirement; however, we also note that the TCCA surveyed Canadian Convair 580 operators to confirm that they had taken the recommended action and that 26 (86.6 percent) of the 30 registered aircraft that remain in service had complied as of December 2009. Although the TCCA was unable to confirm that the entire Canadian Convair 580 fleet had configured both boost pumps as recommended, because of the high percentage of the fleet in compliance and the TCCA's efforts to inform all operators of the potential risk associated with this hazardous configuration, we believe that the TCCA's actions represent an acceptable alternate means of addressing the recommendation. Accordingly, Safety Recommendation A-06-41 is classified CLOSED – ACCEPTABLE ALTERNATE ACTION.

From: Foreign, Canada, Transport Canada, Civil Aviation
To: NTSB
Date: 12/24/2009
Response: Letter Mail Controlled 1/20/2010 10:06:53 AM MC# 2100023 - From Martin J. Eley, Director General, Civil Aviation: The Aircraft Flight Manual (AFM) prohibits fuel transfer from one tank to the other while the airplane is on the ground or in flight. The AFM also prohibits the transfer of fuel from one tank to the other and cautions, "to do so might build up excessive pressure in a tank, which could result in structural failure or cause fuel to overflow through the vent." The AFM also states, "When operating the crossfeed system, turn off fuel valve for tank not being used," which would preclude fuel transfer. Transport Canada has produced Service Difficulty Advisory AV 2009-06 to emphasizes the importance of adhering to the manufacturer's approved operating procedures regarding cross feeding of he1 and the need to reinforce those procedures in the lraining program. The advisory is being disseminated to the aviation community and foreign airworthiness authorities. Advisory AV 2009-06 is available on the Transport Canada web site at: http://www.tc.gc.calcivilaviation/certifcation/continuing/advisory/2009-06.htm. Transport Canada has also conducted a survey of the Convair 3401440 (580) Canadian operators, to establish the fleet status for Service Bulletin PJCB 10-21. There are 32 aircraft in the Canadian fleet and research demonstrates that 86.6% of Canadian aircraft are configured post Service Bulletin PJCB 10-21. It is important to realize that even though an aircraft may be configured with pre or post Service Bulletin fuel pumps, the inadvertent transfer of fuel is likely to occur should the cross-feed valve remain selected open. Transport Canada trusts that this action will be acceptable to the NTSB allowing a positive reassessment of the above recommendation. Please be assured that all due consideration has been given to this recommendation and I thank you and your organisation for the information regarding the Convair 3401440 (580). Should NTSB officials have any questions concerning this matter, please contact Mr. Steve Dudka of Aviation Safety Analysis at 613-949-3825.

From: NTSB
To: Foreign, Canada, Transport Canada, Civil Aviation
Date: 7/17/2009
Response: The NTSB notes that in December 2006, TCCA concluded that, although it is desirable to use the same output pressure settings, doing so would not ensure an identical output pressure at each fuel boost pump and therefore would not prevent fuel transfer. TCCA indicated its position that the adoption of this recommendation would not mitigate the risk of a similar accident and that, therefore, it did not plan to take the recommended action. On September 4, 2007, the NTSB replied that, although it agreed that different fuel pump output pressures had not been a factor in the cause of the Air Tahoma accident and that taking the recommended action would not prevent a similar accident, the Air Tahoma and the September 21, 2004, Nolinor Aviation events indicated that, because crossfeed valves can be left open and forgotten, similar pump output pressures would effectively prevent unintentional fuel transfer and the outcomes of these events. The NTSB believed that the differential pump pressures act like a latent failure, and the NTSB continued to believe in the need for this recommendation. Because TCCA stated it did not plan to take the recommended action, Safety Recommendation A-06-41 was classified Closed Unacceptable Action. In its recent letter, TCCA stated that, although it remains committed to its original position, it will produce an advisory notice to disseminate information as recommended in Propjet Convair Bulletin 10-21. The advisory notice will recommend that Convair 580 operators review their boost pump installations to verify that the same configuration is installed on both sides and that the pressure switch and fuel pressure settings are adjusted for the appropriate installation as required. The NTSB believes that it is important that the advisory notice also highlight 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. The NTSB points out that an advisory notice is issued only to provide information, and compliance is not mandatory. Therefore, its issuance, alone, would not satisfy the intent of this recommendation. However, if TCCA can show, by surveying Canadian Convair 580 operators, that all have set fuel pump output pressures to the same setting, as recommended in the advisory notice, the issuance of the advisory notice will constitute an acceptable alternative means of addressing the recommendation. Pending our receipt and review of the results of such a survey, Safety Recommendation A-06-41 will remain classified CLOSED -- UNACCEPTABLE ACTION.

From: Foreign, Canada, Transport Canada, Civil Aviation
To: NTSB
Date: 8/6/2008
Response: Letter Mail Controlled 8/21/2008 3:51:30 PM MC# 2080506: - From Melin Preuss, Director General, Civil Aviation: As you are aware, the concerns you expressed in your letter of May 29,2008, in regards to the Transport Canada Civil Aviation (TCCA) response to the National Transportation Safety Board (NTSB) Recommendation A-06-41, were entered into the Civil Aviation Issues Reporting System (CAIRS) and were assigned file number AI-4241. Transport Canada has again reviewed all pertinent information and data surrounding this incident and remains committed to our original position as stated in our letter of December 20,2007 to the NTSB. Additionally, further research has highlighted the fact that if the boost pumps are set to similar pressures and within the tolerances specified in the maintenance manual and Propjet Convair Bulletin (PJCB) 10-2 1, as recommended by the NTSB, the ability to have a pressure differential of 2 pounds per square inch (PSI) between the 2 boost pumps still exists. As such, if the fuel system is not operated in accordance with the approved flight manual procedures, fuel transfer between wing tanks will still occur if the crossfeed valve is opened without an appropriate wing tank valve being selected to the closed position. In spite of the aforementioned information, Transport Canada will produce an advisory notice to disseminate the information as recommended in service bulletin PJCB 10-21. Convair 580 operators should review their boost pump installations to determine that the same configuration, is installed on both sides and that the pressure switch and fuel pressure settings are adjusted for the appropriate installation as required. This notification will be distributed to all Canadian owners of the affected product and to those affected foreign states of registry for disposition as per International Civil Aviation Organisation (ICAO) Annex 8. Transport Canada trusts that this action will be acceptable to the NTSB. Please be assured that all due consideration has been given to this recommendation and I thank you and your organisation for this information.

From: NTSB
To: Foreign, Canada, Transport Canada, Civil Aviation
Date: 5/29/2008
Response: On December 1, 2006, TCCA indicated that together with Kelowna Flightcraft (the Convair 580 type certificate holder), it had reviewed the Convair 580 fuel crossfeed system and related airplane flight manual procedures. TCCA concluded that, although it is desirable to use the same output pressure settings, doing so would not ensure an identical output pressure at each fuel boost pump and therefore would not prevent fuel transfer. TCCA concluded that an unsafe condition did not exist, and it therefore did not believe that adoption of this recommendation would mitigate the risk of a similar accident. As a result, TCCA did not plan to take the recommended action. On September 4, 2007, the Safety Board replied that although we agreed that different fuel pump output pressures had not been a factor in the cause of the Air Tahoma accident, and that taking the recommended action would not prevent a similar accident, the Air Tahoma and the September 21, 2004, Nolinor Aviation events indicated that because crossfeed valves can be left open and forgotten, similar pump output pressures would effectively prevent unintentional fuel transfer and the outcomes of these events. The Board believed that the differential pump pressures act like a latent failure, and the Board continued to believe in the need for this recommendation. Because TCCA stated it did not plan to take the recommended action, Safety Recommendation A-06-41 was classified Closed Unacceptable Action. In its recent letter, TCCA stated that it again had reviewed the Safety Board’s report on the Air Tahoma accident and all associated documents within TCCA, and it had conferred with Kelowna Flightcraft and the Canadian Transportation Safety Board regarding the Air Tahoma accident and Safety Recommendation A-06-41. After discussing the points the Safety Board had made in its September 4, 2007, letter, TCCA again concluded that Safety Recommendation A-06-41 would not reduce the risk of recurrence of an event similar to the Air Tahoma accident and that an unsafe condition did not exist. Safety Recommendation A-06-40, issued to the Federal Aviation Administration (FAA) when Safety Recommendation A-06-41 was issued to TCCA, asked for the same action for U.S. operators. On July 25, 2007, the FAA informed the Safety Board that because the left and right fuel systems on the Convair 580 operate independently under all normal conditions and that different fuel boost pump pressures have no effect under these conditions, the FAA believed 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 recommended that Convair 580 operators use identical fuel boost pump pressures in both tanks. On January 11, 2008, the Board replied to the FAA that if compliance with the SAIB were mandatory, its issuance would have satisfied the intent of Safety Recommendation A-06-40. However, an SAIB is issued only to provide information, and compliance is not mandatory. If the FAA could 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, issuance of the SAIB would constitute an acceptable alternative means of addressing the recommendation. Pending results of such a survey, Safety Recommendation A-06-40 was classified Open Acceptable Alternate Response. The Safety Board has considered the points raised by TCCA in its December 20, 2007, letter, but we continue to believe that differential pump pressures act like a latent failure and that the action recommended in Safety Recommendation A-06-41 is still needed. However, if TCAA takes action in a timely manner, issuing guidance material to Convair 580 operators to make them aware of the possibility of differential pump output pressures, similar to the FAA’s SAIB, and following up with operators to confirm that they have taken the recommended action, the Safety Board would consider this an acceptable alternative response by TCCA and could reclassify the recommendation as such.

From: Foreign, Canada, Transport Canada, Civil Aviation
To: NTSB
Date: 12/20/2007
Response: Letter Mail Controlled 1/15/2008 10:36:00 AM MC# 2080011: - From Merlin Preuss, Director General, Civil Aviation: As you are aware,, the recent concerns you expressed in your submission of October 4,2007, in connection with the National Transportation Safety Board’s (NTSB’s) assessment of Transport Canada’s (TC’s) response to Safety Recommendation A-06-4 1;which recommends requiring Convair 580 operators to set the left and right fuel boost pump output pressure settings on their airplanes to the same setting, were entered into the Civil Aviation Issues Reporting System (CAIRS) and were assigned file number TN-3 152. Please accept my apologies for the delay in responding to your submission. The appropriate officials have again reviewed the NTSB report, all associated documents within their branches, conferred with the type certificate holder and the Canadian Transportation Safety Board (TSB) regarding this occurrence and the subsequent recommendation. TC regrets the NTSB’s assessment of TC’s action to A-06-41 as Closed-Unacceptable, and offers the following points for the Board’s consideration. The Department understands that the NTSB has based its assessment upon two points. Both points are addressed below. The NTSB letter states, Although the Safety Board agrees that the difference in fuel pump output pressures was not a factor in the cause of the Air Tahoma accident, and taking the recommended action would not prevent a similar accident, we emphasize conclusion 14 from the report of the Air Tahoma accident investigation: Fuel transfer can occur on the Convair 580 airplane if it is operated with different fuel boost pump output pressure settings and with the fuel crossfeed valves unintentionally left open. TC and the type certificate holder are in agreement that a 5 pounds per square inch (psi) pressure differential between boost pump pressures during an unintentional crossfeed switch selected OPEN would not significantly contribute to the fuel imbalance experienced by Air Tahoma’s 80 minute flight and would not significantly affect the safety of any flight. TC understands the only fuel system configuration testing the NTSB carried out during their investigation was on April 12 and 13, 2005, at Argo-Tech Corporation’s facility in Cleveland, Ohio. The NTSB aircraft accident report states, The fuel boost pump tests simulated crossfeed operation from the left fuel tank, through a non-operating right fuel boost pump and an open right fuel tank shutoff valve, consistent with the airplane’s approximate fuel system configuration during the last portion of the accident flight (1.16.2). However, conclusion 14 is based upon both boost pumps operating at different output pressure settings during an unintentional crossfeed operation. The report does not identify any other tests simulating a crossfeed operation with both boost pumps selected ON, one set at 20 psi and the other set at 15 psi, to support conclusion 14. Furthermore, the NTSB test at Argo-Tech did not identify the affect of power plant fuel burn during fuel transfer to the right fuel tank. TC notes that the NTSB states in conclusion 14, Fuel transfer can occur on the Convair 580 airplane rather than stating fuel transfer will occur on the Convair 580 airplane, The report does not identify quantitative results to substantiate a firm conclusion. The report fails to mention data that supports the fuel flow rate of fuel crossfeed under normal operation with crossfeed open, and that the rate would lead to an excessive rate of fuel transfer. The NTSB letter also states, The Safety Board further emphasizes that the Air Tahoma accident was not an isolated event. The Board’s 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 booster pumps being set for differential output pressures and the fuel crossfeed valve’s being left open, causing unintentional fuel transfer. The NTSB report’s reference to the Nolinor 2000 Ib. fuel imbalance incident on September 21,2004 does not provide sufficient data to confirm a 6 psi differential boost pump pressure (right set at 15 psi and left set at 21 psi) was the cause. The report states, In addition, the maintenance personnel left the fuel crossfeed valve open after performing postinstallation checks on the left fuel boost pump” (1.18.1). The TSB preliminary report (A04QO 152) on the Nolinor incident and the NTSB report DCA04MA168 do not indicate the left and right fuel tank loads before flight, the ramp time and the flight time etc. making it difficult for TC to determine differential boost pump pressures were the main cause. However, it is clear that the flight crew operated the aircraft outside the aircraft’s Aircraft Flight Manual (AFM). TC reaffirms its position that the NTSB report, as it stands, does not substantiate recommendation A-06-41 as mitigation for the risk of reoccurrence of a like accident or that an unsafe condition exists. TC National Aircraft Certification specialists are prepared to further discuss this matter with the recommendation authors, if desired.

From: NTSB
To: Foreign, Canada, Transport Canada, Civil Aviation
Date: 9/4/2007
Response: The Safety Board notes that the TCCA, together with Kelowna Flightcraft, (the Convair 580 type certificate holder), reviewed the Convair 580 fuel cross-feed system and related airplane flight manual procedures. This review concluded that, although it is desirable to use the same output pressure settings, doing so will not ensure an identical output pressure at each fuel boost pump and therefore will not prevent fuel transfer. Given the Safety Board’s findings from the Air Tahoma accident, the review further concluded that an unsafe situation did not exist. Therefore, the TCCA does not believe that adoption of this recommendation would mitigate the risk of a similar accident, and the TCCA does not plan to take the recommended action. Although the Safety Board agrees that the difference in fuel pump output pressures was not a factor in the cause of the Air Tahoma accident, and taking that the recommended action would not prevent a similar accident, we emphasize conclusion 14 from the report of the Air Tahoma accident investigation: Fuel transfer can occur on the Convair 580 airplane if it is operated with different fuel boost pump output pressure settings and with the fuel crossfeed valves unintentionally left open. The Safety Board further emphasizes that the Air Tahoma accident was not an isolated event. The Board’s 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. Although the pumps cannot be set to exactly the same output pressures, resulting in some small pressure differential, 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. The Safety Board continues to believe in the need for this recommendation and is disappointed that the TCCA will not take the recommended action; therefore, Safety Recommendation A-06-41 is classified CLOSED -- UNACCEPTABLE ACTION.

From: Foreign, Canada, Transport Canada, Civil Aviation
To: NTSB
Date: 12/1/2006
Response: Letter Mail Controlled 12/19/2006 9:32:39 AM MC# 2060600: - From Merlin Preuss, Director General, Transport Canada - Civil Aviation: It should be noted that the Aircraft Accident Report, NTSB/AAR-06-03, page 34, 3rd paragraph states in part, operating the Convair 580 with different fuel boost pump output pressure settings does not in itself create an unsafe operating condition and, "Such operation did not factor in the accident. In addition, Section 3.2, Probable Cause, page 38 states, "The National Transportation Safety Board determines that the probable cause of this accident was fuel starvation resulting from the captain's decision not to follow approved fuel crossfeed procedures." Transport Canada in conjunction with the type certificate holder has completed a review of the Convair 580 fuel cross-feed system and related AFM procedures. The recommendation attempts to address the possibility of one operating fuel boost pump pumping fluid to both its respective engine and through the cross-feed valves to the other engine and tank. Although it is desirable to have the same output pressure settings on the fuel boost pumps, this will not assure an identical output pressure at each fuel boost pump and thus will not prevent fuel transfer. The review did not indicate to Transport Canada that an unsafe situation exists. Transport Canada therefore does not believe that adoption of this recommendation would mitigate the risk of a similar accident, and as such, pending further evidence to support the subject recommendation, Transport Canada is not considering adoption of Recommendation A-06-41.

From: Foreign, Canada, Transport Canada, Civil Aviation
To: NTSB
Date: 6/2/2006
Response: Letter Mail Controlled 6/20/2006 1:59:12 PM MC# 2060294: - From Melin Preuss, Director General, Civil Aviation: This is to acknowledge receipt of your letter of May 17,2006 in regards to the August 13, 2004 accident involving the Air Tahoma, Inc., Convair 580, U.S. registration N586P, near Cincinnati/Northern Kentucky International Airport, Covington, Kentucky, which contained one recommendation (A-06-41) to Transport Canada. The appropriate officials are reviewing the subject report and recornmendation and the Department will respond in accordance with ICAO .Annex 13 to the Convention on International Civil Aviation, Aircraft Accident and Incident Investigation, Chapter 6, Paragraph 6.10 which states, “A state that receives safety recommendations shall inform the proposing State of the preventive action taken or under consideration, or the reasons why no action will be taken.” Please be assured that all due consideration will be given to this recommendation. I thank you and your organisation for this important safety information. Should NTSB officials have any questions concerning this matter, please contact Mr. David Laronde of System Safety at 6 1 3-991 -01 25,