I found this very interesting article online by Topher Kessler
Apple’s latest MacBook Air systems offer attractive improvements over prior models, but some of the systems appear to be suffering from a bug that results in intermittent loss of video output. When using an affected system, the screen may randomly blink to black for a brief second, or go to sleep and require a button be pressed for the system to wake again.
There is no indication on how widespread this bug is, but a number of affected users have noted the problem in a lengthy and growing Apple support discussion thread.
When the screen flashes intermittently, the system does not appear to shut down or sleep, since audio and other activity may continue; however, this does not occur at the times where the systems do go to sleep. This bug appears to affect both the 11-inch and 13-inch models, though the problem seems to happen more with the 13-inch MacBook Air. Additionally, it appears to happen more when on battery power than when plugged into its AC adapter; however, some have reported it happening on AC power as well.
The random nature of the problem suggests it is likely not software-based, so it may revolve around a physical sensor such as a magnetic switch in the lid or chassis, that could be contributing to the problem. Recently, a YouTube video of the issue surfaced, showing an extreme condition of the bug, and its apparent tie to physical movement of the systems:
If you are experiencing this problem with your MacBook Air, then you can try some hardware resets to see if they can help the situation. The first is to perform a PRAM reset, by rebooting the system and immediately holding the Option-Command-P-R keys all at once. Continue to hold them until the system automatically resets and sounds the boot chimes again, and then release the keys to allow the system to boot normally.
The next reset you can do is for the system management controller (SMC), which governs how power and sensors are handled in the system. To reset this controller on the MacBook Air, first shut down the system and plug it into the AC adapter. Then press and hold the Shift-Control-Option keys on the left-hand side of the keyboard, followed by depressing the power button. Release all keys at the same time, and then press the power button to start the computer again.
If these reset routines do not fix the issue, then the next step would be to contact Apple and have the system replaced or serviced, especially since at this time the systems should still be under warranty. Since this issue came to light, Apple has swapped out a number of these for affected customers, likely with the intent of investigating the problem.
Depending on what Apple’s engineers find, we may see a firmware or software update to address the problem in the near future. Apple recently issued a software update for the Mid 2013 MacBook Air; however, this was to address a flickering display problem specific with use of Adobe software, and does not appear to address the issue at hand. Meanwhile, even though the issue may still happen, consider using the systems with the AC adapter attached, to at least reduce its prevalence.
This issue follows a similar, though unrelated, bug seen in the Mid-2010 MacBook Pro, where a faulty series of graphics cards has plagued those systems with regular crashes and black screens. In that case, Apple addressed the issue with a software update, though subsequent OS updates and upgrades have brought the issue back or exacerbated it for some systems.