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DH8D / TOR, en-route, North Sea UK, 2008

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Summary
On 13 October 2008, a DHC-8 Q400 operating in uncontrolled airspace and in receipt of civil radar advisory service was given an avoiding action turn against military traffic but then received and actioned a TCAS RA whilst inside a notified Danger Area as a result of the avoiding action turn. No close proximity to other traffic resulted.
Event Details
When October 2008
Actual or Potential
Event Type
Airspace Infringement, Loss of Separation
Day/Night Day
Flight Conditions VMC
Flight Details
Aircraft BOMBARDIER Dash 8 Q400
Operator Not Recorded
Type of Flight Not Recorded
Intended Destination Newcastle Airport
Take off Commenced Yes
Flight Airborne Yes
Flight Completed Yes
Flight Phase Cruise
ENR
Flight Details
Aircraft PANAVIA Tornado
Operator Not Recorded
Type of Flight Military/State
Take off Commenced Yes
Flight Airborne Yes
Flight Completed Yes
Flight Phase Manoeuvring
MNV
Location
Approx. 27 nm W of Newcastle
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General
Tag(s) Aircraft-aircraft near miss
LOS
Tag(s) See and Avoid Ineffective,
Required Separation not maintained,
Near Miss,
Military Aircraft involved
Safety Net Mitigations
Malfunction of Relevant Safety Net No
TCAS Effective
Outcome
Damage or injury No
Causal Factor Group(s)
Group(s) Aircraft Operation,
Air Traffic Management
Safety Recommendation(s)
Group(s) None Made
Investigation Type
Type Independent

The following description is based on the summary of the report compiled on this AIRPROX by the UK Airprox Board (UKAB).

Description

On 13 October 2008, a DHC-8 Q400 was on heading 056 inbound to Newcastle and in receipt of Radar Advisory Service in Class 'G' Airspace. It was rerouted to avoid Spadeadam Danger Area (EGD510), which was active with an extended vertical limit as published by Notice To Airmen. Approximately 24 nm44,448 m
44.448 km
145,826.772 ft
west of Newcastle, the aircraft was instructed by Newcastle RADAR to stop descent and turn left 010 as Avoiding Action because of unknown traffic passing from right to left and climbing from below the current altitude of the DHC-8. A TCAS TA then occurred followed quickly by a TCAS RA to DESCEND. This was followed and the ATC left turn instruction then acknowledged. After the DHC-8 turned left onto 010 there was another TCAS TA. The ATC avoiding action had resulted in the DHC-8 entering the Danger Area EGD510.

The unknown traffic turned out to be a Tornado GR4 fast jet operating as part of a four aircraft formation. The formation was in receipt of a radar information service from a fighter controller aboard an E3 AWACS aircraft and then was asked to ‘contact’ Spadeadam Range Control. No ATC handover took place between the AWACS and Spadeadam radar controller nor did the AWACS inform the Tornados that their flight information service (FIS) was terminated. The Spadeadam radar controller provided traffic information to the Tormado formation about the DHC-8 as soon as it came on the frequency despite the fact that the crew advised that they were receiving ‘service’ from the AWACS. Neither TCAS nor any other form of collision warning system was fitted on the military jets.

Extracts from the UKAB Review

  • "Service provided by the control team on the AWACS to the Tornado formation during this Exercise would have been limited generally to tactical information about the Exercise mission;
  • The absence of a formal termination of the FIS provided by the Air Defense controller would not be unusual once the jets were inbound to their target area within the confines of the Spadeadam Danger Area;
  • A ‘contract’ had evidently not been established with Spadeadam for a radar service and the Spadeadam Air traffic controller (SPD) had endeavored to clarify this point at an early stage;
  • It was clear that SPD astutely provided accurate and pertinent traffic information to ensure that the GR4 crew was kept closely updated over what was happening so that they might spot the airliner at the earliest opportunity;
  • For their part, the GR4 crew had obtained Range entry clearance and were plainly endeavoring to steer clear of the DHC-8 whilst still trying to salvage their Exercise attack run which needed a fairly precise set-up;
  • Clearly the avoiding action instruction to the DHC-8 crew that resulted in their entry into the danger area unannounced was unwise, but controller […] (representatives) were aware that Newcastle RADAR had little room to manoeuvre so close to the boundary of the Danger Area.

UKAB-determined Cause

The TCAS RA stemmed from the unintentional entry of the airliner into Spadeadam Range as a result of the avoiding action issued by Newcastle RADAR whereupon the DHC-8 crew detected the presence of the jet whilst the GR4 crew were actively avoiding the airliner. The Board therefore concluded that the Cause of this Airprox was a sighting report (TCAS) with no inherent Risk of a Collision.

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