United flight 1816 from Dallas-Fort Worth to San Francisco landed safely Thursday morning after it “encountered a hydraulic leak as it neared its destination,” airline officials said.

The flight was the latest United aircraft to encounter mechanical issues in flight in a series of recent problems for travelers on the airline.

A United spokesperson confirmed that the flight experienced a hydraulic leak as it approached the San Francisco International Airport. The aircraft — an Airbus A320 — had 150 passengers and five crewmembers on board, according to the airline.

Flight 1816 landed safely after its nearly four-hour trip from Texas and all passengers were able to deplane normally at the gate.

However, the United statement noted that emergency vehicles were standing by as a precaution during the landing after smoke was seen around the landing gear. The released statement said smoke is commonly visible in such instances when hydraulic fluid comes in contact with brakes.

Earlier this week on Monday, another United flight bound for San Francisco from Australia had a “maintenance issue” and was forced to return to Sydney, airline officials said.

In that case, the airline rebooked the passengers on a later flight to San Francisco after providing overnight accommodations.  

YouTube account New York Aviation posted video of the plane’s take off and return landing at the airport in Sydney. 

The recent rash of incidents on United flights stretch back to early last week, with multiple United aircrafts facing problems that forced flights to return to their point of departure or make emergency landings.

On March 4, United flight 1118 bound for Fort Myers, Florida, had to return to George Bush Intercontinental Airport after the engine caught fire minutes after takeoff. Airline officials later said an investigation determined that bubble wrap had been sucked into the engine’s air intake.   

On Thursday and Friday last week, two flights left SFO and were diverted to LAX. On Thursday, a jet lost a wheel during takeoff. The wheel crushed one car and damaged several others in an SFO employee parking lot. 

The following day, a plane that was bound for Mexico City was forced to land after it experienced a problem with its hydraulics system.

Also on Friday morning, United Flight 2477 from Memphis to George Bush Intercontinental Airport in Houston veered off the runway just after landing. 160 passengers and six crew members on the flight were forced to depart the plane using air stars on the open runway. There were no injuries in any of these recent incidents.

United has maintained that the recent series of safety incidents were unrelated, with aviation experts backing up the airline’s statement.