[Peetwo]

Chalk & Cheese: TSIB(S) vs ATSB

Via Accidents OS:

Singapore Airlines Flight 321: Aviation accident and incident

There are many MSM and social media articles and news segments that have been running on the SQ Flight 321 CAT occurrence but IMO one of the more factual and less dramatised articles, is the following from Reuters:

The mechanics of turbulence
What happened to Singapore Airlines flight SQ321 and why?

By Adolfo Arranz, Vijdan Mohammad Kawoosa, Sudev Kiyada, Han Huang, Mariano Zafra and Simon Scarr
Published May 23, 2024  04:30 AM GMT+10

Plus from blancoliro, via YouTube:

Hmm...wonder how long it took for the CAAS SSP to click into gear -    

SINGAPORE STATE SAFETY PROGRAM

I'd say it took the Singaporean aviation authorities, including the Transport Safety Investigation bureau, a matter of hours to kick into gear and then a  mere 8 days for a preliminary summary report to be published - WOW! 

Via Oz Aviation:

PRELIMINARY REPORT RELEASED INTO TURBULENCE-HIT SINGAPORE FLIGHT
written by Jake Nelson | May 30, 2024

A preliminary report from Singapore’s Transport Safety Investigation Bureau (TSIB) has outlined the harrowing turbulence faced by passengers on Singapore Airlines flight SQ321.

43 passengers and crew were injured and an elderly British passenger suffered a fatal heart attack when the flight from London to Singapore hit severe turbulence last week, forcing it to divert to Bangkok. 56 Australians were on board, at least eight of whom were hospitalised.

The investigation team, comprising TSIB investigators working alongside US representatives from the National Transportation Safety Board (NTSB), Federal Aviation Administration (FAA) and Boeing, has pieced together the sequence of events based on data from the 777-300ER’s two black boxes.

According to the flight data recorder (FDR) and cockpit voice recorder (CVR), the flight began to experience a “slight vibration” at 07:49:21 (UTC) on 21 May, when it was passing over Myanmar at around 37,000 feet.

“Around the same time as the onset of the slight vibration, an uncommanded increase in aircraft altitude, reaching a peak of 37,362 ft, was recorded. In response to this uncommanded altitude increase, the autopilot pitched the aircraft downwards to descend back to the selected altitude of 37,000 ft,” the investigators wrote.

“In addition, the pilots observed an uncommanded increase in airspeed which they arrested by extending the speed brakes. While managing the airspeed, at 07:49:32 hr, it was heard that a pilot called out that the fasten seat belt sign had been switched on.”

The investigators believe that the increase in altitude was most likely due to an updraft, and that “the autopilot was engaged during this period”.

“At 07:49:40 hr, the aircraft experienced a rapid change in G as recorded vertical acceleration decreased from +ve 1.35G to negative (-ve) 1.5G, within 0.6 sec. This likely resulted in the occupants who were not belted up to become airborne,” they wrote.

 
Via the Singapore MOT website:

Transport Safety Investigation Bureau Preliminary Investigation Findings of Incident Involving SQ321
29 May 2024 - Press Releases

1.    The Transport Safety Investigation Bureau of Singapore (TSIB) has extracted the data stored in the flight data recorder (FDR) and cockpit voice recorder (CVR) of flight SQ321.

2.    The investigation team comprises TSIB investigators and United States representatives, from the National Transportation Safety Board (NTSB), Federal Aviation Administration (FAA) and Boeing.

3.    The investigation team has compiled a chronology of events based on preliminary analysis of the data from FDR and CVR:

a.    SQ321 departed London on 20 May 24 and the flight was normal prior to the turbulence event. At 07:49:21 hr (UTC) on 21 May 24, the aircraft was passing over the south of Myanmar at 37,000 ft and likely flying over an area of developing convective activity. The Gravitational force (G), recorded as vertical accelerations, fluctuated between positive (+ve) 0.44G and +ve 1.57G for a period of about 19 sec. (This would have caused the flight to begin to experience slight vibration).

b.    Around the same time as the onset of the slight vibration, an uncommanded increase in aircraft altitude, reaching a peak of 37,362 ft, was recorded. In response to this uncommanded altitude increase, the autopilot pitched the aircraft downwards to descend back to the selected altitude of 37,000 ft.  In addition, the pilots observed an uncommanded increase in airspeed which they arrested by extending the speed brakes. While managing the airspeed, at 07:49:32 hr, it was heard that a pilot called out that the fasten seat belt sign had been switched on.

c.    This uncommanded increase in aircraft altitude and airspeed mentioned in (b) are most likely due to the aircraft being acted upon by an updraft (the upward movement of air). The autopilot was engaged during this period.

d.    At 07:49:40 hr, the aircraft experienced a rapid change in G as recorded vertical acceleration decreased from +ve 1.35G to negative (-ve) 1.5G, within 0.6 sec. This likely resulted in the occupants who were not belted up to become airborne.

e.    At 07:49:41 hr, the vertical acceleration changed from -ve 1.5G to +ve 1.5G within 4 sec. This likely resulted in the occupants who were airborne to fall back down.

f.    The rapid changes in G over the 4.6 sec duration resulted in an altitude drop of 178 ft, from 37,362 ft to 37,184 ft. This sequence of events likely caused the injuries to the crew and passengers.

g.    In the midst of the sequence of rapid changes in G, recorded data indicated that the pilots initiated control inputs to stabilise the aircraft, disengaging the autopilot in this process. The pilots manually controlled the aircraft for 21 sec and reengaged the autopilot at 07:50:05 hr.

h.    The recorded vertical acceleration showed more gradual fluctuations over the next 24 sec, ranging from +ve 0.9G to +ve 1.1G, while the aircraft returned to 37,000 ft at 07:50:23 hr.

i.    After the pilots were informed by the cabin crew that there were injured passengers in the cabin, the decision was made to divert to Suvarnabhumi Airport, Bangkok, Thailand. On the way to Bangkok, the pilots requested for medical services to meet the aircraft on arrival.

j.    Approximately 17 minutes after the turbulence event, at 08:06:51 hr, the pilots initiated a normal, controlled descent from 37,000 ft and the aircraft reached 31,000 ft at 08:10:00 hr. The data showed that the aircraft did not encounter further severe turbulence during this diversion, and touched down in Suvarnabhumi Airport at 08:45:12 hr.

4.    Investigations are ongoing.

Compare that to this from Popinjay HQ..

From the ATSB's 'Occurrence category taxonomy and terminology' webpage the ATSB definition for an 'aircraft accident' (although recently updated - 1 Jan 2023???) still includes a provision for a serious injury:
 

A person suffers a fatal aircraft-related injury in relation to the operation of the aircraft; or

A person suffers a serious aircraft-related injury in relation to the operation of the aircraft;

This is the current ICAO Annex 13 definition:

An accident is defined as:

An occurrence associated with the operation of an aircraft which, in the case of a manned aircraft, takes place between the time any person boards the aircraft with the intention of flight until such time as all such persons have disembarked, or in the case of an unmanned aircraft, takes place between the time the aircraft is ready to move with the purpose of flight until such time as it comes to rest at the end of the flight and the primary propulsion system is shut down, in which:
a) a person is fatally or seriously injured as a result of:

• being in the aircraft, or
  
• direct contact with any part of the aircraft, including parts which have become detached from the aircraft, or
  
• direct exposure to jet blast,
  

except when the injuries are from natural causes, self-inflicted or inflicted by other persons, or when the injuries are to stowaways hiding outside the areas normally available to the passengers and crew; or..

Unfortunately there is a notified difference to the ICAO SARP definition for an accident:

"..Australia requires reporting of ‘transport
safety matters’, which, through definitions and
reporting requirements in the Transport Safety
Investigation Act 2003 and Transport Safety
Investigation Regulations 2003 result in
matters being reported which are equivalent to
those contained in the Annex 13 definition of
an accident.. The Annex 13 definition of an
accident is used for classifying reports in the
Accident Investigation Authority’s database.."

Not sure how that changes matters from a legal POV but IMO an occurrence involving a HCRPT aircraft, where a 'serious injury' has subsequently occurred due to that occurrence, should require the ATSB to define that event as an accident and therefore should necessarily precipitate an accident investigation within a matter of hours of being notified of the occurrence.
 
Therefore it is with interest I read the following Robyn Ironside article, via the Oz:

Turbulent Qantas flight under investigation after cabin crew member was badly hurt

May 31 2024

Qantas is being investigated over a turbulence episode on a flight from Sydney to Brisbane on May 4, in which a flight attendant suffered a broken ankle.

The Australian Transport Safety Bureau has only just flagged the investigation, almost four weeks after the incident which occurred on a Boeing 737-800 at about 9000ft.

It’s understood the decision to investigate was made after further information was gathered from Qantas.

According to the ATSB investigation brief, seatbelt signs were turned on but crew members were not yet seated when the turbulence struck.

“One of the cabin crew members sustained a serious ankle injury,” the ATSB said.

“The flight crew notified air traffic control and an ambulance crew was waiting for the aircraft on arrival.”

A Qantas spokeswoman said they were co-operating with the ATSB investigation.

“The aircraft experienced a brief, sudden turbulence event while descending into Brisbane,” said the spokeswoman.

“The seatbelt sign was on and all passengers were seated but cabin crew were in the process of taking their seats for landing when the turbulence event occurred.”

The injured flight attendant was treated on board by fellow crew members and an on-board medical professional.

“The aircraft landed normally in Brisbane and paramedics boarded the aircraft to attend to the injured crew member,” the spokeswoman said.

“We appreciate this may have been an unsettling experience for customers and we thank them for their co-operation.”

Witnesses and “involved parties” would be interviewed as part of the ATSB investigation, which was also expected to examine maintenance records and review recorded data.

A report was expected by the end of the year.

The investigation follows two episodes of severe turbulence on overseas flights, involving Singapore Airlines and Qatar Airways in the last week.

In the Singapore Airlines incident, one man died and scores of others were seriously injured when the Boeing 777-300ER experienced drastic fluctuations in vertical acceleration over Myanmar on May 21.

A preliminary report said the aircraft was approaching an area of developing bad weather at the time, and an updraft caused the sudden upward movement.



Days later, a Qatar Airways flight from Dublin to Doha struck unexpected turbulence over Turkey, causing injuries to 12 passengers and crew.

Eight of those were taken to hospital on arrival.

Despite the spate of turbulence-related events, there was no firm evidence to suggest turbulence episodes were becoming more severe or more frequent.

The ATSB’s own occurrence database showed only three turbulence events involving Australian aircraft had been reported in 2024.

A quick review of the ATSB AAI database webpage indicates the following:

Summary

The ATSB is investigating a turbulence event involving Boeing 737, VH-VYK, being operated on flight QF520 from Sydney to Brisbane on 4 May 2024.

It was reported that as the aircraft was passing 9,000 ft on descent with the seatbelt sign on and cabin crew not yet seated, the aircraft encountered turbulence. One of the cabin crew members sustained a serious ankle injury. The flight crew notified ATC and an ambulance crew was waiting for the aircraft on arrival.

The evidence collection phase of the investigation will involve interviewing witnesses and involved parties, examination of maintenance records, retrieving and reviewing recorded data, and the collection of other relevant information.

Should a critical safety issue be identified during the investigation, the ATSB will immediately notify relevant parties, so that appropriate safety action can be taken.

A final report will be published at the conclusion of the investigation.

This investigation is listed as an 'occurrence investigation' with a level of 'Short' and was initiated 3 weeks after the occurrence would have been mandatorily 'immediately' reported by Qantas - WTD?? 

Like CHALK and CHEESE? - Yep!   

MTF...P2 

PS: I note that there is no accompanying bollocks media statement accompanying this accident investigation - Err..I wonder why??