Need help with formula to calculate totals, messed up by repeated dates -FlightDuty Period

Hi, everyone. I am a flight dispatcher who is having difficulty with a Flight Duty Period tracking sheet. I need a formula which gives me the total hours done by a pilot (column H) in the PREVIOUS 'x' days.

I have attached the excel file, in black font are raw data which I enter daily. Please download file and open the FDP tab from the file and goto cell Z78.

Basically I need a formula in cell Z78, which checks up the date on column D78 and selects a date range of the PREVIOUS 'x' days from the date in D78 (in this case 7 days) and give a sum of hours from the adjacent cells in column P.

Please note that I want the formula to automatically check the cells in column D for the dates, not manually select the dates, because pilots do one flight per day sometimes and it is never same. Formula should be able to be used for other pilots too.

Repeating dates on column D is making it complicated for me, I am sure you guys would be able to help. Please reply at your earliest convenience.

Thank you for the prompt reply brother. You got me exactly what I needed, that formula works! Somehow I needed to change the formula to deduct 6 from D78, not 7. Deducting 7 gives a range of 8 days. Somehow I got it. 58:10 was the answer expected.

One more thing to automate this sheet, can you explain me how to generate a separate tab like "FDP" for each Instructor (in column H) inside this sheet so that every flight is sorted by date. Is it possible??? You can use the same excel file for explanation.

I think I have wasted a lot of years not joining this forum, we have a lot of help here. Thanks