THE PROPELLER which fell off a Regional Express (Rex) flight as it was approaching Sydney has been found in bushland southwest of the city.

A police helicopter on patrol spotted the Saab 340 propeller in bushland off The River Road at Revesby about midday on Tuesday.

The plane, which was travelling from Albury to Sydney on Friday, was forced to make an emergency landing after one of the aircraft’s propellers fell and plunged to the ground over the city’s suburbs. No one on board was harmed although passengers were said to be shaken.

“Rex has decided, by abundance of caution, to immediately remove from service and quarantine all propeller gear boxes and shafts of the same series as that of the incident for further inspection and testing if warranted,” Rex said in a statement on Monday

Grahame Hutchison, an aviation photographer, snapped pictures of the stricken plane at Sydney Airport as it was towed from the terminal after its passengers disembarked.

He told news.com.au the pilots should be commended for staying calm under pressure.

“I would imagine for the passengers it would be a fairly frightening experience so hats off to pilots, they’ve done a great job.”

He said it was rare to see such damage.

“That’s the first time I’ve seen an aircraft with one propeller.

“It’s just luck the propeller didn’t come off and hit the wing or the cabin and that would have been tragic. It could have gone straight into fuselage,” he said.

On Friday, a Rex spokesman said, “The crew followed standard operating procedures and the aircraft landed normally and on-time at Sydney Airport.”

Regional Express is Australia’s largest independent regional airline and operates a fleet of more than 50 Saab 340 aircraft on 1500 weekly flights to 58 destinations throughout the country.

BREAKING NEWS: Rex Flight ZL768 VH-NRX from Albury to Sydney lost a propellor in flight and then made a safe landing @SydneyAirport #avgeek pic.twitter.com/uEMUI8lKF6 — 16Right Media (@www16Right) March 17, 2017

The pilots reportedly acted calmly when the propeller dropped off sending a matter of fact message to air traffic controllers in Sydney.

“The prop has just fallen off the aircraft and standby for further instructions,” a pilot said, according to ABC News.

“REX 768 ... our propeller has just sheared off,” the flight deck continues.

“We’ve got normal controls, still be able to fly would require 1-6 right and we should be able to conduct a precautionary landing.”

The propellers provide thrust to the aircraft and rotate at hundreds of times per minute. Propellers are generally used only on smaller aircraft with larger Boeing and Airbus planes using jet engines.

Flight ZL768, which was approaching Kingsford Smith Airport from the north according to data from website Flightaware, landed safely at Sydney about midday. There are no reports of any injuries among the 16 passengers and three crew.

In the pan-pan call, the crew said the propeller assembly had “dislodged”, Civil Aviation Safety Authority spokesman Peter Gibson told AAP, while photographs of the plane on the ground showed the right propeller missing altogether. Mr Gibson said during his 20 years in the aviation industry he’d never heard of a propeller falling off a plane.

“I’ve never come across it ... it’s very unusual,” he said.

A “pan-pan” is one step away from a full mayday distress call.

The propeller detached about 19kms from Sydney airport which could mean any debris is located somewhere close to Gordon and Pymble in Sydney’s north shore or the Ku-ring-gai Chase national park. However, there are some reports it could have occurred earlier in the flight, placing debris over the city’s south west.

The ATSB is deploying a team of three investigators with expertise in materials failure engineering, recorded flight data analysis, and human factors.

In a statement, the ATSB said, “Over the next few days, investigators will examine the aircraft, interview the flight and cabin crew, collect maintenance records and recorded flight data.

“The ATSB urges anyone who finds a piece of suspected aircraft debris NOT to handle it.”

Rather, people should call local police or the ATSB on 1800 020 616.

If anyone in SYD's southwest has a new lawn ornament today, call Regional Express. They're kinda looking for their missing propeller #whoops — TheFlightlessMallard (@thequacklife) March 17, 2017

In a statement, the airline said, “Regional Express (Rex) flight ZL768 operating from Albury to Sydney on 17 March 2017experienced an event associated with the aircraft’s right propeller assembly.

“The crew followed standard operating procedures and the aircraft landed normally and on-time at Sydney Airport.

“The 16 passengers and 3 crew members were met by Rex staff upon arrival and did not require any further assistance.

“Rex is investigating the cause of the incident, and the matter has been reported to the ATSB as well as the Civil Aviation Safety Authority CASA.”

benedict.brook@news.com.au