Leita
Fleet implement of design change
Tillaga í öryggisátt
The Icelandic Transportation Safety Board (ITSB) recommends to Boeing, to issue the planned service bulletin 757-SB57A0154 to support fleet wide replacement of the Blocking and Thermal Relief Valve Housing in co-operation with the actuator‘s manufacturer.
Afgreiðsla
Boeing plans to release Boeing Alert Service Bulletin 757-SB-27A0154 on June 25 2016. In addition the FAA has issued Safety Recommendation 15.115, a Boeing 757 airplane level safety issue, mandating evaluation of the spoiler actuator's blocking and thermal relief valve housing failure to determine appropriate corrective action.
Research of similar design
Tillaga í öryggisátt
The Icelandic Transportation Safety Board (ITSB) recommends to Boeing, to research other Boeing large transport category aircraft for similar spoiler actuator design and take corrective action as needed .
Afgreiðsla
The FAA has issued Safety Recommendation 15.116, gathering and reviewing compliance data, including hazard assessments, for each type of Title 14, Code of Federal Regulations (14 CFR) Part 25 airplane operating under part 121. The FAA will be addressing Safety Recommendation 15.116 for U.S.-manufactured aircraft.
FAA mandate of design change
Tillaga í öryggisátt
The Icelandic Transportation Safety Board (ITSB) recommends to the FAA, to research the need for making inspections, and possible replacement, of spoiler actuator’s Blocking and Thermal Relief Valve Housing mandatory via issue of airworthiness directive, for Boeing 757 airplanes.
Afgreiðsla
The FAA has issued Safety Recommendation 15.115, a Boeing 757 airplane level safety issue, mandating evaluation of the spoiler actuator's blocking and thermal relief valve housing failure to determine appropriate corrective action.
Update 31.01.2017:
The FAA has reviewed and determined that the latent failure of the spoiler power control unit Blocking and Thermal Relief Valve (BTRV) housing does manifest itself when the hydraulic system it is attached to fails. The failure causes an uncommanded extension of the spoiler panel, known as spoiler panel float. The result of multiple spoiler panel floating can lead to the loss of the airplane. The FAA's Aircraft Certification Service has determined this is a safety issue and the FAA is in the process of publishing an airworthiness directive to address it.
Updated 6.10.2017:
The FAA has issued Airworthiness Directive 2017-04-07, mandating that within 51 months after January 23 2017, for all Boeing 757-200, -200PF, -200CB, and -300 series airplanes, certificated in any category, each spoiler power control unit (PCU) must be replaced with a new or changed PCU at spoiler positions 2, 3, and 4 on the left wing, and spoiler positions 9, 10, and 11 on the right wing, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 757-27A0154, dated July 22, 2016. This concludes the above safety recommendation issued by the Icelandic Transportation Safety Board on August 13th, 2015.
FAA mandate of research of similar design
Tillaga í öryggisátt
The Icelandic Transportation Safety Board (ITSB) recommends to the FAA, to research the need for making inspections, and possible replacement, of spoiler actuator’s Blocking and Thermal Relief Valve Housing mandatory via issue of airworthiness directive, for other large transport category aircraft with similar spoiler actuator design.
Afgreiðsla
The FAA has issued Safety Recommendation 15.116, gathering and reviewing compliance data, including hazard assessments, for each type of Title 14, Code of Federal Regulations (14 CFR) Part 25 airplane operating under part 121. The FAA will be addressing Safety Recommendation 15.116 for U.S.-manufactured aircraft. Furthermore, the FAA recommended to the ITSB to provide a similar recommendation to foreign aviation authorities for each State of design. The board of ITSB approved on a board meeting held on January 15th, 2016, to contact other states of designs of aircraft of similar spoiler design and extend the recommendation as needed.
Update: 31.01.2017:
The FAA has reviewed the design, manufacturing, and service information and determined the Boeing Model 757 failed BTRV housing was under-designed in that it had insufficient fatigue life. The reason for this was found to be a design error that led to a premature failure. The valve itself was designed by a third party, Moog, which reported that the valve is used only on the Boeing Model 757 series airplanes. Therefore this under-designed part is not on any other transport airplanes. Additionally, a quary of the FAA Service Difficulty Report (SDR) database did not reveal any other spoiler issue associated with the blocking/thermal relief valves in the past fifteen years on any transport airplanes. The FAA considers its action to Safety Recommendation 15.116 completed.