During his takeoff roll an erj-175 first officer had to cope with jet blast from a B747 which had cr...

Narrative:

We were [waiting to takeoff] runway 28C at ord. After being cleared to line up and wait; tower crossed a B-747 at either tango or foxtrot and cleared him to the cargo ramp. After the aircraft crossed the runway; he stopped and requested confirmation he was cleared into the ramp. Tower confirmed this for him and then cleared us for takeoff. As we rolled down the runway; the other aircraft must have just started to throttle up as he was still just across the hold short line and was emitting a lot of jet blast as we passed behind him at around 120 KIAS and got a yawing action off of it as it hit our tail and a slight; momentary; wing dip from it as well. I kept the aircraft under control and we were still stable for the takeoff so we continued the takeoff since we were over 80 KIAS. We rotated maybe 1;000 feet beyond the jet blast and had no further complications. We let tower know that we got his jet blast and received only a roger in reply. This could have easily been prevented if ATC had waited a little longer to allow the heavy to adequately clear the runway before he gave us a takeoff clearance. There are wake turbulence time limits between takeoffs and landings; but the controller didn't seem to allow the proper space for the 747 to clear the runway to insure we wouldn't hit his jet blast. After that aircraft stopped; it required extra power to start moving again and we were probably right behind him whenever he resumed his taxi. If we were a smaller aircraft or were in our rotation when we hit his jet blast; we probably would have had a much harder time keeping the aircraft under control. We could also have requested a little longer hold in position to allow the aircraft to start his movement again; but seeing as it was night; we thought he had cleared the runway a little further than he had.

Original NASA ASRS Text

Title: During his takeoff roll an ERJ-175 First Officer had to cope with jet blast from a B747 which had crossed the runway and stopped prior to spooling up to continue taxi after clarifying their taxi clearance.

Narrative: We were [waiting to takeoff] Runway 28C at ORD. After being cleared to Line Up and Wait; Tower crossed a B-747 at either Tango or Foxtrot and cleared him to the Cargo Ramp. After the aircraft crossed the runway; he stopped and requested confirmation he was cleared into the ramp. Tower confirmed this for him and then cleared us for takeoff. As we rolled down the runway; the other aircraft must have just started to throttle up as he was still just across the hold short line and was emitting a lot of jet blast as we passed behind him at around 120 KIAS and got a yawing action off of it as it hit our tail and a slight; momentary; wing dip from it as well. I kept the aircraft under control and we were still stable for the takeoff so we continued the takeoff since we were over 80 KIAS. We rotated maybe 1;000 feet beyond the jet blast and had no further complications. We let Tower know that we got his jet blast and received only a roger in reply. This could have easily been prevented if ATC had waited a little longer to allow the heavy to adequately clear the runway before he gave us a takeoff clearance. There are wake turbulence time limits between takeoffs and landings; but the Controller didn't seem to allow the proper space for the 747 to clear the runway to insure we wouldn't hit his jet blast. After that aircraft stopped; it required extra power to start moving again and we were probably right behind him whenever he resumed his taxi. If we were a smaller aircraft or were in our rotation when we hit his jet blast; we probably would have had a much harder time keeping the aircraft under control. We could also have requested a little longer hold in position to allow the aircraft to start his movement again; but seeing as it was night; we thought he had cleared the runway a little further than he had.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1185359
Time
Date	201407
Local Time Of Day	1801-2400
Place
Locale Reference	ORD.Airport
State Reference	IL
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	EMB ERJ 170/175 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Takeoff
Flight Plan	IFR
Aircraft 2
Make Model Name	B747 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	Pilot Flying First Officer
Events
Anomaly	ATC Issue All Types Deviation - Procedural Published Material / Policy Ground Event / Encounter Other / Unknown

During his takeoff roll an erj-175 first officer had to cope with jet blast from a B747 which had crossed the runway and stopped prior to spooling up to continue taxi after clarifying their taxi clearance.