Instant Expert

With Ed Bellamy


How Sherburn's success could lead to more Instrument Approaches in the UK

It was a long and winding road for Sherburn-in-Elmet to gain its Instrument Approach this year but it may have eased the way for others

In June this year Sherburn-in-Elmet made history by becoming the first UK aerodrome with an Air/Ground Communication Service (AGCS) to publish an instrument approach procedure (IAP). The neighbouring Leeds East Airport (former RAF Church Fenton) followed suit in August.

IAPs in the UK, particularly those of the Global Navigation Satellite Systems (GNSS) variety, have sometimes been a vexed subject. It would take several times my normal column length to tell the full story of how it took one of Yorkshire’s preeminent GA destinations the best part of eight years to achieve implementation, but suffice to say, persistence finally paid off.

It is a complex and expensive process for aerodromes to establish instrument approaches, and as a result it tends to be the preserve of those serving commercial air transport. There is also a UK requirement for IAPs to be provided with an approach control service, and prior to 2014, dispensation from this was only granted to specific operators – known as ‘discrete’ procedures. 

Navigating the process

In 2014 the CAA published a policy on alternatives to the approach control requirement, in the form of CAP 1122. Several aerodromes showed interest, but most fell by the wayside. Some persisted and Sherburn and Leeds East join a small number of GA aerodromes, such as Kemble and Sywell, who have completed the process. The procedures are all Required Navigation Performance (RNP) and based on GNSS.

A new IAP is still considered an ‘airspace change’, even when established outside controlled airspace. The requirements of the Airspace Change Process (ACP) under CAP 1616 therefore apply. Stapleford, Haverfordwest, Cumbernauld and Lee-on-Solent have also made applications and will hopefully receive approval next year.

A recurring issue for the Sherburn team was that much of the policy detail was being tested for the first time. Everything from weather reporting to obstacle surveys had to be considered in the context of an aerodrome smaller than the norm. Aside from the subject of air traffic control, a published IAP comes with extensive safety and compliance requirements.

The surrounding airspace environment also proved to be complex, for example co-operation procedures had to be established for nearby controlled airspace and various glider sites. The Leeds East and Sherburn profiles were modified several times after engagement with local airspace stakeholders.

Sherburn airfield

Flying the approach

The IAPs come with some restrictions that may be unfamiliar to those with experience flying IFR in states such as the USA, France or Germany. A key difference is that the UK does not provide regionalised approach control, hence the use of Prior Permission Required (PPR) to avoid multiple aircraft arriving at the same time. In the case of Sherburn, the trajectory of the procedures also overlaps with Leeds East, due to the orientation of the runways.

Pilot briefing documents are published for each aerodrome, covering the different stages of booking PPR and then flying the approach. For Sherburn, the procedure is only intended for use when the weather requires it. IFR arrivals in VMC should follow normal visual joining procedures. Training under VFR is permitted with prior agreement and a safety pilot or instructor onboard.

While there is no approach control service, Leeds Bradford or Humberside airports will provide arriving aircraft with UK Flight Information Services outside controlled airspace, subject to capacity. When approaching Sherburn from the west, it may be possible to obtain a clearance through the Leeds Bradford CTA. The airspace over the Vale of York can be quite busy and there is extensive glider activity, so IFR inbounds must keep a good lookout when in VMC.

Once on frequency with Sherburn or Leeds East, aircraft must announce their position at various points on the procedure, but otherwise the normal rules for ACGS aerodromes apply – i.e. the pilot in command is responsible for managing interactions with other aircraft.

Feedback from Sherburn suggests that the descent profile from some directions needs anticipation and a prompt descent. The legs between the approach fixes are short, so consider configuring earlier than normal. The final approach angle is 3.5°. When conducting training in VMC, be aware that it is possible for the visual circuit to be on a different runway. The Sherburn IAPs are to RW10/28, but there are also the grass runways 06/24 and 01/19. Approach traffic must integrate with the visual circuit as required.

For more information read the pilot briefing documents, available on the respective aerodrome websites for Sherburn and Leeds East.

Now that winter is approaching, the ability to fly an IAP is becoming more significant. GA aerodromes are traditionally quiet places when the weather is bad, but for potential visitors to Sherburn or Leeds, the £100 hamburger will now be on the menu most days of the year.

Sherburn Instrument Approach

Lessons learned

When the CAP 1122 policy (now replaced by CAP 2304 was first published in 2014, it was expected to be applied in quiet locations with low complexity airspace. The possible flaw with this assumption was that with a few exceptions, such as the Highlands and Islands airports, the aerodromes for which an IAP would make business sense tend to have higher levels of traffic and complexity in the surrounding airspace.

Applicants found that more engagement was required with local airspace stakeholders than originally anticipated – for example, nearby ATC units, other aerodromes or glider sites. The implications of having an IAP nearby were not always fully understood by stakeholders, but this will improve as operational experience is gained. Noise or other environmental concerns have not been a significant issue so far, but applicants must still provide some evidence of impact.

The limitations applied for utilisation of uncontrolled IAPs (e.g. 10 approaches per day) have come in for criticism, but in practice demand for more than one or two approaches per day has not materialised. As the number of IAPs hopefully increases, we may see more demand as pilots start flying from one IFR equipped aerodrome to another. IFR training is also a benefit that has not yet been fully exploited.

Sherburn airfield

Easier for other GA aerodromes

Hopefully the success of Sherburn and Leeds East will ease the path for other GA aerodromes applying for IAPs. The process will always be quite expensive and time consuming, but I believe it will become less iterative. More of a ‘template’ way to do it will emerge, even though some local requirements may vary. Currently there is some inconsistency in the limitations and procedures between different IAPs – aerodromes and the CAA should more actively minimise this in the future. Funding has previously been available for aerodromes through the joint CAA and Department for Transport GNSS rollout scheme. The scheme is now closed for new applications but may reopen in the future.

The lack of regionalised approach control in the UK does leave a recurring issue (real or imagined) around airborne conflict. This may limit the number of RNP IAPs to GA aerodromes, since it places a burden on aerodromes to implement alternative procedures, such as PPR, and makes the use of the IAPs less flexible.

There may be a solution in the context of the Airspace Modernisation Strategy (AMS). The proposals in the recent AMS consultation suggest that national Flight Information Services with surveillance may be on the table, which in theory could also provide a deconfliction service or approach control to aerodromes outside controlled airspace.


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