Sustianing or Sustaining: How To spell?

The word Sustianing is misspelled against Sustaining, which is present continuous of "Sustain"

Word contains consecutive vowels 'AI' in between alphabets sust & ning is misspelled as 'IA'
Wrong Spelling:  sust-ia-ning 
Correct Spelling:  sust-ai-ning 
Check more misspelled words of Sustaining to spell it correct.

You might be interested to know

Thermovoltiac or Thermovoltaic?

Uncertian or Uncertain?

Viamure or Vaimure?