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Enhanced weather disruption management for runway 22

4 juillet 2016 - Transports
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Adverse weather situations affecting Nice airport principally occur when runway 22 is in use. Westerly landings do not always rhyme with great sunshine and strong head winds.

Such met events are linked to the specific topology of the airfield, mountains being so close to the coast line. Visibility or cloud base height issues are frequently observed in the bay of Nice. Airport accessibility can thus become at stake as the operating minima for the existing procedures are high.
 

What is the procedure followed by ATC when bad weather occurs and runway 22 is in use ?

As a foreword, it is important to remember that VOR B and RNAV D arrival procedures cannot be simultaneously in use as trajectories end out to be conflicting.

The runway capacities shown are baselines and should not be considered as systematically applied values. Real time conditions may require a lower runway capacity and adjusted regulation rates. Such assessment is based on the expertise of both Nice tower managers and Marseille ACC flight management unit.

Besides, during adverse conditions, applied flow regulation rates are very often below the possible runway capacity at that time, to ensure that it will never be exceeded ; an utmost safety objective during particularly uncomfortable situations for flight crews.

When RNAV D is the only possible approach procedure to be flown, the aircraft flying towards the airfield will be asked their RNAV capability and whether they intend to try the RNAV D procedure.

Safety in mind

  • As the weather gets worse, missed approaches and go arounds are to be expected.
  • For those non equipped for PBN approaches, ATC will provide assistance and vectors towards either the closest holding pattern within Nice TMA or their alternate if no accurate forecast can be provided at the time of decision.
    The transitioning phase consists in the real time management of inflight aircraft (holding, diversions, missed approaches) explaining the need for the application of a temporary “zero rate” Click here to know what does a “zero rate” stand for.
  • When strong westerly winds blow, there may be turbulence on short final 22R that could lead to a missed approach. In this case, the traffic may be exceptionally entirely carried on RWY 22L with a runway capacity of 20/60.

Safety has been recently improved thanks to the recent publication of implementation conditions for VOR B procedure : ceiling ≥ 1500ft and visibility ≥ 8km. Indeed, these new conditions provide what can be considered as an ATC buffer zone leaving enough time for a safe transition towards RNAV D procedure.

Towards “GNSS only” operations

Coordination with the NM is essential to study the best rate to apply following the “zero rate” that could be requested during the transition from VOR B to RNAV D operations. The traffic regulation decided upon will provide a seamless flow of arrival to the airfield with no discontinuation once the inflight aircraft would have been dealt with.

For those which have not yet left their airfield of origin, the Network Manager will sort out equipped aircraft from non-equipped aircraft out of the list of flights operating to Nice in the hours to come. The planes equipped to join the platform will be issued a departure slot in accordance with the runway capacity applied at that time. All other aircraft would have to wait until the VOR B procedure can again be in use.

Recovery process and traffic prioritization

At the early stage of the recovery process, priority would be naturally given to the planes that had been forced to divert.
Aircraft operators would usually choose Marseille, Toulon or Genoa as alternates. These aircraft being close from Nice airport, it shall be considered whether they could be relieved from ongoing regulations to join the airfield as soon as ready and bridge the gap before the flow of arrivals starts again.

Obtaining a realistic weather improvement assessment

Increasing the regulation rate and going back to the nominal runway capacity are progressively done considering the adverse weather events ‘degree of predictability.

How to tackle runway 22 accessibility issue when the weather is bad ?

RNAV equipment is a strong marker for improved accessibility as current operating minima are lower for RNAV D than for VOR B, especially in terms of visibility.

« RNP approaches shall progressively become the procedures to be systematically in force at Nice airport, emphasizing the need to promote the optimal on-board equipment principle among the aeronautical community as a tangible means to improve accessibility” DSNA PBN Program Director

What projects in the long term ?

In collaboration with Air France and Airbus, Nice has recently carried out a SESAR large scale demo called RISE. This demo aims at assessing a RNP AR procedure (Required Navigation Performance Authorisation Required) for runway 22.


© Photothèque STAC / Véronique PAUL - Graphix Images
The RNP AR procedure for runway 22 is a fully coded procedure, all the way to the runway threshold, with vertical guidance available for the entire descent. The first part of the trajectory can be considered as an overlay of RWY 22 RNAV D, followed by a satellite guided curved leg after the Final Approach Fix (FAF), known as Radius to Fix (RF).
Live trials have notably shown significant safety improvements thanks to the vertical guidance provided and reliability for the base turn inside the bay
 

RNP AR MINIMA

Visibility 1 700 meters Ceiling 390 ft
“Pilots found the approach very comfortable and were able to fly continuous descents thanks to the cooperation of ATC. RISE procedure brought proven improvements compared to current situation for runway 22 : a fully coded procedure, a coded missed approach…and very attractive minima”. Nice Chief Pilot – CDB A320

DSNA is currently assessing the technical matters that still remain. The objective is to ensure publication and operational implementation for both runways 22 at Nice airport. This first publication for France is expected to be the milestone of further RNP AR studies, designs and implementations.

Be equipped for RNP AR operations and benefit from shorter fuel efficient flight paths and improved runway accessibility. RNP AR procedures require being RNP AR Radial to Fix & GNSS equipped
 

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