China Airlines B738 at Toyama and Nagoya on Jul 8th 2018, fuel emergency

Last Update: January 30, 2020 / 18:45:51 GMT/Zulu time

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Incident Facts

Date of incident
Jul 8, 2018

Classification
Incident

Airline
China Airlines

Flight number
CI-170

Departure
Taipei, Taiwan

Destination
Toyama, Japan

Aircraft Registration
B-18667

Aircraft Type
Boeing 737-800

ICAO Type Designator
B738

A China Airlines Boeing 737-800, registration B-18667 performing flight CI-170 from Taipei (Taiwan) to Toyama (Japan) with 155 people on board, attempted 2 approaches to Toyama's runway 02 but needed to go around twice. The aircraft subsequently attempted an approach to runway 20 but again needed to go around. The crew decided to divert to Nagoya (Japan), climbed to FL240 and was on approach to Nagoya's Chubu Airport when the crew declared emergency reporting being low of fuel. The aircraft continued for a safe landing on Nagoya's runway 18 about one hour after the first go around.

Japan's Ministry of Transport reported the occurrence was rated a serious incident (editorial note: suggesting the aircraft landed with less than the required final fuel reserve remaining) and dispatched two accident investigators on site.

The occurrence aircraft remained on the ground in Nagoya for about two hours, then continued to Toyama and performed the return flight.

On Jan 30th 2020 the JTSB released their final report concluding the probable cause of the serious incident was:

It is highly probable that the serious incident was caused by the landing conducted in the situation that the remaining fuel quantity was close to FINAL RESERVE after emergency communications.

It is somewhat likely that consuming a fairy quantity of the reserve fuel when attempting to land at the destination airport multiple times contributed to the remaining fuel quantity at landing, which was close to FINAL RESERVE. Besides, it is highly probable that the aircraft was not in shortage of fuel since the remaining fuel quantity at the time of landing was not below FINAL RESERVE.

The JTSB described the sequence of events:

On July 8, 2018 at 9:09 in Japan Standard Time (JST: UTC+9 hours; unless otherwise noted, all times are indicated in JST in this report on a 24-hour clock), the Boeing 737-800, registered B18667, operated by China Airlines, with the captain sitting in the left seat as PF*1 and the first officer sitting in the right seat as PM*1, took off from Taiwan Taoyuan International Airport in Taipei, Taiwan. The flight crew, before approaching Toyama airport, performed approach briefing after obtaining weather information of Toyama airport and got prepared for landing on runway either 20 or 02, whichever the aircraft may land on.

The aircraft conducted a circling approach to runway 02 in the first attempt of approaching. The aircraft executed go-around at 12:00:00 because the descent rate exceeded the stable approach criteria stipulated in the FOM (Flight Operation Manual) of the operator affected by a gusty wind at an altitude of about 400 ft. The remaining fuel quantity of the aircraft at the time of the go-around was about 8,600 lb.

The aircraft conducted the second circling approach to runway 02 again. Then, the aircraft executed go-around again at 12:14:40 because the approaching speed at an altitude of about 100 ft exceeded the criteria. The remaining fuel quantity at the time of the second go-around was about 7,300 lb.

The aircraft conducted the third approaching to runway 20 because a wind condition was suitable, and an expected remaining fuel quantity, if the third approach ended in go-around, exceeded the total of the fuel quantity needed to fly to the alternate airport and the final reserve fuel quantity. However, the aircraft executed go-around again at an altitude of about 1,000 ft at 12:27:47 because the descent rate exceeded the criteria affected by a strong tail wind. The remaining fuel quantity at the time of the go-around was about 6,000 lb. The landing at Toyama airport was abandoned and the change of the destination airport to Chubu Centrair International Airport (hereinafter referred to as “Chubu Airport”) was informed Toyama airport traffic control tower (hereinafter referred to as “Toyama Tower”). Toyama Tower instructed the aircraft to contact Tokyo ACC.

At 12:31:35, the aircraft called in Tokyo ACC and requested the change of the destination airport to Chubu Airport.

At 12:33:04, Tokyo ACC informed the aircraft that it conducted radar identification and the location of the aircraft was 12 nm north of Toyama VOR/DME (TOE), and it instructed the aircraft to climb to FL*2150.

At 12:36:11, the aircraft conducted an emergency communication (communication commencing with urgent signal of PAN-PAN, PAN-PAN, PANPAN) to Tokyo ACC and requested clearance to Chubu Airport. According to the flight crew, he informed Tokyo ACC that the remaining fuel quantity was in a tight situation before this emergency communication, however, he did not receive an explicit response. On the other hand, according to the ATC communication records, transmission that was said to have been conducted prior to the emergency communication was not confirmed. Furthermore, emergency communication from the aircraft at this time was in low and muffled and the voice was unclear overlapped by back noises. Tokyo ACC was unable to hear the transmission and asked for the call sign (flight number) again. The aircraft responded with the call sign and requested clearance to Chubu Airport. The transmission sent again by the aircraft this time included the call sign and request for clearance, and did not include the urgent signal. Taking the busy situations in the airspace into consideration, Tokyo ACC intended to issue clearance after ATC communications with other aircraft calmed down, and commenced radar vectoring of the aircraft firstly at magnetic heading of 140 o in order to let it join the flow of other arriving aircraft from the northern Japan to Chubu Airport and Kansai-Osaka Airport.

The flight crew wondered why the aircraft was instructed to fly at the magnetic heading of 140 o because Chubu Airport was located in southern direction from the aircraft. Besides, flight log (flight route planned prior to the departure) showed that flight route to Chubu Airport, the alternate airport, was via Komatsu VORTAC (KMC), which was in the opposite direction from the flight instruction of 140 o magnetic heading.

At 12:36:49, the aircraft conducted the second emergency communication, and simultaneously requested short cut to Chubu Airport due to running short remaining fuel quantity (see Figure 1 and 2 (ii)). ATC communication records showed that the emergency communication from the aircraft at this time was again in low and muffled and the voice was unclear. Tokyo ACC was unable to recognize the urgent signal, and again asked the aircraft for its desired flight route to Chubu Airport, but the aircraft reverted with request to repeat the message again. Then, Tokyo ACC instructed the flight at magnetic heading of 140 o again. The aircraft responded saying that they understood the instruction.

The flight crew was concerned about remaining fuel quantity that was running short because the flight at the magnetic heading of 140 o was in the direction of the airspace over mountainous areas.

At 12:37:29, Tokyo ACC instructed the aircraft to climb to FL230 to obtain better condition of communications because communications from the aircraft were overall hard to hear and partially unclear.

At 12:41:29, the aircraft conducted the third emergency communication and informed that remaining fuel quantity was getting critical because the remaining fuel quantity at the time of arrival to Chubu Airport calculated by Flight Management Computer (FMC) became close to the final reserve fuel quantity if the aircraft directly flew to the airport. The Controller recognized by this emergency communication that the aircraft was in an emergency and confirmed the emergency status with the aircraft. The emergency communication from the aircraft at this time was clear.

At 12:42:40, the aircraft sent the distress communication (communication commencing with distress signal of MAYDAY, MAYDAY, MAYDAY). Tokyo ACC gave the priority on the air traffic control to the aircraft and instructed to fly directly to Chubu Airport.

The flight crew could not recall whether they informed, prior to the emergency communication, the MINIMUM FUEL (detailed in 2.7 (3)) stipulated to conduct in the FOM in flight from Toyama airport to Chubu Airport. It could not be confirmed from ATC communication records whether the aircraft informed MINIMUM FUEL in flight from Toyama airport to Chubu Airport.

The aircraft landed at Chubu Airport at 13:10 with the priority on the air traffic control being granted. The remaining fuel quantity after landing was 2,480 lb.

The JTSB analysed:

In this serious incident, the aircraft conducted the emergency communications and the distress communication based on the judgment of the critical fuel status. It is probable that the flight crew conducted the distress signal in order to gain the attention to the situation of critical fuel from Tokyo ACC. However, the terms of “PAN-PAN, PAN-PAN, PAN-PAN” and “MAYDAY, MAYDAY, MAYDAY” were used, not “MINIMUM FUEL” and “MAYDAY, MAYDAY, MAYDAY FUEL” that are regulated to use for the case of low fuel situation by FOM of the operator that conforms to ICAO regulations.

The terms in accordance with international standard and FOM that conforms to international standard should be used, because it is necessary to communicate accurately and promptly any time in air traffic control communication.

Metars Toyama:
RJNT 080500Z 35008KT 9999 FEW020 SCT130 BKN/// 30/23 Q1013=
RJNT 080400Z 01010KT 340V050 9999 FEW015 SCT100 31/20 Q1013=
RJNT 080334Z 35011KT 9999 FEW010 SCT090 32/20 Q1013 RMK 1CU010 4AC090 A2992=
RJNT 080300Z 36009KT 9999 FEW010 SCT090 28/22 Q1013=
RJNT 080200Z 32004KT 270V030 9999 FEW010 SCT100 27/23 Q1013=
RJNT 080100Z 36007KT 330V050 9999 FEW010 SCT020 BKN080 25/21 Q1013=
RJNT 080000Z 03005KT 360V070 9999 VCSH FEW005 BKN010 BKN015 23/22 Q1013=

Metars Nagoya:
RJGG 080600Z 16011KT 9999 FEW015 BKN/// 29/24 Q1014 NOSIG=
RJGG 080530Z 15012KT 9999 FEW015 SCT070 BKN/// 30/24 Q1014 NOSIG=
RJGG 080500Z 15012KT 9999 FEW015 BKN/// 29/24 Q1014 NOSIG=
RJGG 080430Z 14012KT 9999 FEW015 SCT/// 29/24 Q1014 NOSIG=
RJGG 080400Z 16013KT 9999 FEW015 SCT/// 29/25 Q1014 NOSIG=
RJGG 080330Z 16011KT 9999 FEW015 SCT/// 29/24 Q1014 NOSIG=
RJGG 080300Z 16013KT 9999 FEW015 29/25 Q1014 NOSIG=
RJGG 080230Z 17011KT 9999 FEW015 29/25 Q1014 NOSIG=
RJGG 080200Z 16010KT 9999 FEW010 SCT020 29/26 Q1014 NOSIG=
RJGG 080130Z 16009KT 9999 FEW010 SCT020 29/25 Q1014 NOSIG=
RJGG 080100Z 15009KT 9999 FEW010 SCT015 28/25 Q1014 NOSIG=