An Air India ‍Boeing 777 aircraft had to turn back after a drop in oil pressure forced the pilots to turn off one of the jet’s engines, India’s aviation regulator said on Monday.

Axar.az informs, citing Reuters, the aircraft, which was headed to India’s financial ⁠capital of Mumbai, landed safely back in Delhi and the incident will be investigated, the Directorate General of Civil Aviation (DGCA) said in a statement. Modern aircraft are designed to safely fly and land on a single engine, if required.

On ⁠Monday, pilots observed a low engine oil pressure on the B777-300ER aircraft’s right-hand engine during ‌flaps retraction after take-off. The pressure shortly thereafter dropped to zero and the crew shut down the engine and turned back as per procedure, the DGCA said.

The aircraft is 15 years old and has flown to locations such as Vienna, Vancouver and Chicago, according to Flightradar24.