Tokyo-Narita

In this accident, when the airplane landed on Runway 34L at Narita International Airport, it fell into porpoising. It is highly probable that the left wing fractured as the load transferred from the left MLG to the left wing structure on the third touchdown surpassed the design limit (ultimate load). It is highly probable that a fire broke out as the fuel spillage from the left wing caught fire, and the airplane swerved left off the runway rolling to the left and came to rest inverted on the grass area. The direct causes which the airplane fell into the porpoise phenomenon are as follows:
a. Large nose-down elevator input at the first touchdown resulted in a rapid nose down motion during the first bounce, followed by the second touchdown on the NLG with negative pitch attitude. Then the pitch angle rapidly increased by the ground reaction force, causing the larger second bounce, and
b. The PF‘s large elevator input in an attempt to control the airplane without thrust during the second bounce. In addition, the indirect causes are as follows:
a. Fluctuating airspeed, pitch attitude due to gusty wind resulted in an approach with a large sink rate,
b. Late flare with large nose-up elevator input resulted in the first bounce and
c. Large pitch attitude change during the bounce possibly made it difficult for the crewmembers to judge airplane pitch attitude and airplane height relative to the ground (MLG height above the runway).
d. The PM‘s advice, override and takeover were not conducted adequately. It is somewhat likely that, if the fuse pin in the MLG support structure had failed and the MLG had been separated in the overload condition in which the vertical load is the primary component, the damage to the fuel tanks would have been reduced to prevent the fire from developing rapidly. It is probable that the fuse pin did not fail because the failure mode was not assumed under an overload condition in which the vertical load is the primary component due to the interpretation of the requirement at the time of type certification for the MD-11 series airplanes.

The flight crews' failure to verify that the number of landing gear annunciations on the second officer’s panel was consistent with the number specified in the abnormal/emergency procedures checklist, which led to a landing with the nose gear retracted.

The accident was the consequence of a series of error and omissions on part of the flying crew, resulting in a controlled flight into terrain.
The following contributing factors were reported:
- The pilots did not slow the aircraft to approach speed when directed by ATC (Event69). This error put the aircraft over VJN VOR/DME approximately 15 minutes earlier than ATC expected. The average ground speed inbound to the VOR/DME, between Event65 (DME 37 nmi) and Event104 (DME 0.0 nmi), was 400 knots.
- The pilots did not descend according to the published descent profile for their arrival sector. If the pilots had done this the aircraft would have been at 4,000 feet altitude over the VJN VOR/DME and in position for the initial approach segment for a VOR/DME approach procedure.
- The CVR recording indicates the pilots did not consider any published approach other than the ILS approach. Nevertheless, the pilots did not specifically request the ILS approach.
- The radiotelephone communication methods used by copilot Johnston were sloppy and not compliant with ICAO standards. Specifically, Johnston indicated to ATC he understood and would comply with the ATC directive to descend over the VJN VOR/DME to 9,500 feet. He did this by repeating (part of) the directive at Event118 suggesting to ATC he understood the directive and would comply.
- The pilots did not ask for clarification on the ATC directive to “descend south of the airfield” and put the aircraft on a heading 180o. The aircraft ground track suggested by Frank Petersen in his deposition and in his report titled “REPORT OF INVESTIGATION INTO THE ACCIDENT INVOLVING N204C” (April 24, 1992) has the aircraft flying outbound from the VJN VOR/DME on the 180° radial. This ground track can not be correct since it would put the aircraft 3 nmi east of the crash site at the time the pilots initiated the right turn. The 3 nmi distance could not have been covered in the 25 seconds between initiating the right turn and the impact. (At 230 knots it would take over 46 seconds to cover this distance.) Furthermore, the aircraft would have crashed before it did into the mountains along the 180° radial from the VJN VOR/DME.
- The cockpit conversation at Event179 indicates both pilots saw high terrain 52 seconds before impact. At this time the aircraft was less than 1 nmi from eye-level hills at 4,000 feet and less than 1.7 nmi from a peak at 4,875 feet. The pilots should have realized they were violating IFR approach procedures. (At this time of day the cloud cover near these hills would have been broken with cloud bases above 4,000 feet.) The pilots made no comment to ATC about the terrain or the cloud conditions.
Source: DuPont GII N204C Crash by Roger K. Parsons - Seagull Publishing, Houston, TX

The accident was the consequence of the combination of the following factors:
- Unfavorable weather conditions,
- Wrong runway selection according to wind component and weather,
- Wrong approach configuration,
- The crew failed to initiate a go-around,
- The crew misunderstood ATC instructions.

Due to lack of evidences as the wreckage was not found, the exact cause of the accident could not be determined. However, it was reported that the crew did not send any distress call and it is believed that the accident may have been caused by a sudden and accidental decompression of the cabin.