Review of Policy: Non-plannable Level in the NAT-Region

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Review of Policy: Non-plannable Level in the NAT-Region

54TH ANNUAL CONFERENCE, Sofia, Bulgaria, 20-24 April 2015

WP No. 91

Review of Policy: Non-plannable Level in the NAT Region

Presented by TOC

Summary

This working paper makes a review of the current IFATCA policy with regards to the use of nonplannable levels in the NAT-region. The policy was adopted in 1999 and a recent review has shown that this particular policy statement does not reflect (anymore) the operational traffic handling of the NAT-region. After a review of the current ATC-situation in regards to traffic handling of unforeseen and non-plannable events in the NAT-region, this WP is proposing a deletion of this policy statement (as it is outdated and does not reflect any more the operational reality of the NAT-region).

Introduction

1.1 This particular IFATCA-policy regarding the retention of a non-flight plannable level was adopted in 1999 in Santiago de Chile (at the IFATCA World Conference of the year 1999).

1.2 The background was that ICAO was in the process of starting the implementation of RVSM in the NAT-region (North Atlantic region) and so the IFATCA-delegates in Chile thought that it was necessary to keep some “safeguards”. One way to achieve this was by keeping free given Flight Levels, if needed – e.g. for the handling of contingency and/or unexpected situations.

Discussion

2.1. Back in 1999, before the implementation of RVSM in the NAT-region the delegates of IFATCA thought that it was necessary that certain safeguards are being put in place to make sure that ATC is enabled to handle aircraft safely in the NAT-region – even in special or contingency-situations. This, as the aircraft would be flying much more packed (being separated much closer to each other) over the NAT-region, once RVSM would be implemented. The NAT-region is an area where no ATS surveillance – for most of the time – is available.

2.2. This is the reason why – back in 1999, at Santiago de Chile – the following policy statement was adopted by the IFATCA delegates:

Within the NAT region where RVSM is in operation, FL 300 would be established as a nonflight plannable level as part of the “in-flight emergency contingency” procedures as they apply to the Organised Track System.

 

2.3. The following explanation was then added – at little bit later in the IFATCA-Manual (for this particular policy statement):

ATS 3.11 THE USE OF NON-FLIGHT-PLANNABLE LEVELS IN THE NAT REGION FOR CONTINGENCY

There is evidence that there is an identifiable number of incidents which require an aircraft to divert or for ATC to intervene which does not require a descent out of the NAT track structure.

 

Comments received from an operational NAT-expert working the NAT-region (in late 2014) said the following: Operational experience has shown that the blockage of FL 300 (as plannable Flight Level) is not at all required. This, as the in-flight contingencies can be quite easily handled without problems – so without the blockage of, or the use of FL 300 (as reserved FL).

2.4. Fact is that very strict contingency procedures have been established for the NAT-region and they do use (mainly) 500 feet vertically as an emergency intermediate (contingency) level. Flight levels 300 and/or FL 280 are both also used on numerous occasions for aircraft that are either too heavy or just not (yet) willing to accept any higher flight level. This is normal day-to-day ATC-life for the NAT-region.

2.5. Flight Level 290 is also used extensively for eastbound aircraft routing close to, or below, the Organized Track Structure (OTS) of the NAT-region. NAT operational experts report as well that in the vast majority of the time the NAT CONTINGENCY PROCEDURES will perfectly cater for safe solutions and/or offer options for such special cases.

2.6. According to these same NAT-experts the only decision that the ATCOs have to make are: “AT WHAT SAFE LEVEL WILL THE AIRCRAFT BE ABLE TO ROUTE DIRECT TO ITS DIVERSION AIRFIELD?” This can usually turn-out to be normally FL 290, or FL 270. This is all dependent on the traffic situation at the time the occurrence takes place.

2.7. But it is for sure not necessary to reserve FL 300 as “NON FLIGHT PLANNABLE LEVEL” for the NAT-region. This was the conclusion of the OPS-experts of the NAT-region. They believe that this limitation is not only very restrictive, but also operationally “unnecessary”. There are many other options to handle “Contingencies” in the NATregion – and they are well sufficient.

Conclusions

3.1 Operational experience has shown that this particular IFATCA policy statement is not “necessary” and is operationally not required (anymore). This means that the blockage of FL 300 as flight-plannable level over the NAT-region is best to be deleted as IFATCA policy-statement.

3.2. This particular policy statement is not anymore of actuality and so it can be proposed for deletion.

Recommendations

4.1 It is recommended that the following IFATCA-Policy statement is deleted:

Within the NAT region where RVSM is in operation, FL 300 would be established as a nonflight plannable level as part of the “in-flight emergency contingency” procedures as they apply to the Organised Track System.

Last Update: January 19, 2020  

December 22, 2019   61   Jean-Francois Lepage    2015    

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