When a Southwest Airlines flight attendant entered the cockpit during a flight and saw an iPad showing what appeared to be live footage from the plane’s lavatory, one of the pilots assured her it was a “top secret security measure,” according to court documents. Now, the airline denies there was ever a camera at all.

The flight attendant, Renee Steinaker, sued Southwest Airlines last year for emotional distress, negligence, invasion of privacy and sexual harassment. But on Saturday, the airline said it would “vigorously defend the lawsuit,” claiming that it had investigated the allegations at the time of the alleged incident, in February 2017, and had found no hidden camera.

“We can confirm from our investigation that there was never a camera in the lavatory,” Southwest Airlines said in a statement. “The incident was an inappropriate attempt at humour, which the company did not condone.”

Ms Steinaker, who has worked as a Southwest flight attendant for decades, filed the lawsuit in 2018 in Maricopa County, Arizona, before the case was moved to US District Court in August, according to her lawyers.

One of the lawyers, Ronald Goldman, who has practised aviation law for nearly 50 years, said he had never seen a case like this.

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“The audacity of what happened is stunning,” Mr Goldman said in an interview on Saturday. “This kind of conduct is so beyond the pale, in my opinion, that it jeopardised the safety of the flight and created a hostile work environment for the cabin crew.”

Lawyers for the pilot, captain Terry Graham, and his co-pilot, Ryan Russell, did not respond to requests for comment.

Ms Steinaker was one of four flight attendants working on Southwest Airlines Flight 1088, which departed Pittsburgh for Phoenix on 27 February, 2017. The plane, a Boeing 737-800, had lavatories in the front and back for the passengers and crew, according to court documents.

According to the complaint, about two-and-a-half hours into the flight, Mr Graham asked for a flight attendant to come to the cockpit as he went to the lavatory. Southwest protocol requires that two crew members be in the cockpit at all times.

Ms Steinaker entered the cockpit, noticed an iPad mounted to the windshield next to the captain’s seat and saw what appeared to be a live-streaming video of Mr Graham in the lavatory, according to the complaint.

When questioned, Ms Steinaker said, Mr Russell admitted the video was from a functioning live-stream camera installed in the lavatory. He told Ms Steinaker cameras were a top-secret security measure that had been installed in the lavatories in all the airline’s 737-800 planes, the lawsuit alleges.

Mr Russell then instructed Ms Steinaker not to tell anyone about the camera, which he said was hidden so no one could find it. Ms Steinaker then used her phone to take a picture of the iPad, which showed Mr Graham in the lavatory at the time, according to the complaint.

When the captain came back to the cockpit, Mr Russell left to use the lavatory. Finding herself alone with Mr Graham, Ms Steinaker confronted him about the cameras, but he refused to respond and blocked her view of the iPad, the lawsuit alleges.

Ms Steinaker told the other flight attendants what had happened and showed them the picture she had taken of the iPad. When the plane landed in Phoenix, the two pilots immediately disembarked, in violation of airline protocol, according to the complaint.

In his quick departure, Mr Graham, a federal flight deck officer, left a loaded firearm unattended in the cockpit, the lawsuit alleges, in violation of Federal Aviation Administration regulations.

Upon landing, Ms Steinaker and other crew members filed a written incident report to Southwest and requested that the airline seize the iPad and save the cockpit voice recording. It is unclear whether the airline complied, Mr Goldman said.

According to the complaint, the airline told Ms Steinaker it would investigate the incident and a supervisor warned her: “If this got out, if this went public, no one — I mean no one — would ever fly our airline again."

Mr Graham and Mr Russell later departed Phoenix for Nashville on time with a new crew of flight attendants. To Mr Goldman’s knowledge, both are still employed as pilots.

“Only a pervert would think this is funny,” Mr Goldman said. “A cockpit is not a playground for peeping Toms.”

Since the incident two years ago, Ms Steinaker and her husband David Steinaker, a fellow Southwest flight attendant, have faced retaliation from the airline, Mr Goldman said. Both have worked as flight attendants for decades with “exemplary” track records, but now they are repeatedly checked at the gate, interrogated and drug tested, he added.

Mr Goldman said the episode was outrageous and scarred Ms Steinaker, causing her considerable emotional distress.

“This was not just a passing event,” he said. “This was something that violated her workplace, her sense of safety and security, and really caused her to have a fear that she could be paired with people like this again, and the airline wouldn’t care.”