By Simon Hradecky, created Thursday, Dec 20th 2018 10:29Z, last updated Monday, May 27th 2019 23:20Z A LATAM Boeing 777-300, registration PT-MUG performing flight LA-8084 from Sao Paulo Guarulhos,SP (Brazil) to London Heathrow,EN (UK) with 341 passengers and 16 crew, was enroute at FL290 about 90nm southwest of Belo Horizonte,MG (Brazil) when the crew decided to divert to Belo Horizonte due to electrical problems, the RAT (Ram Air Turbine) deployed. The crew performed an overweight emergency landing on Belo Horizonte's runway 16 at 01:43L (03:43Z) and became disabled on the runway due to all 12 main tyres having deflated.



The airport reported the airport will be closed until 19:00L.



The airline reported the aircraft diverted due to technical reasons, during landing the tyres of the aircraft were damaged and will need to be replaced before the aircraft can be removed from the runway. All passengers disembarked safely. The removal of the aircraft however has been prohibited until at least 19:00L.



Passengers reported there was a strong odour in the cabin, subsequently the captain announced there was a serious electrical fault prompting the diversion to Belo Horizonte.



Another passenger reported that suddenly all lights and the inflight entertainment system went out, only emergency lights remained. Shortly afterwards the aircraft began the descent towards Belo Horizonte, the crew announced that they had lost all electrical systems and were unable to dump fuel. The landing was hard, emergency services foamed the landing gear. About one hour after landing they were able to disembark via stairs. In the terminal it was being said, that the aircraft had lost all navigation equipment, too, the commander flew the aircraft with the assistance of ATC on the remaining radio for a safe landing. When the crew finally showed up in the terminal lounge, the crew was received with lots of applause, the captain took and answered a lot of questions.



Azul Linhas Aereas ATR-72-212A registrations PR-AKJ and PR-AKD have been dispatched to take about 7 tons of equipment, including the needed hydraulic jack and replacement tyres, to Belo Horizonte.



On Dec 20th 2018 Brazil's CENIPA reported electrical failures occurred in cruise flight, which also compromised other aircraft systems. The crew decided to perform a precautionary diversion to Belo Horizonte for an overweight landing. As result the brakes overheated causing the fuse plugs of the tyres to open and the tyres to deflate. There were no injuries, the aircraft sustained minor damage.



Translated transcript (taken from audio, not the text on the video below) of Portugese communication between Aircraft (AC) and ATC (CTL) when crew indicates the nature and extent of their problems and checks available runway length:



AC: 8084, control

CTL: Radio check

AC: Please confirm runway, it's length is 3 thousand meters?

AC: Please, are we... control? Confirm?

-- unreadable --

CTL: TAM 8084, it's three thousand meters, the runway length

AC: Three thousand meters?

CTL: Three thousand meters ratified, plus 600 paved, 3600 meters in total

AC: OK, pal, thank you. Just, please, remember to call the firefighters. OK, buddy?

AC: The aircraft is very heavy, no way to jettison

AC: Asking for your help. OK, CTL?

CTL: Firefighters, copy

AC: Positive. We're very heavy and the jettison system isn't working either

AC: We're practically without any electrical system working correctly, OK?

AC: So, we have this problem, [which is] a bit serious, OK?

AC: So, please, leave the firefighters prepared.

AC: We're trying here to do the procedure, trying to alleviate the aircraft weight as much as possible

AC: But it's difficult. We're proceeding to the segment and [will] land, OK?

AC: If you could close the runway, that would help us. Thank you.

CTL: Runway is closed already, awaiting your aircraft to land.

CTL: And firefighter support on the ground was requested already.

CTL: Please confirm to Control if you will proceed to land now or if you will do some more holds to burn fuel

AC: No, no. We'll proceed to land, sir.

CTL: Roger and authorized. Procedure ILS Kilo. Report established, TAM 8084.

AC: We don't have any extra information, sir. You inform altitude and vectors, OK?

CTL: Roger. TAM 8084, can you make a right turn to heading 065?

AC: I prefer maintaining this heading for some more time in order to increase the distance, sir.

CTL: Roger. TAM 8084 autorized to maintain the current heading in descent to 7000 feet

AC: Roger, 7000 feet, 8084.



On Dec 22nd 2018 The Aviation Herald learned that the electrical problems started with the failure of the right hand backup generator, as result both transfer and both converter circuit breakers popped leaving all electrical busses unpowered although left and right main generators as well as their generator controls, the APU and the left backup generator remained operative (see ELEC page below, the lines to the L MAIN and R MAIN should be green not white and these symbols should be green, too). As result almost all systems except a few connected to the standby busses lost power, only systems remaining powered are: stand by busses (powering one VHF radio) and emergency lighting, the left inboard and outboard and upper center displays as well as the left CDU remain also powered (according to FCOM via the batteries and/or RAT - with the RAT operating also the right hand - first officer's - displays are being powered).



On Dec 23rd 2018 the airline reported that it was not a failure of power generation but a failure of power distribution. The causes of that failure are now being investigated by CENIPA. After landing, when the crew shut the engines down, power returned, as result the cameras came back online and the crew could see that there was no fire on the landing gear or excessive heat on the brakes, hence the crew queried the need for an emergency evacuation as suggested by emergency services. The captain wanted to avoid an emergency evacuation unless really necessary as the emergency evacuation could have resulted in injuries.



On May 24th 2019 Brazil's CENIPA released a brief update that they found evidence of a short on connector D7232 which connects the right hand backup generator to the right hand converter. The backup converter responded by opening 4 connectors feeding the transfer busses (two transfer bus breakers and two converter circuit breakers).



Related NOTAMs:

J0992/18 NOTAMN

Q) SBBS/QMTCM/IV/NBO/A/000/999/1937S04358W005

A) SBCF

B) 1812201255 C) 1812202130

E) THR 34 DISPLACED 1200M DUE TO ACCIDENT ACFT



J0990/18 NOTAMR J0989/18

Q) SBBS/QMRLC/IV/NBO/A/000/999/1937S04358W005

A) SBCF

B) 1812200617 C) 1812201400

E) RWY 16/34 CLSD DUE TO ACCIDENT ACFT



J0989/18 NOTAMN

Q) SBBS/QMRLC/IV/NBO/A/000/999/1937S04358W005

A) SBCF

B) 1812200539 C) 1812201000

E) RWY 16/34 CLSD DUE TO ACCIDENT ACFT



Metars:

SBCF 200500Z 13008KT 9999 SCT040 22/17 Q1016=

SBCF 200400Z 14004KT 9999 FEW040 22/17 Q1016=

SBCF 200300Z 09009KT 9999 SCT035 22/17 Q1016=

SBCF 200200Z 18002KT 9999 VCTS SCT040 FEW045CB 22/16 Q1017 RETS=

SBCF 200100Z 13008KT 8000 -TSRA BKN035 FEW045CB BKN070 20/16 Q1 018=

SBCF 200040Z 15011KT 4000 TSRA BKN040 FEW045CB BKN070 23/16 Q10 18=

SBCF 200025Z 16010KT 9999 TS BKN040 FEW045CB BKN070 25/18 Q1018=

SBCF 200000Z 19002KT 9999 VCTS SCT040 FEW050CB 26/17 Q1017=



Relevant communication between ATC and Aircraft (see translated transcript above):

https://www.youtube.com/watch?v=SdrHD7RHCs4



The incident electrical page showing all electrical busses without power:





The deployed RAT:





PT-MUG seen the following morning:





The deflated tyres:





Tyre damage:











