Amendment to UK Regulation (EU)139/2014

We asked for comments on our proposal to make changes to Acceptable Means of Compliance (AMC), Guidance Material (GM), Certification Specifications (CS) and Guidance material (GM) for UK Reg (EU) No 139/2014 regarding the ICAO change to the reporting method of pavement bearing strength from Aircraft Classification Number (ACN) and Pavement Classification Number (PCN) to Aircraft Classification Rating (ACR) and Pavement Classification Rating (PCR).

The consultation for the amendments to Regulation UK (EU) 139/2014 that will also be included in CAP168 closed on the 25 October 2024, there were eight responses. 

Many of the responses  were in the form of questions which are addressed in the responses below. Generally, the proposed changes were accepted.

One key concern was the need for the extension of the PCR applicability date. Following the consultation comments the CAA took quick action to promulgate the PCR extension for both using aircraft and technical evaluations via SkyWise, therefore giving airports more time to plan and finance the required pavement evaluations to become compliant.

Consultation timing 
A comment was made relating to the timing of the consultation being too close to the applicability date.  The CAA recognise the PCR change timing is not ideal and was a result of several factors outside of its control which led to delays not least COVID lockdown and the recent general election both of which slowed down and paused regulatory development. This is a reason that an extension to the applicability date will be announced.

Airport category and complexities 
Comments were received regarding the use of PCR data at different category aerodromes  i.e. non- complex / complex aerodromes with a suggestion that the matrix is only applied to commercial aerodromes, however PCR applies to all licensed and certificated aerodromes with a hard runway operating aircraft over 5, 700kgs, there is no differentiation to the category or complexity of the aerodrome.

Extension to the PCR applicability date
There were several comments relating to the extension of the PCR applicability date. Four of the eight responders requested an extension to the applicable date.  

The CAA had already indicated that applicability date was going to be extended and would be notified after the consultation closed. The extension periods for both U and T compliance will be advised shortly and will likely exceed the suggested time frames suggested by responders providing adequate time to undertake the required evaluations.  
 
Capital costs 
One airport raised the capitol costs of the conversion to PCR T.  The CAA is aware of the costs and planning required to undertake a full technical survey in to meet the requirements for the technical declaration. This is the prime reason that an extension to the applicability date which will be announced, allowing aerodromes to plan for the required testing which also provides the option to spread the cost of the testing program over an extended period. The extension of the PCR applicability is in line with other  states which are also extending applicability deadlines. 

Lack of guidance for U evaluation
Lack  guidance  was mentioned particularly relating to the U method. The use of using aircraft and the ICAO software to perform a calculation for the heaviest aircraft was identified and promulgated as soon as possible once evaluation and training had been undertaken and methods verified at the ICAO Airport Pavement Expert Group by the CAA. 

The CAA provided a webinar on the use of the software packages for PCR calculation and also offered ongoing support on a one-to-one basis for airports with software demonstrations and guidance together with assistance with calculating U values. ICAO Doc 9157 Aerodrome Design Manual Chapter 3 is also a source of guidance CAP168 already contains guidance on PCR calculations which is suitable for both certificated and licensed aerodromes which was promulgated by SkyWise. 

Use of U evaluation until next pavement maintenance 
There were several comments made to the use of U until the next planned maintenance.  The use U is acceptable as long as plans are made to undertake the required technical assessment by the applicability extension deadline date.   Planned maintenance or rehabilitation is the ideal time to undertake technical evaluation depending on how the maintenance plan falls within the revised applicability dates.

ACN/PCN data can still be used until the T evaluation is completed by the deadline, the information will remain in the AIP until the PCR values are notified to AIS. An extension to the revised applicability will be notified, any further request to extend beyond the revised applicability date will be subject to discussion with the allocated aerodrome inspector.

Pressure plate testing may not provide adequate information for the pavement technical evaluation given the subbase requires evaluation via cores, DCP, and GPR surveys.

Training courses 
Regarding training a comment was made relating to training, ICAO training courses are available, the training available is overview and technical for engineers. 

Software suitability
There were comments regarding the suitability of the software packages currently available for PCR calculations.  The software packages do provide output data to perform the PCR calculation for T evaluations including CDF values and life expectancy based on design. Other states are developing software not least the UK which will become available in the near future. 

EMAS 
EMAS and use of existing arrestor beds consideration was highlighted, a question was raised regarding consideration for existing EMAS which are not identified in the proposed CS and if installed to what extent of the RESA can be substituted.  

The intent is to introduce a CS and standard to be met for new EMAS installations. The substitution of RESA is subject to safety assessment and EMAS design intent considering the operations at the aerodrome.  RESA reduction will only be considered for new EMAS installations given EMAS is an engineered solution and is very different from a soft arrester bed.  If current soft beds are employed these remain acceptable in their current form, however,  additional RESA reduction in this application will not be considered.  

There were no negative responses for the inclusion of the CS in 139/2014 and CAP168. 

AGLCS system design 
Comments were received relating to the change to the design of AGLCS and its required financial investment. Comment also referred to the text update to CS ADR-DSN.S.890 requesting if there is an expectation that existing approved AGLCS systems will need safety cases re-evaluated to meet additional requirements where they may present over the existing, or will this apply for new/amended installations?

Adjustments can be  undertaken when a change is made to a system  or its updated or replaced and in consultation with the aerodromes allocated ATM inspectors.

GRF 
There were no comments relating to the proposed amendments to GRF.However, this element will be removed from this task and added at a future date, this is due to the potential of further changes by ICAO prior to issue of the State letter which is now estimated as 2027. 

CS ADR-DSN.D.335
Comment received relating to the revision of CS ADR-DSN.D.335 being the inner transitional is less ‘demanding’ at 1:3 vs 1:7, it’s still tight for larger aircraft tails, concern was raised as this contradicts some of the taxiway separation and holding position distance tables which no longer fully protect against larger aircraft tails as mobile obstacles. 

The introduction of new OLS surfaces will help with the operational assessment and establishment will address these points. The new OLS surfaces will become applicable in 2030.  The required work to update AMC / GM and CAP168 will commence in 2025 with the aim for adoption well in advance of the applicability date, therefore mitigating the problem, any penetrations will always be subject to an aeronautical study.

AMC1 ADR.OPS.B.090
A comment was received relating to operation of higher code aircraft and impacts to existing permissions. 

If higher code aircraft when factored into the aircraft mix do not exceed CDF 1 the pavement life should be calculated  by the PCR software for the current and forecasted aircraft mix at the aerodrome. 

Overlays prior to the end of forecasted design life will alter the PCR and CDF at which point they should be recalculated. Should the traffic mix alter the PCR and CDF calculations the process should be repeated by using the PCR software.  

Current permissions are unlikely to be affected but the effect of pavement should be assessed if the higher code aircraft when evaluated in the aircraft mix causes the CDF to exceed CDF1 which is then an overload operation. 

Continuous overloading of the pavement will affect the overall pavement life, its planned maintenance and lead to early failure.  It is the responsibility of the aerodrome to effectively manage this element within the scope of the overload requirements and aerodrome pavement inspection and maintenance procedures. 

Following the consultation comments the CAA took quick action to promulgate the PCR extension for both using aircraft and technical evaluations via SkyWise, therefore giving airports more time to plan and finance the required pavement evaluations to become compliant.

The CAA does not envisage additional rule making  activity regarding the implementation of the change areas outlined in the consultation, the update will consist of AMC/ GM amending or adding to existing provisions.