'unexpected trip' is correct and can be used in written English.
For example: Last weekend, I was surprised by my husband with an unexpected trip to Paris.
Mr. Trump's unexpected trip to Mexico was timed to steer attention from his significant shifts on immigration policy.
Mr. Peralta says he was interested in buying the Angels even before the team's unexpected trip to the World Series.
Another Unexpected Trip Aboard Air Force One Mr. Obama's six-hour visit ended exactly a year after Osama bin Laden was killed in Pakistan.
It has been quiet at Shifting Careers this week because I took an unexpected trip to Florida for a death in my family.
North Korea's leader, Kim Jong-il, prompted speculation that he will soon anoint a successor by making an unexpected trip today to the country's main ally, China.
An element of surprise is in this week's mix - noisy, unconventional folks (don't bother bickering with them) or an unexpected trip.
In short, she took few unexpected trips, except the one to Lenox Hill Hospital from which she did not return.
This is a slight miss on a few marks, which in the grand scheme of things might not be that big of a deal — if only an unexpected trip-up as the tide seems to have turned as to whether Apple can keep growing.
However, it is not known if laboratory training would benefit less healthy older adults or if it would translate into fewer falls from unexpected trips and slips in real life settings.
Plus throw in every possible side effect you could imagine that resulted in almost a dozen unexpected trips to the ER.
As the condition of the perturbation is unknown and therefore more difficult to foresee and thus to create a preprogrammed reflex pattern, this method may better resemble real life conditions such as unexpected trips or slips during patient handling.
