Anchorage, AK, USA
N277WA
McDonnell Douglas MD-11
The flight crew was conducting an international passenger flight under Title 14, CFR Part 121, when they smelled and saw smoke in the cockpit. The pilot declared an emergency, and diverted to the nearest airport, where the airplane landed without incident. According to the flight crew, just prior to the smell and smoke, there was a crew change that required the cockpit security door to be opened and closed. An examination of the security door by maintenance personnel and the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) revealed an excess length of wiring, which provides power to the electrically locking security door, was laying atop the door's metal-encased, unshielded, locking solenoid inside the doorframe. Several of the wires were encased in a plastic anti-chafe mesh. A portion of the mesh was melted, and had the smell of burnt plastic. During a discussion with the IIC, a mechanic said he had seen similar doors overheat when the door and frame were misaligned, prohibiting full extension of the locking bolt. The cockpit door was modified in accordance with Supplemental Type Certificate (STC) ST01391LA, which meets the FAA's requirements for a reinforced cockpit door. The door uses a "demand access" electrically operated door latching solenoid. The door manufacturer issued an addendum to the airplane manufacturer's maintenance manual. The addendum includes removal, installation, and system tests of the striker/solenoid unit. The installation section does not specifically address the issue of securing excess wiring located above the striker/solenoid within the doorframe. The installation instructions do contain a "caution," referencing the need for the security bolt to engage fully. Failure of the bolt to fully engage will cause the solenoid to remain energized and overheat. Construction of the striker/solenoid assembly is such that the metal-encased electrical coil of the unshielded solenoid is the upper-most portion of the assembly within the doorframe. The installation includes a warning light that illuminates if the solenoid does not shut off. The crew did not report seeing the warning light in-flight, and the light and locking mechanism functioned properly during subsequent tests on the ground; it was not tested in-flight. The conversion of the door was completed on March 21, 2003. Prior to the incident, the new security door had been in service about 16,416 flight hours, and 1170 cycles. FAA Advisory Circular (AC) 65-15A, Chapter 11, covers practices and procedures for the installation and maintenance of aircraft electrical wiring. The AC notes that practices and procedures outlined in this section are general recommendations, and are not intended to replace the manufacturer's instructions. Chapter 11, page 441, Slack in Wiring Bundles, states: "Single wires or wire bundles should not be installed with excessive slack." Page 442, Routing and Installations, states: "All wires and wire groups should be routed and installed to protect them from: (2) high temperatures."
On April 28, 2005, about 0530 Alaska daylight time, a Mc Donnell Douglas MD-11 airplane, N277WA, sustained minor damage resulting from an electrical anomaly on the flight deck during normal cruise, about 950 miles southwest of Anchorage, Alaska. The airplane was being operated as Flight 8278, by World Airways, Inc., of Peachtree City, Georgia, as an instrument flight rules (IFR) non-scheduled international passenger flight under Title 14, CFR Part 121, when the incident occurred. The three flight crew members, three reserve flight crew members, 6 cabin crew members, and 189 passengers were not injured. Visual meteorological conditions prevailed, and an instrument flight plan was filed. The flight originated at Osan Air Base, South Korea, and was bound for the Seattle International Airport, Seattle, Washington. The flight departed Osan Air Base April 27, about 2355. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on April 28, the Anchorage FAA Regional Operations Center specialist said the flight crew reported smoke in the cockpit, declared an emergency, and diverted to the Ted Stevens Anchorage International Airport, Anchorage. There were no other system anomalies reported by the flight crew, and the airplane landed without incident. During an examination of the airplane's flight deck by maintenance personnel and the IIC on April 28, heat damaged wiring was discovered in the doorframe above the locking solenoid of the cockpit security door. According to members of the flight crew, just prior to the smell and visible smoke in the cockpit, there was a crew change that required the cockpit door to be opened and closed. The inspection of the cockpit security door by the NTSB IIC revealed that an excess length of wiring, which provides power to the electrically locking security door, was laying atop the metal-encased, unshielded, solenoid inside the doorframe. Several of the wires were encased in a plastic anti-chafe mesh. A portion of the mesh was melted, and had the smell of burnt plastic. During a discussion with the IIC, a mechanic said he had seen similar doors overheat when the door and frame were misaligned, and the bolt could not fully extend. The cockpit door had been modified from its original configuration in accordance with Supplemental Type Certificate (STC) ST01391LA, which was issued to C & D Interiors, a division of C & D Aerospace, Huntington Beach, California. The installation meets the FAA's requirements for a reinforced cockpit door. The door uses a "demand access" electrically operated door latching solenoid. Criteria for the construction and operation of cockpit security doors is found in FAA Advisory Circular (AC) 25.783-1A. The conversion of the door was completed on March 21, 2003. Prior to the incident, the new security door had been in service about 16,416 flight hours, and 1170 cycles/flights. C & D Aerospace issued an addendum to the Boeing MD-11 maintenance manual titled: Cockpit Security Door Striker/Solenoid Assembly - Maintenance Practices. The addendum includes removal, installation, and system tests of the striker/solenoid unit. The installation section does not specifically address the issue of securing excess wiring located above the striker/solenoid within the doorframe. The installation instructions do contain a "caution," referencing the need for the security bolt to engage fully. Failure of the bolt to fully engage will cause the solenoid to remain energized, and overheat. Construction of the striker/solenoid assembly is such that the metal-encased, unshielded electrical coil of the solenoid is the upper most portion of the assembly within the doorframe. The installation does include a warning light that illuminates in the event the solenoid does not shut off. The crew did not report seeing the warning light in-flight. The light and locking mechanism functioned properly during subsequent tests on the ground; it was not tested in-flight. FAA Advisory Circular (AC) 65-15A, chapter 11, covers generally accepted practices and procedures for the installation and maintenance of aircraft electrical wiring. The AC does note however, that practices and procedures outlined in this section are general recommendations and are not intended to replace the manufacturer's instructions and approved practices. Chapter 11, page 441, Slack in Wiring Bundles, states: "Single wires or wire bundles should not be installed with excessive slack." Page 442, Routing and Installations, states: "All wires and wire groups should be routed and installed to protect them from: (2) high temperature."
The inadequate installation of the cockpit security door locking device, which resulted in smoke in the cockpit during normal cruise, and a precautionary landing. A factor associated with the incident was the manufacturer's insufficiently defined installation instructions.
Source: NTSB Aviation Accident Database
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