PHMCH

HISTORY OF FLIGHT

On May 28, 1996, at 1421 eastern daylight time, a Boeing 767-31AER, with Dutch registry PH-MCH, and operated by Martinair Holland as flight 631, received minor damage during an unscheduled landing at Logan Airport, Boston, Massachusetts. There were no injuries to the 3 pilots, 8 flight attendants, or 191 passengers, and visual meteorological conditions prevailed. The flight had departed Schiphol Airport, Amsterdam, The Netherlands, at 0649, destined for Orlando, Florida (MCO), and was operated on an instrument flight rules (IFR) flight plan under 14 CFR 129.

The flight was initiated with three pilots; a captain, a relief captain (F/O 1), and a first officer (F/O 2).

Prior to departure, the flight crew noted anomalies with the airplane clocks. Once corrected, they proceeded with the flight. En route, the airplane experienced numerous electrical anomalies where various warning lights would illuminate, and then extinguish. These occurrences were also accompanied by uncommanded auto-pilot disconnects, changes in airplane zero fuel weight, as displayed on the control display unit (CDU) of the flight management system (FMS), and the blanking of transponder codes.

The flight crew, in radio contact with their dispatch center, discussed the situation and agreed that they could continue with the flight. The Boeing Aircraft Company through the Martinair dispatch center supplied technical assistance. A check of the passenger cabin revealed that numerous personal electronic devices (PEDs) were in use. They were requested to be turned off. At one time while over the North Atlantic, there was a period of time when no anomalies occurred. Nearing the North American continent, and with additional anomalies occurring, the flight crew initially planned to divert to Newark, New Jersey. As the electrical anomalies continued, additional systems were affected, and a decision was made to divert to Boston, Massachusetts. Following the decision to divert, there were failures of the co-pilots electronic attitude director indictors (EADI), and electronic horizontal situation indicators (EHSI). Navigation was lost to the captain's EHSI.

During the initial descent into Boston, the aircraft was flown manually due to autothrottle disengagement and multiple A/P disengagements. When the airplane was configured with flaps 1 (slat extension, no trailing edge flaps), the two needles on a cockpit gauge which represented the respective wing slat positions disagreed. The flight crew checked the runway required for landing with zero flaps, and the runway available at Boston. With sufficient runway available, the captain in concert with the other crew member decided to make no more configuration changes, resulting in a leading edge slat only approach speed of 162 kts, Flap problems had been expected by the crew based on the previous events. The slats were visually inspected to be extended. In the cabin the seatbelts signs switched on and off uncommanded.

During the last portion of flight, the Engine Indicating and Crew Alerting System (EICAS) was filled with caution and advisory messages which were read by F/O 2 from the observers seat on request of the captain.

Although no identification could be received from the Instrument Landing System (ILS), the indication on the left Attitude Director Indicator (ADI) and on the standby ADI seemed valid.

On final approach to Boston, numerous warning lights illuminated, extinguished, and other warning lights illuminated.

After touch down reverse thrust and autospeedbrakes were not available. Manual braking was anticipated since the autobrake selector did not latch. Braking was done manually by the captain while the wing spoilers were extended by the F/O 1. Just after touch-down the captain initially used full manual braking. The cabin crew's observations were as if they were riding on gravel (pebbles), and the cockpit crew suspected tire failures just after turning off the runway. The last high speed turn off to the left was taken to vacate runway 4R, on which the airplane was brought to a stop. The pilots reported to feel no effect from the manually selected ground spoilers. In the meantime all main landing gear tires were blown or deflated and the airplane was brought to a stop without fully vacating the runway.

A small wheel brake fire developed after landing and was immediately extinguished by the airport fire fighting personnel.

Approximately 25 minutes after landing, the passengers disembarked using mobile stairs.

The incident terminated during the hours of daylight at 42 degrees, 21 minutes North latitude and 71 degrees, 00 minutes West longitude.

PERSONNEL INFORMATION

The flight was conducted using an augmented flight crew, which consisted of two captain rated pilots, and a first officer. All personnel held the appropriate pilot and medical certificates as issued by the government of The Netherlands. Following is a summary of crew flight experience:

Captain The captain had a total time of 6,600 hours, with 3,738 hours in the Boeing 767, including 607 hours as pilot-in-command in the Boeing 767. He had flown 199 hours in the preceding 90 days, including 188 hours in the Boeing 767.

Relief Captain (F/O 1) The relief captain had a total time of 4,000 hours, with 1,590 hours in the Boeing 767. He had flown 195 hours in the preceding 90 days, including 190 hours in the Boeing 767.

First Officer (F/O 2) The first officer had a total time of 5,180 hours, with 388 hours in the Boeing 767. He had flown 150 hours in the preceding 90 days, all in the Boeing 767.

AIRCRAFT INFORMATION

The airplane was a Boeing 767- 31AER. The airplane was delivered new to Martinair in February 1990, in Martinair's specified configuration. The Boeing production line number was 194. It was maintained utilizing a maintenance program furnished by Boeing, and approved by the Directorate of Civil Aviation, The Netherlands. The last inspection was conducted on May 21, 1996, and the airplane had operated 98 hours since the inspection. The total time for the airframe at the time of landing at Boston was 30,802 hours.

AERODROME INFORMATION

The landing was accomplished on runway 4R which was 10,005 feet long, 150 feet wide, and had a grooved asphalt surface. The airplane turned off the runway at taxiway ROMEO, with about 1,800 feet of runway remaining.

FLIGHT RECORDERS

After the airplane stopped, the cockpit voice recorder operated for over 30 minutes. The cockpit voice recorder was not retained. The digital flight data recorder (DFDR) was retained and forward to the NTSB Laboratory in Washington DC, for readout. According to the Flight Data Recorder (FDR) Specialist's report:

"1. The...[incident] flight, as transcribed was approximately 7:21:19 in duration from liftoff until touchdown. The transition of the...[air/ground] discrete parameter from 'Ground' to 'Air', occurred at 1050:10 Coordinated Universal Time (UTC), or 3:53:42 Elapsed Time, and the aircraft touchdown, as indicated by a spike in vertical acceleration data, occurred at 11:25:45 Elapsed Time., The UTC time of touchdown could not be determined, as the final loss of UTC data occurred at approximately 1813:32 UTC or 11:18:25 Elapsed Time ( about 7 minutes prior to touchdown)..."

"3. The first loss of the airplane's Coordinated Universal Time (UTC) occurred at approximately 1110:13 UTC, or 4:13:35 Elapsed Time. UTC time was lost at least ten separate times during the flight..."

"4. The first change of the Master Warning discrete from 'No Warning' to 'Warning' occurred at about 6:06:00 Elapsed Time, while the aircraft was at an altitude of about 33,000 feet and a latitude/longitude position of about 50.52 degrees North and 22.50 degrees West. Repeated changed in the Master Warning discrete were noted between 7:40:00 and 9:20:00 Elapsed time."

"5. At about 10:45:00 Elapsed time, FDR heading data was lost for the remainder of the incident flight. FDR pitch information were also lost for most of the remainder of the flight."

"6. At about 11:17:30 Elapsed Time, several parameters were lost to the FDR until after the incident flight landing. The following parameters were noted to be lost:

Roll Attitude Pitch Attitude UTC Hours UTC Minutes UTC Seconds Inertial Vertical Speed Speedbrake Handle Position"

"7. Also at about 11:17:30 Elapsed Time, the...[air/ground] discrete changed stated from 'Air" to 'Ground', and the Air Driven Pump discrete changed stated from 'Off' to 'On', and the HF/L/R Keying discrete changed state from 'Not Keyed' to 'Keyed'. These discretes remained recorded in these states until after aircraft touchdown. Several additional discretes changed state at about 11:17:30 Elapsed Time, and subsequently changed state after touchdown and during the landing roll-out...."

The Addendum to the Flight Data Recorder Factual Report stated:

"...The anti-skid fault discrete changed from the 'No Fault' to 'Fault' state at about 1101:00 Elapsed Time. The parameter data remained then the 'Fault' state until after airplane touchdown and rollout, when the recorded data returned to the 'No Fault' state...."

"According to the airplane manufacturer, if the 28V reference voltage is removed from the FDR during normal flight recording operation, subsequent readout of the FDR will result in...The Air/Ground discrete will always indicate 'Ground'...."

TESTS AND RESEARCH

The airplane was examined at Boston, from May 29, through June 2, 1996. The four inboard tires had deflated due to melted fuse plugs, and the four outboard tires were deflated due to the casings being worn through. A detailed examination of the airplane was conducted in an attempt to induce the failures that were reported by the flight crew. The testing included the electrical system, shock testing, and engine runs both in the air and ground mode. The testing was ...