Hi guys, I found this on my MEL
"OPERATIONS (O) For remarks or exception
I) 1. When dispatching with one operating pack supplied by engine bleed air on takeoff:
A. Determine V1 (MCG) based on engine bleed for packs OFF.
B. Determine takeoff performance based on packs AUTO. 2. 3. 4. 5. 6. Mel737-NG 21 p01-02 r5-5 021109 1328 Limit altitude to FL 250.
For B737-76N and B737-73V only, use only one chiller inflight.
Position the associated PACK switch to OFF.
Position the ISOLATION VALVE switch to CLOSE.
For increased air flow when the flaps are extended (takeoff and landing), use the APU to supply bleed air to the operating pack.
A. Right pack Inoperative 1) Do the Supplementary Procedure – Air Systems “No Engine Bleed Takeoff and Landing” (Refer to the Flight Crew Operations Manual).
NOTE: Keep the PACK switch to OFF and the ISOLATION VALVE switch to CLOSE.
B. Left pack inoperative – PRIOR to takeoff or landing
1) Engine No.1 BLEED air switch to OFF
2) R PACK switch to AUTO
3) L PACK switch to OFF
4) ISOLATION VALVE switch to OPEN
5) Engine No. 2 BLEED air switch to OFF
6) APU BLEED air switch to ON"
I guess that you have to make a no engine bleed take off because you must leave the inop pack switch in OFF, so the operating pack will work on high and will demand more bleed, so.... what happened if some engine fail?, you will be climbing and accelerating with less power than what the engine can really offer. Maybe this can also affect your V1 (MCG).