Rostrum Leasing 1 DAC v MAE Aircraft Management WLL [2026] EWHC 57 (Comm)
Rostrum Leasing 1 DAC, an Irish aircraft lessor, leased a Boeing 737-300PCF cargo aircraft to MAE Aircraft Management WLL, a Bahraini cargo operator, under an agreement executed in May 2021. The lease required MAE to pay basic rent of US$160,000 monthly, with the obligation described as “absolute and unconditional” and expressly excluding any right of set-off. Crucially, the lease contained detailed provisions for inspection and acceptance. MAE was required to conduct a technical inspection and sign a Technical Acceptance Certificate (TAC), which would constitute “conclusive proof” that the aircraft was satisfactory and that MAE had unconditionally accepted it.
MAE paid some rent initially but had stopped by 2022. In July 2024, Rostrum served notice of termination of the lease (which would have expired at around the same time in any event) and claimed arrears of rent. It commenced proceedings in December 2024 and applied for summary judgment in May 2025. MAE mounted a spirited defence: the aircraft, it claimed, had never been properly “delivered” under the lease because it arrived riddled with defects rendering it unairworthy (despite the aircraft having a valid certificate of airworthiness). The TAC, MAE argued, should not bind it because it was signed before the lease was executed and contained reservations about outstanding defects. The consequence of this (MAE said) was that the obligation to pay rent had never arisen. It also made an extensive range of counterclaims, including for damages arising out of Rostrum’s presentation of a winding-up petition against it in Bahrain. Rostrum applied for summary judgment on the rent claim and the counterclaim.
Philip Marshall KC, sitting as a Deputy High Court Judge, granted summary judgment for rent accrued up to the termination notice of July 2024. The judge found MAE was estopped by convention from denying that delivery had occurred and rent was due. The doctrine of estoppel by convention applies where parties have conducted their affairs on a shared assumption – here, that the aircraft had been delivered and rent was payable – and it would be unconscionable to permit one party to resile from that assumption. The evidence in this case of such a common assumption was clear: MAE had paid rent for months while it was (on its case) fully aware of the alleged defects, its executives had requested payment schedules, and as late as October 2024 it had acknowledged owing US$5.3 million. So was the prejudice to Rostrum: had MAE not acted on this basis, Rostrum would have exercised its right to terminate the lease and retake possession of the aircraft. He accepted, however, that MAE had an arguable case that Rostrum could only claim damages in respect of the period after termination of the lease, subject to questions of mitigation and the penalty rule, and that these questions should go to trial. The judge, applying Olympic Airlines v ACG Acquisition XX LLC [2013] EWCA Civ 369, also found that MAE were estopped by contract from asserting that the aircraft had any defects beyond those expressly set out in the TAC. Given this, MAE’s counterclaims for damages arising from alleged defects not stated in the TAC had no real prospect of success.
To read the full judgment please click here.
James Kane led by Thomas Munby KC, instructed by Bree Taylor and Reece Davison of Alius Law.
