Japan Air Lines Flight 123

Photo 7 Minutes Before the Accident.

Serious Crash*This article is a Serious Crash and should not be taken lightly. While all crashes no matter what the incident is, is serious. This one is very serious and should not be joked about*
Japan Air Lines Flight 123 is a crash where a Boeing 747 managed to stay in the air for 30 minutes before falling to the ground. It then crashed its wing onto a small mountain before crashing into another one.

### Wikipedia Information

**Japan Air Lines Flight 123** (Japanese: 日航ジャンボ機墜落事故) was a scheduled domestic passenger flight from Tokyo to Osaka, Japan. On August 12, 1985, the Boeing 747 operating the service suffered a severe structural failure and decompression 12 minutes into the flight. After flying under minimal control for a further 32 minutes, the 747 crashed in the area of Mount Takamagahara, 100 kilometres (62 mi; 54 nmi) from Tokyo.

The aircraft, featuring a high-density seating configuration, was carrying 524 people. The crash killed 15 crew and 505 passengers. Some of the passengers survived the initial impact, but died hours later while awaiting rescue. All four survivors were seriously injured. The crash of Flight 123 is the deadliest single-aircraft accident in aviation history.

Japan's Aircraft Accident Investigation Commission (AAIC), assisted by the U.S. National Transportation Safety Board, concluded that the structural failure was caused by a faulty repair by Boeing technicians following a tailstrike incident seven years earlier. When the faulty repair eventually failed, it resulted in a rapid decompression that ripped off a large portion of the tail and caused the loss of all on-board hydraulic systems, disabling the aircraft's flight controls.

#### Event Sequence

##### 6:27–6:34 p.m.

Heading over the Izu Peninsula at 6:26 p.m., the aircraft turned away from the Pacific Ocean and back towards the shore,  but only turned right far enough to fly a north-westerly course. Seeing that the aircraft was still flying west away from Haneda, Tokyo Control contacted the aircraft again. After confirming that the pilots were declaring an emergency, the controller asked the nature of the emergency. At this point, hypoxia appears to have begun setting in, as the pilots did not respond. Also, the captain and co-pilot asked the flight engineer repeatedly if hydraulic pressure had been lost, seemingly unable to comprehend it.  Tokyo Control contacted the aircraft again and repeated the direction to descend and turn to a 90° heading to Oshima. Only then did the captain report that the aircraft had become uncontrollable. (Tokyo: "Japan Air 124 [sic] fly heading 090 radar vector to Oshima." JAL123: "But now uncontrol." Tokyo: "Uncontrol, roger understood.")

The aircraft traversed Suruga Bay and passed over Yaizu, Shizuoka,  at 6:31:02 p.m. Tokyo Control asked if they could descend, and Captain Takahama replied that they were now descending, stating that their altitude was 24,000 feet (7,300 m). Captain Takahama declined Tokyo Control's suggestion to divert to Nagoya Airport 72 nautical miles (83 mi; 133 km) away, instead preferring to land at Haneda,  which had the facilities to handle the 747. The flight data recorder shows that the flight did not descend, but was rising and falling uncontrollably.  With the total loss of hydraulic control and non-functional control surfaces, the aircraft entered phugoid oscillations lasting about 90 seconds, in which airspeed decreased as it climbed and increased as it fell. The rise in airspeed increased the lift over the wings, resulting in the aircraft climbing and slowing down, then descending and gaining speed again. Almost immediately after the separation of the stabiliser and rudder removed the only means of damping yaw, the aircraft began to exhibit Dutch roll, simultaneously yawing right and banking left, before yawing back left and banking right. At some points the banking motion became very profound, with large arcs of around 50° in cycles of 12 seconds.

Despite the complete loss of control, the pilots continued to turn the control wheel, pull on the control column, and move the rudder pedals up until the moment of the crash. The pilots also began efforts to establish control using differential engine thrust, as the aircraft slowly wandered back towards Haneda. Their efforts were of limited success. The unpressurised aircraft rose and fell in an altitude range of 20,000–25,000 feet (6,100–7,600 m) for 18 minutes, from the moment of decompression until around 6:40 p.m., with the pilots seemingly unable to figure out how to descend without flight controls. This is possibly due to the effects of hypoxia at such altitudes, as the pilots seemed to have difficulty comprehending their situation as the aircraft pitched and rolled uncontrollably. The pilots possibly were focused, instead, on the cause of the explosion they had heard, and the subsequent difficulty in controlling the jet. The flight engineer did say they should put on their oxygen masks when word reached the cockpit that the rear-most passenger masks had stopped working. None of the pilots put on their oxygen masks, however, though the captain simply replied "yes" to both suggestions by the flight engineer to do so. The accident report indicates that the captain's disregard of the suggestion is one of several features "regarded as hypoxia-related in [the] CVR record[ing]." Their voices can be heard relatively clearly on the cockpit area microphone for the entire duration, until the crash, indicating that they did not put on their oxygen masks at any point in the flight.

##### 6:34–6:48 p.m.: Limited control

At 6:35 p.m. the flight engineer responded to multiple (hitherto unanswered) calls from Japan Air Tokyo via the selective-calling system. Having just been informed about the inoperative oxygen masks, the flight engineer voiced the (erroneous) assumption that the R-5 door was broken and informed the company that they were making an emergency descent. Japan Air Tokyo asked if they intended to return to Haneda, to which the flight engineer responded that they were making an emergency descent, and to continue to monitor them.

Eventually, the pilots were able to regain limited control of the aircraft by adjusting engine thrust. In doing so, they were able to dampen the phugoid cycle and somewhat stabilise their altitude. However, given jet engines' inertia and the resulting response time (to changes in throttle), "[s]uppressing of Dutch roll mode by use of the differential thrust between the right and left engines is estimated practically impossible for a pilot." Shortly after 6:40 p.m., the landing gear was lowered using the emergency extension system in an attempt to dampen the phugoid cycles and Dutch rolls further. This was somewhat successful, as the phugoid cycles were dampened almost completely, and the Dutch roll was damped significantly, but lowering the gear also decreased the directional control the pilots were getting by applying power to one side of the aircraft, and the aircrew's ability to control the aircraft deteriorated.

Shortly after lowering the gear, the flight engineer asked if the speed brakes should be used, but the pilots did not acknowledge the request. The aircraft then began a right-hand descending 420° turn from a heading of 040° at 6:40 p.m. to a heading of 100° at 6:45 p.m., flying in a loop over Otsuki, due to a thrust imbalance created from having the power setting on Engine 1 (the left-most engine) higher than the other three engines. The aircraft also began descending from 22,400 feet (6,800 m) to 17,000 feet (5,200 m), as the pilots had reduced engine thrust to near idle from 6:43 to 6:48 p.m. Upon descending to 13,500 feet (4,100 m) at 6:45:46 p.m., the pilots again reported an uncontrollable aircraft. At this time, the aircraft began to turn slowly to the left, while continuing to descend. The thicker air allowed the pilots more oxygen, and their hypoxia appeared to have subsided somewhat, as they were communicating more frequently. The pilots also appeared to be understanding how grave their situation had become, with Captain Takahama exclaiming, "This may be hopeless" at 6:46:33 p.m. At 6:47 p.m., the pilots recognised that they were beginning to turn towards the mountains. Despite efforts by the crew to get the aircraft to continue to turn right, it instead turned left, flying directly towards the mountainous terrain on a westerly heading.

Around 6:50 p.m., a photographer on the ground captured a photograph of the aircraft, which showed that the vertical stabiliser was missing.

##### 6:48–6:55 p.m.: Final loss of control

As the aircraft continued west, it descended below 7,000 feet (2,100 m) and was getting dangerously close to the mountains. Because of the thicker air at lower altitude, the cabin altitude alert momentarily turned off at this time, before resuming for the rest of the flight. The captain briefly ordered maximum engine power to attempt to get the aircraft to climb to avoid the mountains, and engine power was added abruptly at 6:48 p.m., before being reduced back to near idle, then at 6:49 p.m., it was ordered raised again. This greatly excited the phugoid motion, and the aircraft pitched up, before pitching back down after power was reduced. When power was added again, the aircraft rapidly pitched up to 40° and the airspeed dropped down to 108 knots (200 km/h; 124 mph) at 6:49:30 p.m., briefly stalling at 9,000 feet (2,700 m). The captain immediately ordered maximum power at 6:49:40 p.m. as the stick shaker sounded. The aircraft's airspeed increased as it was brought into an unsteady climb. Possibly in order to prevent another stall, at 6:51 p.m., the captain lowered the flaps to 5 units – due to the lack of hydraulics, using an alternate electrical system - in an additional attempt to exert control over the stricken jet. It took 3 minutes and 10 seconds for the trailing edge flaps to reach 5 units. The leading edge flaps except for the left and right outer groups were also extended and the extension was completed at 6:52:39 p.m. From 6:49:03 to 6:52:11 p.m., Japan Air Tokyo attempted to call the aircraft again via the selective-calling radio system. During the entire period, the SELCAL alarm continued to ring, to which the pilots did not react.

The aircraft reached 13,000 feet (4,000 m) at 6:53 p.m., when the captain reported an uncontrollable aircraft for the third time. Shortly afterward, the controller asked the crew to switch the radio frequency to 119.7 for Tokyo Approach. Although the pilots did not acknowledge the request over the radio, they switched frequencies as instructed. Tokyo Approach then contacted the flight via the SELCAL system, briefly activating the corresponding alarm again until the flight engineer responded. At this point, the flight crew requested to be given their position, which, at 6:54 p.m., was reported to the flight as 45 nmi (83 km) northwest of Haneda, and 25 nmi (46 km) west of Kumagaya. At 6:55 p.m., the captain requested flap extension, and the co-pilot called out a flap extension to 10 units, but the flaps had already extended past 5 units at 6:54:30 p.m. and had reached 20 units 1 minute and 2 seconds later. Meanwhile, the aircraft had started banking abnormally towards the right, this may be most likely due to an imbalance in the lift generated by the left and right flaps. Power was increased at the same time. While the flaps continued to extend, a differential thrust setting caused engine power on the left side to be slightly higher than on the right side, adding to the roll to the right.

One minute later, the flaps were extended to about 25 units, the bank angle exceeded 60°, and the nose began to drop. It is likely that the flaps did not extend symmetrically, resulting in a lift imbalance between the left and right wing. Captain Takahama immediately ordered the flaps to be retracted and power was added abruptly, but still with higher power settings on the left engines than on the right. The asymmetric thrust settings continued to increase as the bank angle continued and exceeded 80°. The captain was heard on the CVR desperately requesting for the flaps to be retracted and for more power to be applied in a last-ditch effort to raise the nose. The aircraft continued an unrecoverable right-hand descent towards the mountains as the bank angle recovered to about 70° and engines were pushed to full power, during which the ground proximity warning system sounded. In the final moments, as the airspeed exceeded 340 knots (630 km/h; 390 mph), the pitch attitude leveled out and the aircraft ceased descending, with the aircraft and passengers/crew being subjected to 3 g of upward vertical acceleration.