Table Interpolation Any Ideas? (tried over 20 formulas with no sucess)

[atdever]

I have attempted several formulas with no sucess. The goal is enter ALT and TAS data into the E,F <DUAL INPUT Reference>. (See line 1. below) IF(E1s value <= $A$1:$A$15 values = TRUE, THEN F1 = E1 AND F1s VALUE MATCHES <= $B$4:$B6 VALUES THEN RETURN LBS = 3.5

Any Ideas?

<Look Up Info>, <DUAL INPUT Reference>, Interoplated <Desired Output>,
A B C D E F
ALT, TAS, LBS, ALT, TAS, LBS,
1. 000, 250, 1.0, 300, 350, 3.5,
2. 000, 275, 1.5, 525, 325, 2.0,
3. 000, 300, 2.5, 500, 350, 2.2,
4. 300, 310, 2.9, 000, 225, 1.0,
5. 300, 320, 3.3, 1000, 415, 2.3,
6. 300, 350, 3.5, 1235, 425, 1.2,
7. 500, 325, 2.0, 1500, 500, 0.8,
8. 500, 350, 2.2, 1500 525, 3.1,
9. 500, 375, 2.1,
10. 1000, 400, 2.3,
11. 1000, 425, 1.2,
12. 1000, 450, 1.6,
13. 1500, 475, 0.95,
14. 1500, 500, 0.8,
15. 1500, 525, 3.1,