Thanks to cockpit data recorders, investigators know the precise time Andreas Lubitz sent Germanwings Flight 9525 into a mountainside and the maneuvers he used to do so. But when it comes to evaluating Lubitz's psychology as the plane crashed, investigators have had little more to work from than a cockpit voice recording that, according to French prosecutors, revealed he was breathing steadily during the plane's descent. Images that more clearly portray Lubitz's state of mind — and offer more insight into how such tragedies can be prevented in the future — aren't available. That's because cockpit video cameras have never been required by any airline regulator.

Fortunately, that may soon change. According to a recent report in the Wall Street Journal, the International Civil Aviation Commission, the U.N. agency that sets global aviation safety standards, is preparing to make a "big push" for cockpit cameras later this year. (It's unclear whether it will recommend them, or outright require them.) In doing so, it will have the support of the U.S. National Transportation Safety Board, the U.S.'s lead airline accident investigator, which in January listed cockpit cameras among eight safety-related recommendations it made to the U.S. Federal Aviation Administration.

At first glance, the proposal might seem like overkill. U.S. commercial aircraft have been equipped with data recorders since the late 1950s, and were required to install voice recorders in the 1960s. These days, voice recorders are required to log at least the last two hours of a flight's cockpit conversations, while flight data recorders are required to chronicle 88 separate parameters. (In practice, many recorders log more than 1,000 parameters.) In the event of tragedy, those "black boxes" typically provide sufficient information to allow investigators to figure out what happened.

Typically, but not always. One critical factor that airline investigators are keen to review during an investigation is what, precisely, pilots saw during an emergency and subsequent crash. Were the conditions foggy? Was the cockpit filled with smoke? What did various instrument readouts — including navigation displays — tell the pilots? If the instruments are mechanical, they could be frozen with their last reading at the time of impact. But if they're digital, those readings — including weather-related information — are easily lost for good. Consider the 2009 crash of Air France flight 447 from Rio de Janeiro to Paris. The final investigative report on the crash pointedly notes: "We do not know what images of the meteorological situation the crew had on the ND [Navigation Display], which are not recorded." A few paragraphs later, the report adds: "As we do not have the radar image which was provided by his ND, it is difficult to assess the Captain's appraisal."

The investigators eventually concluded that the crash was caused by pilot error related to a temporary instrument failure. But the investigation would have been much easier — and conclusive, especially with regard to the captain's appraisal of weather radar data — if the investigators had access to images of his instrument panel.

Cockpit cameras could also provide information on who was in a cabin, who exactly was controlling a plane at the time of an accident, and even where their hands were in relation to the plane's controls. The U.S. NTSB has specifically cited this kind of data as essential to help unravel cases of alleged pilot suicide. Take, for example, the notorious case of EgyptAir Flight 990, which crashed in the Atlantic Ocean off the coast of New England in 1999. U.S. investigators call it a case of pilot suicide; Egyptian investigators suggest mechanical failure. Cockpit video, in all likelihood, would help to settle the disagreement.

It might offer longer-term safety benefits, as well. Jim Hall, chairman of the NTSB from 1994 to 2001, during which time he led several investigations into pilot suicides, made this point in a March commentary for Time. Referring to crash investigators, he noted: "Without video, they cannot fully understand the actions of the pilots or make safety enhancements to prevent similar events from occurring in the future." Those enhancements could include more finely tuned protocols for profiling the psychological health of pilots.

U.S. law currently requires that cockpit voice recordings only be used for air safety investigations, and forbids their release to airlines, the press, the public, or even courts. (Although leaks have been known to occur.) If cockpit cameras are required, they should be subject to the same restrictions, especially given the certainty they would sometimes record pilot deaths.

That's a macabre thought, and one that has inspired pilots and their unions to oppose cockpit video for years on privacy grounds. The concern is legitimate, but the argument is not. Pilots, as stewards of planes that might contain several hundred passengers, have no more right to privacy in the cockpit than a school bus driver has in the driver's seat while driving down a busy highway. Safety, in both cases, should be the primary concern.