I don't think it's kind you got personal, calling me a looney. The scenario's not real enough to be the dynamic environment we know as flight.
My point was, without any situational awareness of how I magically arrived at your mystical point in time, where I'm suddenly flying an approach and I'm slightly low...
Easy lame answer: Low on glideslope, Go up. Can't go up? Level off and let the glideslope come back in. Don't go down further is probably close enough to the desired result. Can't level off, 'cause you're carrying a metric ton of ice, you're going down if you don't want to stall.
In the real world given only the information you gave, I'd probably go missed and figure out what State I'm in, and over which airport. Might even be great to know what I'm flying.
These contrived scenarios aren't real. People ask them assuming a lot of stuff and want to know "What would you do?" They're common on written tests but those tests are taken knowing the assumptions the test giver is operating under. I can't guess yours.
Airspeed is going to be affected by the pitch change, if you're talking fixed-wing. That's a given.
If you were already fast due to the downward deviation, great. You had a little extra energy in the bank. Take it out and spend it. If you're going too slow you're going to have to add power to hold level flight.
Maybe you just plopped me into a helicopter and I need to pull collective and add power?
Maybe I'm in a giant transport category airplane and significant inertia is involved and must be taken into account? (Or as our transport category guy joked, the auto throttles or autopilot just failed?)
Maybe I'm seeing an instrumentation failure?
Maybe I'm flying a twin with one caged and losing airspeed puts me below blue-line? (Better not climb. Descent may be the only option left.)
I can't help it if my imagination can fill the void of information given with a whole lot of scenarios, good and bad, that could be faced in the real world by different pilots of different craft, and are. It's a "choose your own adventure" story.
I get the feeling from the personal attack you have a more specific scenario in your mind's eye, but didn't articulate it. That's no problem, but the answers will vary wildly with the scenarios we can all imagine.
Did we even determine if we're IMC? What can I see out the window? (I assume we're IMC, but assumptions in flying are generally bad news.)
There are even those who'd say, "If I'm a dot low, I'll just fly the whole thing a dot low." Most of us would find that very foolhardy, but he'd survive it since he's still in the protected zone of the ILS. He'd also hit DH sooner and a little further away from the airport, and lose a chance of seeing the airport, perhaps.
Is that answer more to your liking? I'm not trying to tick you off. Sheesh.
Low? Go up. That covers it I guess.
