Long ago, in Shadis magazine there was an article by someone, probably Monty Cook, who had once worked at ICE. They sat down to play Spacemaster, spent two hours making characters, and died within the first five minutes due to a critically failed piloting roll. To which the GM said, tough luck roll up new characters.
My own thought is that in fluff terms it depends a great deal on whether the inertial dampers are working and whether the ship has any thrust or anti-grav functioning. If nothing's working, you're probably dead. The good news is that space is mostly empty so you're only likely to crash when you're close to something big. Inertial dampers can take off around three Gs they're the main reason there are maneuver drive TL limits if Fire Fusion and Steel is to be believed.
In game terms I'd work from that, does the Engineer have time to route temporary power from the laser turrets to the maneuver drive or intertial dampers, or can they vent some atmosphere to make a tiny angular deflection? Can the pilot use control surfaces to decelerate through atmosphere before impact? How much drag does opening the cargo bay get you? Lots of fun and tense skill rolls to be made.
In the end though, it comes down to how well will your players take a seemingly arbitrary TPK. Generally speaking, I find players get tired of sf really fast if they just die instantly from things beyond their control. On the one hand you don't want them to feel powerless, as realistic as that can be, but on the other hand you don't want them to think they have plot immunity. For Traveller, I'd suggest 1d - 5d damage to characters in a crash, depending on the circumstances.