2014年6月3日星期二

Light aircraft and helicopter came within 100ft of colliding over Liverpool (and the pilot only saw the plane at last minute)



  • Investigators described near-miss in November as a 'very close encounter'

  • Aircraft passed 'right in front of helicopter', said UK Airprox Board report

  • Report also said 'neither pilot saw the other aircraft until very late'

  • Helicopter pilot and observers were looking out window and saw it late on

  • Incident has been categorised as an 'A' risk event - the most serious type

  • Air investigators ruled there was a 'serious risk of a collision'

  • It came just days before helicopter crashed into Glasgow pub, killing 10


By Emma Glanfield



A light aircraft and helicopter came within 100ft of colliding with each over Liverpool city centre, a near-miss report has revealed.


Described by investigators as ‘a very close encounter’, the incident occurred despite the EC135 helicopter being fitted with a Traffic Collision Avoidance System (TCAS).


With no warning being received from TCAS, the twin-engine Piper Chieftain aircraft passed ‘right in front’ of the helicopter ‘at a distance of 100ft or less’, according to the report from the UK Airprox Board (UKAB).


The light aircraft and helicopter came within 100ft of colliding with each over Liverpool city centre in the early evening of November 10 last year

The light aircraft and helicopter came within 100ft of colliding with each over Liverpool city centre in the early evening of November 10 last year



The incident, which occurred in the early evening of November 10 last year, happened just a few days before a Eurocopter EC135 helicopter crashed into a pub in Glasgow, resulting in 10 deaths.


In the report into the Liverpool incident, the UKAB said the pilot and two observers were looking out of the right-hand windows of the helicopter but, being in a right-hand turn, they did not see the other aircraft until it was just passing in front of them.


The other aircraft continued on the same track, descending until it was low over the offshore wind farms just north of Birkenhead.


The report said the helicopter pilot did not recall receiving information from Liverpool air traffic control even though it had taken off from Liverpool airport.


The report went on: ‘The EC135 pilot recalled that around 10 minutes before the airprox [incident] he had called Liverpool air traffic control at least twice to report that he was on-scene, but had not received a response.’


The UKAB added that, believing that the light aircraft’s routing would ensure that it remained well to the west of the helicopter, the tower controller at Liverpool did not pass traffic information to the aircraft pilot.



The twin-engine Piper Chieftain aircraft passed 'right in front' of the helicopter 'at a distance of 100ft or less', according to the report from the UK Airprox Board (file picture, stock image)

The twin-engine Piper Chieftain aircraft passed 'right in front' of the helicopter 'at a distance of 100ft or less', according to the report from the UK Airprox Board (file picture, stock image)



Described by investigators as 'a very close encounter', the incident occurred despite the EC135 helicopter being fitted with a Traffic Collision Avoidance System (file picture, stock image)

Described by investigators as 'a very close encounter', the incident occurred despite the EC135 helicopter being fitted with a Traffic Collision Avoidance System (file picture, stock image)




The report said the helicopter pilot did not recall receiving information from Liverpool air traffic control even though it had taken off from Liverpool airport (pictured)

The report said the helicopter pilot did not recall receiving information from Liverpool air traffic control even though it had taken off from Liverpool airport (pictured)



In addition, the Liverpool radar controller did not pass traffic information to the helicopter pilot due to high workload.


The report said ‘neither pilot saw the other aircraft until very late’, and both estimated the distance between the two aircrafts to be approximately 100ft.


The UKAB said the fundamental cause of the near miss was that, in the absence of traffic information, the aircraft pilot had flown into conflict with the helicopter.


They concluded that the lack of warnings from the helicopter’s Traffic Collision Avoidance System, and the Liverpool tower controller’s misperception of the aircraft pilot’s routing, were contributory factors.


The twin-engine Piper Chieftain aircraft passed 'right in front' of the helicopter over Liverpool city centre (background) before continuing over Birkenhead, Merseyside (foreground)

The twin-engine Piper Chieftain aircraft passed 'right in front' of the helicopter over Liverpool city centre (background) before continuing over Birkenhead, Merseyside (foreground)



The near-miss, which occurred in the early evening of November 10 last year, happened just a few days before a Eurocopter EC135 helicopter crashed into a pub in Glasgow, resulting in 10 deaths (pictured)

The near-miss, which occurred in the early evening of November 10 last year, happened just a few days before a Eurocopter EC135 helicopter crashed into a pub in Glasgow, resulting in 10 deaths (pictured)



The incident was categorised as an ‘A’ risk event - the most serious type – after it was deemed there was a ‘serious risk of a collision’.


The report said: ‘The board agreed that this had been a very close encounter, and that neither pilot had seen the other aircraft in time to take any effective action.’


The UKAB report suggested the helicopter should conduct a test of its Traffic Collision Avoidance System equipment in order to ensure that it was serviceable, but did not conclude as to why it didn’t alert the pilot to the aircraft on the night of the near-miss.











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