This video covers how an airline with the word pacific in its name accidentally wrote paciic on their airplane.
While very amusing, the lady in the video pronounces the mistaken ‘pasiic’ like Pacific, just without the f, like ‘pacic’, if you will.
Is that indeed the write way to say it, or does its pronunciation change? (According to the rules of English-?-)
"Paciic" is not a word, so it doesn’t have any established pronunciation.
For comparison, if the misspelling had been "pcfvc", would you expect there to be a "right" way to pronounce this sequence of letters?
Nevertheless, I think Peter Shor’s comment saying that "There are no rules […] there’s no model" [for "paciic"] is a slight overstatement. (Only "slight" because "paciic" is indeed an unusual spelling, even though it isn’t an outright violation of normal English spelling patterns the way that "Pcific" would have been.) It is possible to make some predictions about the possible pronunciation of a hypothetical word "paciic": even though there is no comparable word ending in IIC specifically, we can break the word down into even smaller constituent parts that could be analyzed using known "rules" of English spelling. The real problem with this approach is that there are too many possible models: many English spelling patterns have more than one associated pronunciation pattern, and there’s just no way to determine which is "correct" without knowing more about the word than just the spelling. (For example, nothing about the spellings of the words "cow" and "crow" tells you that they are pronounced with different vowels.)
Two parts of the pronunciation seem pretty straightforward:
Most words ending in the letters IC have the suffix -ic, which is pronounced /ɪk/. So if paciic were a word, it would probably end in the sounds /ɪk/.
It’s safe as far as I know to say that words starting with the letter P followed by a vowel letter are pronounced starting with the consonant /p/.
So the pronunciation of a word paciic would presumably be something of the form /p…ɪk/. Filling in the middle part is a bit trickier.
"puh-SIGH-ik" would be the most regular pronunciation for "paciic"
Words ending in the suffix -ic are usually stressed on the immediately preceding syllable. Following the usual correspondences between vowel letters and vowel sounds in English, this would yield the pronunciation /pəˈsaɪɪk/ "puh-SIGH-ik" (if we use an acute accent to mark stress, "pacíic"). Compare algebráic or heróic. (However, there are some exceptions to these correspondences: words ending in -eic such as deoxyribonucléic are often pronounced with a "long a" sound instead of the "long e" sound.)
I can’t think of any examples of II pronounced /aɪ.ɪ/ in existing words, but a similar situation is the pronunciation of IE as /aɪ.ɪ/ or /aɪ.ə/ in words like socíety and varíety.
Other plausible pronunciations
The rule about stress for -ic words is pretty reliable, but as I mention in my answer to a previous question, I don’t think it’s very strongly internalized for all English speakers. There are some words that sometimes are given alternative stress patterns, such as glyceric, phosphoric, cholesteric, toluic, and, most relevantly for your question, ichthyic.
Merriam-Webster, the American Heritage Dictionary and Oxford Dictionaries all agree that "ichthyic" can be pronounced with stress on the first syllable, ending in /iɪk/. (Merriam-Webster also lists a pronunciation ending in /aɪɪk/.)
If this stress pattern were applied to paciic, there are a number of other uncertainties that become relevant:
should the "ci" in the middle be pronounced as /si/ (as in calcium), or as /ʃ/ (as in special), or as /ʃi/ (as in artificiality)?
should the "a" in the stressed first syllable be pronounced as /æ/ (as in national), or as /eɪ/ (as in facial)?
Things like this give rise to a number of alternative potential pronunciations for páciic such as /ˈpæsiɪk/, /ˈpeɪsiɪk/, /ˈpeɪʃiɪk/. Note that there are real English words with similar spelling patterns that are pronounced differently by different speakers: e.g. association is pronounced by some speakers with /ʃi/, and by others with /si/, and ration is pronounced by some speakers with /æ/, and by others with /eɪ/.