B737 lands runway 1L approximately 100 ft behind B747 departing runway 28R.

Attributes
ACN	503985
Time
Date	200001
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : las.airport
State Reference	NV
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Weather Elements	Thunderstorm
Light	Dusk
Aircraft 1
Controlling Facilities	tower : las.tower
Operator	common carrier : air carrier
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : approach
Route In Use	approach : visual arrival : on vectors
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tower : las.tower
Operator	common carrier : air carrier
Make Model Name	B747 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	climbout : takeoff climbout : initial
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time total : 16000 flight time type : 240
ASRS Report	503985
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : multi engine
Events
Anomaly	conflict : airborne critical inflight encounter : wake turbulence non adherence : published procedure non adherence : required legal separation
Independent Detector	aircraft equipment : gpws other flight crewa
Resolutory Action	controller : issued advisory flight crew : took precautionary avoidance action flight crew : exited adverse environment
Miss Distance	horizontal : 1000
Supplementary
Problem Areas	ATC Human Performance Aircraft
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

The wind at las was reported as 330 degrees at 20 KTS, gusting to 26 KTS. Thunderstorms to east and southeast of field. We were cleared for visual approach to runway 1L, and a cpr gulfstream was sequenced ahead of us (approximately 4 mi ahead). We were told to slow to 150 KTS. Tower informed us a heavy B747 was on takeoff roll on runway 25R. It was dusk, and by the time we spotted the B747, he was just about to lift off I would estimate near intersection A7. We were going to land behind him, but the distances were so close that I thought a go around would be too close with respect to his aircraft and his wake turbulence. We had an approach speed of vref +16 KTS for wind, and I suggested to the first officer flying to increase to +20 KTS and be ready for his turbulence. (We were now at approximately 200 ft.) at 50-100 ft, we hit the wake of the B747, and our aircraft rolled approximately 20 degrees. The first officer added power, corrected the roll, and landed. I think this situation was a poor decision on the tower's part. A B747 probably near maximum gross, rotating and climbing slowly over our intended landing spot, is an accident waiting to happen. We passed through his turbulence about 10 seconds behind him. A look at the airport chart will show how close those runways are.

Original NASA ASRS Text

Title: B737 LANDS RWY 1L APPROX 100 FT BEHIND B747 DEPARTING RWY 28R.

Narrative: THE WIND AT LAS WAS RPTED AS 330 DEGS AT 20 KTS, GUSTING TO 26 KTS. TSTMS TO E AND SE OF FIELD. WE WERE CLRED FOR VISUAL APCH TO RWY 1L, AND A CPR GULFSTREAM WAS SEQUENCED AHEAD OF US (APPROX 4 MI AHEAD). WE WERE TOLD TO SLOW TO 150 KTS. TWR INFORMED US A HVY B747 WAS ON TKOF ROLL ON RWY 25R. IT WAS DUSK, AND BY THE TIME WE SPOTTED THE B747, HE WAS JUST ABOUT TO LIFT OFF I WOULD ESTIMATE NEAR INTXN A7. WE WERE GOING TO LAND BEHIND HIM, BUT THE DISTANCES WERE SO CLOSE THAT I THOUGHT A GAR WOULD BE TOO CLOSE WITH RESPECT TO HIS ACFT AND HIS WAKE TURB. WE HAD AN APCH SPD OF VREF +16 KTS FOR WIND, AND I SUGGESTED TO THE FO FLYING TO INCREASE TO +20 KTS AND BE READY FOR HIS TURB. (WE WERE NOW AT APPROX 200 FT.) AT 50-100 FT, WE HIT THE WAKE OF THE B747, AND OUR ACFT ROLLED APPROX 20 DEGS. THE FO ADDED PWR, CORRECTED THE ROLL, AND LANDED. I THINK THIS SIT WAS A POOR DECISION ON THE TWR'S PART. A B747 PROBABLY NEAR MAX GROSS, ROTATING AND CLBING SLOWLY OVER OUR INTENDED LNDG SPOT, IS AN ACCIDENT WAITING TO HAPPEN. WE PASSED THROUGH HIS TURB ABOUT 10 SECONDS BEHIND HIM. A LOOK AT THE ARPT CHART WILL SHOW HOW CLOSE THOSE RWYS ARE.

Data retrieved from NASA's ASRS site as of July 2007 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.