IMPORTANT POINT
It would be difficult to have a re-appreciation of evidence and facts by Supreme Court when two specialist authorities/tribunals having applied their mind to it.

JUDGMENT :

SANJAY KISHAN KAUL, J.

1. We thought that our judgment in Delhi International Airport Limited vs. Airport Economic Regulatory Authority of India, 2022 SCC Online SC 850 would have resolved all the issues. It appears not.

2. Applications have been filed by both Delhi International Airport Limited (DIAL) and Mumbai International Airport Limited (MIAL) predicated on the discovery of what is stated to be a ‘new and important piece of evidence’ which was not within the knowledge of the applicants even after exercising due diligence. The applicants have referred to a letter dated 24.05.2011, which is an internal correspondence between the Ministry of Civil Aviation (for short ‘MoCA’) and the Airport Economic Regulatory Authority (for short ‘AERA’) inter-alia stating that “Accordingly, in this case the proposed approach is to back solve the initial aeronautical Asset Base given the aeronautical charges. In the State Support Agreement, in Schedule-I the method for calculating Asset Base for the first regulatory period has been defined.”

3. The aforesaid is stated to have given rise to an error apparent on the face of the record in Paras 50 and 63 of the judgment.

4. If we turn to our judgment under the heading “Calculation of Hypothetical Regulatory Asset Base (HRAB)” we have proceeded on the basis that the two airports in question were not set up de novo but instead, existing airports were taken over. Consequently, assets as reflected in the books of accounts would record depreciation. This had created difficulty in arriving at a value of the Regulatory Base for the first year of the first control period. Apart from this, there was a common book of assets for several airports across India. Thus, the State Support Agreement (for short ‘SSA’) provided for HRAB to be derived by working backwards, which would have a cascading effect for successive years and was thus crucial. In the formula in question this would imply that the term ‘RB’ as defined, thus, base calculation for RB0 would have an impact on the calculation of RB1 and for further years. HRAB was to determine RB0.

5. In Para 50 of the judgment, the controversy in relation to HRAB was set out. This Court gave its imprimatur in Para 63 to the view adopted by AERA and TDSAT.

6. The submission on behalf of the applicants is that MoCA’s letter dated 24.5.2011 relates back to the core issue of calculation of HRAB by the method of back solving. We have already recognized the cascading effect as stated aforesaid. The question was whether in terms of the SSA dated 24.06.2006, the HRAB has been correctly calculated.

7. In effect, it has been submitted that this Court confined its finding to the expression “pertaining to aeronautical services” but the aspect of ‘single till’ had not been dealt with and that HRAB should be computed on the basis of ‘single till’ mechanism. It is conceded that this aspect was not dealt with by the TDSAT either. Suffice to say that this Court proceeded on the basis of the opinion of the TDSAT and did not expand beyond the ambit of what the TDSAT had opined on.

8. In substance, the contention on behalf of the applicants is that the ‘single till’ mechanism was prevalent in the year 2008-09 where there was no distinction between aeronautical and non-aeronautical revenue and the entire revenue, i.e. aeronautical and non-aeronautical were considered as composite revenue and tariff was fixed on a cost-plus basis. Thus, for determining the opening of HRAB for FY 2009-10, the entire revenue of the previous year, i.e. 2008-09 ought to have been considered.

9. A reference has also been made to a letter dated 18.06.2018 of the Airports Authority of India, which stated that “the airport charges were fixed on cost recovery principle….but allowing for all aeronautical revenue plus contribution from non-aeronautical revenues accruing from the operations of the airports to its operations.” This has to be read in the context of the provisions of Schedule 1 of the SSA, and th