Figure: RKPK ILS/DME 36L, from Korea Aviation Accident Investigation Board Report, Figure 1-10.
There is a lot of blame to go around here, not all of it apparent in the official accident report. The Air China manual classified this Boeing 767 as Category C for straight in approaches and Category D for circling. The crew briefed and began the only available instrument approach: ILS 36L. When the runway was changed to 18R the controller asked the crew for their Approach Category and they responded "Charlie." During their maneuvering they were recorded at 160 knots, well above the Category C maximum speed.
- They thought they were a Category C aircraft but were not. They were cleared the approach based on Category C minimums, but they flew Category D speeds.
- They did not apply an adequate heading offset to fly a downwind with enough offset to allow for a base turn to final, and they did not apply wind drift correction to the downwind heading.
- The captain delayed his base turn 20 seconds beyond what a normal circling maneuver technique would call for.
- They failed to execute the missed approach once losing sight of the runway.
All of those items are noted in the accident report. But if you really want to trace the causes of an aviation mishap, look at the corrective action taken as a result. The job here, after all, is to prevent recurrence. The circling minimums were based on U.S. TERPS which, back then, were much tighter than ICAO standards. Having to maneuver a Boeing 767 within 2.3 nm under Category D minimums is foolhardy. Doing so within 1.7 nm under Category C minimums, in this case, was fatal to most of the passengers on board.
The FAA acknowledged this in 2009, seven years later, by revising TERPS Circling Approach Area criteria. While most U.S. circling approaches are still, as of April 2013, based on the tighter criteria, charts designed after 2011 should be closer to the ICAO standard.
The approach plate in front of you is probably based on the smaller area. You as the pilot can improve your odds by upping your personal visibility minimums. Mine? Three miles gets me to the ICAO minimums and revised TERPS standards. What about your minimum ceiling to circle? We require a go around if outside of Stabilized Approach criteria at 1,000 feet when IMC. If your ceiling minimums are lower than 1,000 feet, you can't do this. We also require a go around if you are not stabilized below 500 feet on a visual or circling approach. If you are fully banked turning on final two miles from the runway, you can't do this.
What follows are quotes from the sources listed below, as well as my comments in blue.
- Date: 15 APR 2002
- Time: 11:21
- Type: Boeing 767-2J6ER
- Operator: Air China
- Registration: B-2552:
- Fatalities: 8 of 11 crew, 121 of 155 passengers
- Aircraft Fate: Destroyed
- Phase: Approach
- Airports: (Departure) Beijing-Capital Airport (PEK/ZBAA), China; (Destination) Busan-Gimhae (Pusan) International Airport (PUS/RKPK), South Korea
[Korea AAR F0201, page 25]
- At 11:06:53, the Gimhae approach controller confirmed that flight 129 received ATIS "Papa." At 11:07:01, the controller informed the crew that runway 36L was in use, and to expect a straight-in approach, which the second officer acknowledged at 11:07:07.
- At 11:08:50, the controller queried flight 129 about its approach category, to which the second officer replied, "Please say again." At 11:08:57, the controller then requested the approach category again, and the first officer stated, "Approach category Charlie" at 11:09:01, but the second officer at first said "What?" and then replied to the Gimhae approach controller with "Charlie, Air China 129" at 11:09:07.
- At 11:08:56, the ATIS was broadcast as "Quebec,"10 but there was no recording of that on the CVR. At 11:09:10, the controller notified flight 129 that the runway was changed to 18R, with winds 210 at 17 kt, and to expect the circling approach to runway 18R.
- At 11:09:21, after receiving the notification from the controller, the first officer announced to other crewmembers, "Circle approach runway 18 right," and the second officer replied to the controller, "Circle approach 18 right, Air China 129."
- At 11:09:30, the controller asked whether the flight 129's approach category was "Charlie" or "Delta," and the captain replied, "Category Charlie." The second officer replied to the controller, "Charlie, Air China 129, Charlie."
The Boeing 767 is a Category Delta aircraft
- From 11:10:19 until 11:12:29, the captain and first officer confirmed the landing runway to be 18R, discussed the circling (minimum descent altitude: MDA) to be 700 ft MSL for runway 18R, visual maneuvering and procedures for exiting the runway and the use of taxiways after landing, and the captain cautioned at 11:12:27, "We won't enlarge the traffic pattern, the mountain is all over that side."
Because this approach was designed using older TERPS criteria, as are most approaches in the United States, it had an unreasonably small circling approach area. More about this: Normal Procedures & Techniques / Circling Approach Area.
- At 11:16:33, the approach controller issued the following clearance: "Air China 129, turn left heading 030, cleared for ILS DME runway 36 left, then circle to runway 18 right, report field in sight." The second officer read back, "Turn left heading 030, cleared [unintelligible] approach 18 right, Air China 129."
- At 11:16:50, the captain said, "Circle to land" and the first officer acknowledged, "Cleared for ILS approach 36 left, and then circle to land 18 right, report runway in sight." The second officer replied, "OK, OK, I understand, circle to land 18 right, turn left 030."
- At 11:18:29, the approach controller instructed flight 129 to report the runway in sight, and at 11:18:39, the captain stated that he had the runway in sight. At 11:18:41, the second officer then reported the runway in sight, at which time, the aircraft altitude was 952 ft, airspeed 158 kt and ground speed 187 kt.
- At 11:18:44, the approach controller instructed, "Air China 129, contact tower one eighteen point one, circle west," but the second officer replied only, "Circle, circle, 18 right, Air China 129" (The frequency change instruction was not read back, and the controller did not point it out). The captain directed, "Disconnect, turn left," and at 11:18:53, the first officer said, "I have control, heading select," and then disconnected the autopilot, and flew manually.
It is unclear why the first officer needed to manually fly the descent. He did not turn the aircraft using a standard rate and to the full heading needed to establish an adequate offset. He did not correct for the "overshooting" crosswind and by the time they were abeam the end of runway 18R, they only had 1.1 NM offset which would not be enough of a diameter for the airplane to complete a base turn to final.
- After there were several beeping sounds at 11:18:55, the aircraft descended to 700 ft at 11:18:57, and the captain said, "OK, maintain 700 ft, watching the altitude." At 11:18:58, the aircraft altitude was 672 ft, airspeed 158 kt, ground speed 182 kt, heading 347 degrees, with a left bank of 16.7 degrees.
- At 11:19:17, the captain said, "20 seconds," and then at 11:19:33, said, "Keep watching the runway." At 11:19:34, the first officer said, "Turning." At 11:19:41, the first officer said, "Engage it again, maintain present altitude 700 ft, heading select," and at 11:19:46, reengaged the autopilot.
- At 11:19:52, the approach controller instructed again, "Air China 129, contact tower, one eighteen one," and the second officer replied, "Contact tower one two one . . . one one eight decimal one, good day, Air China 129." While the primary local controller and approach controller were communicating on the direct line that flight 129 had not contacted the tower, at 11:20:00, the captain asked, "Can you see abeam end of runway?" and at 11:20:01, the first officer replied, "Abeam runway end." At that time, the primary local controller said on the emergency frequency (121.5 Mhz), "This is Gimhae tower on guard, Air China 129, if you hear me, contact one one eight point one."
- At 11:20:02, the captain said, "Timing" to measure for the commencement of turning base. At this time, according to the aircraft track calculated from the FDR data, the aircraft was positioned about abeam the threshold of runway 18R, with an airspeed of 157 kt, ground speed 177 kt and heading 011 degrees.
- At 11:20:13, the first officer said, "The wind is too strong, it is very difficult to fly," and at this time, the second officer reported on the tower frequency 118.1, "Gimhae tower, Air China 129, circle approach 18 right."
- At 11:20:15, 13 seconds elapsed from the start of the time check for turning base, the captain said, "Turning base." At 11:20:17, the captain said, "I have control." At 11:20:19, the primary local controller requested, "Air China 129, report turning base." At 11:20:22, the captain said, "Turning right," and at 11:20:23, the second officer replied to the controller, "Wilco, Air China 129." At 11:20:24, the first officer urged, "Turn quickly, not too late."
- In the mean time, at 11:20:34, the captain said, "Reduce speed," and the first officer replied, "OK." At that time, the airspeed was 158 kt, ground speed 170 kt, heading 350 degrees, and then the airspeed began to reduce.
- [From page 115] At 11:20:37, the captain disconnected the A/P at the heading of 351 degrees and began the delayed base turn, but not until 11:20:42, after approximately 40 seconds elapsed, did the aircraft heading finally pass through 360 degrees toward the south. This was a decisive factor in the aircraft flying outside the circling approach criteria for both categories "C" and "D."
- At 11:20:54, the first officer cautioned, "Pay attention to the altitude keeping," and the captain asked, "Assist me to find the runway." At 11:20:59, the first officer said, "It's getting difficult to fly, pay attention to the altitude."
- At 11:21:02, the secondary local controller queried, "Air China 129, say position now," at 11:21:05, the second officer replied, "Air China 129, on base11." While the second officer was responding, at 11:21:07, the first officer interposed, "Turn on final," and the second officer resumed his reply to the tower, "Turning on final12, and QFE three thousand, Air China 129."
- At 11:21:09, the captain asked, "Have the runway in sight?" but at 11:21:10, the first officer replied, "No, I cannot see out," followed by saying, "Must go around" at 11:21:12. The captain did not respond.
- At 11:21:15, the first officer said, "Pull up! Pull up!" at which time, according to the FDR data, the pitch attitude of the aircraft was increased to a positive 11.4 degrees, while engine thrust did not increase. At this time, the secondary local controller reissued the landing clearance, "Cleared to land 18 right, Air China 129."
- At 11:21:17, there was a sound of impact recorded on the CVR. The aircraft impacted the mountain located on a bearing of 354 degrees from the airport, about 4.6 km from the threshold of runway 18R, at an elevation of 204 meters MSL. The last data about the status of the aircraft recorded on the FDR showed altitude 704 ft, airspeed 125 kt, ground speed 133 kt, heading 149 degrees, right bank 26.8 degrees, and pitch angle 11.4 degrees.
Figure: Circling Approach Radar Track, from Korea Aviation Accident Investigation Board Report, Figure 1-7.
[Korea AAR F0201, page 17]
- The flight crew of flight 129 performed the circling approach, not being aware of the weather minima of wide-body aircraft (B767-200) for landing, and in the approach briefing, did not include the missed approach, etc., among the items specified in Air China's operations and training manuals.
- The flight crew exercised poor crew resource management and lost situational awareness during the circling approach to runway 18R, which led them to fly outside of the circling approach area, delaying the base turn, contrary to the captain's intention to make a timely base turn.
The approach was designed under older TERPS criteria with a 1.7 NM radius for Category C and 2.3 NM radius for Category D aircraft. The aircraft crashed at a point about 2.48 NM from the threshold of runway 18R. Had the approach been designed under ICAO rules, or under newer TERPS rules, the radius would have been much wider but so would the visibility required to fly the circling approach. All of that notwithstanding. the downwind was flown too close to the runway to make the turn even under optimal conditions.
- The flight crew did not execute a missed approach when they lost sight of the runway during the circling approach to runway 18R, which led them to strike high terrain (mountain) near the airport.
- When the first officer advised the captain to execute a missed approach about 5 seconds before impact, the captain did not react, nor did the first officer initiate the missed approach himself.
[Korea AAR F0201, page 18]
- Instrument approach chart used by the flight crew of flight 129 did not depict the high terrain north of the airport.
- Flight 129 was flown between 150 and 160 kt on the downwind leg, which exceeded the maximum speed of 140 kt of Gimhae airport's circling approach category "C," and the width of the downwind leg was narrower than normal, for which corrective actions were inappropriate.
- The differences between the ICAO and Korean criteria for the flight procedure establishment of Gimhae airport were not described in the ROK AIP effective at the time of the accident.
Korea Aviation Accident Investigation Board Report, AAR F0201, Controlled Flight Into Terrain, Air China International Flight 129, B767-200ER, B2552, Mountain Dotdae, Gimhae, April 15, 2002