Germany's BDL aviation federation announced late Thursday that airlines such as Lufthansa and Air Berlin intended to immediately enact the two-person rule in consultation with the Federal Office of Civil Aviation.
A French prosecutor said Thursday that the recovered voice recorder indicated that the Germanwings' co-pilot kept the chief pilot locked out of the cockpit and deliberately let the plane crash into a French alpine range.
All 150 people on board, including 75 Germans, 50 Spaniards and nationals of 14 other nations, were killed on the flight from Barcelona to Düsseldorf. Victims' families visited the crash site on Thursday.
BDL chief executive Matthias von Randow said in the future no pilot would be allowed to remain alone in a cockpit during a flight.
Two other German airlines, Condor and TuiFly, had also agreed to adopt the rule-change, he told the German news agency DPA.
The move was welcomed by German parliamentarian and government transport spokesman Arnold Vaatz, who said it would be a "confidence-building signal."
The German pilots' trade union urged caution. Its president, Ilja Schulz, said it was also important to examine "which disadvantages" could result from changing procedures.
Several other European airlines, including EasyJet and Norwegian Air Shuttle said they too would require two crew members to be in a cockpit at all times. Several other European airlines, such as Finnair and Czech operator CSA already do so.
The Frankfurter Allgemeine Zeitung (FAZ) newspaper on Friday quoted a veteran cabin crew member of American Airlines as saying that if one pilot needed a toilet break, another crew member joined the remaining pilot in the locked cockpit.
The remaining pilot donned an oxygen mask before the other pilot left in case of a sudden loss of cabin pressure.
FAZ also quoted a Jetblue cabin personnel member: "For me it is usual to spend 10 to 15 minutes in the seat of the pilot or co-pilot and to wait until he returns."
In his shock assessment of flight 9525's final minutes, Marseille prosecutor Brice Robin on Thursday said the co-pilot Andreas Lubitz "intentionally" put the Airbus A320 into descent before it hit the Les Trois Eveches mountain range, 100 kilometers (60 miles) north of Nice.
There were reports in the mass-market Bild newspaper as well as other media stating that Lubitz suffered from depression six years ago during his training. Lufthansa officials said Lubitz passed all health and psychological tests before he was put in the cockpit.
Carsten Spohr, the chief executive of Lufthansa, Germanwings' parent company, said the German airline had "no knowledge on what might have motivated the co-pilot to take this terrible action."
Lufthansa chose its staff "very, very carefully," Spohr added.
Lubitz had joined Germanwings in September 2013, directly after training, and had flown 630 hours.
"He was 100 percent aviation worthy, without any conspicuous anomalies," Spohr said.
Chancellor Angela Merkel said the tragedy had taken on an "incomprehensible dimension" that went beyond "anything we can imagine."
Late on Thursday, police investigators began searches of the 27-year-old co-pilot's apartments in Düsseldorf and in his home town of Montabaur.
In its Friday edition, Germany's tabloid Bild newspaper quoted security sources as saying the locked-out pilot had used an emergency axe to try to open the reinforced cockpit door.
It claimed that Lubitz also had a pause earlier in his career for medical treatment. FAZ said the break occurred six years ago during his training to become a pilot.
ipj/bk (AFP, dpa, Reuters, AP)