F-100 wake turbulence vortex encounter behind a B757.

Attributes
ACN	300900
Time
Date	199504
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : ord
State Reference	IL
Altitude	msl bound lower : 6500 msl bound upper : 9000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ord tower : mia
Operator	common carrier : air carrier
Make Model Name	Fokker 100
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 5000 flight time type : 1900
ASRS Report	300900
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	inflight encounter other
Independent Detector	other flight crewa
Resolutory Action	flight crew : exited adverse environment
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

About 7 to 8 mi in trail of a B-757 received a strong jolt of moderate turbulence at 9000 ft, lasting less than 2 seconds. Was unable to get a word in to ATC to advise and received a second slightly lesser jolt at about 6500 ft during descent on downwind for runway 27L at ord. ATC was advised as we turned base leg. Separation of 7-8 mi remained with no other occurrences. No injuries were sustained. Callback conversation with reporter revealed the following: the reporter stated the primary cause of the problem was inadequate spacing in calm air behind the 757. He said there was nothing he did that he would have done differently were the situation to occur again. In his case, the controller did not advise him he was following a B757. He says he wishes the controller would have told him there was 757 ahead he would be following for the approach. He hit the 757 wake twice.

Original NASA ASRS Text

Title: F-100 WAKE TURB VORTEX ENCOUNTER BEHIND A B757.

Narrative: ABOUT 7 TO 8 MI IN TRAIL OF A B-757 RECEIVED A STRONG JOLT OF MODERATE TURB AT 9000 FT, LASTING LESS THAN 2 SECONDS. WAS UNABLE TO GET A WORD IN TO ATC TO ADVISE AND RECEIVED A SECOND SLIGHTLY LESSER JOLT AT ABOUT 6500 FT DURING DSCNT ON DOWNWIND FOR RWY 27L AT ORD. ATC WAS ADVISED AS WE TURNED BASE LEG. SEPARATION OF 7-8 MI REMAINED WITH NO OTHER OCCURRENCES. NO INJURIES WERE SUSTAINED. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: THE RPTR STATED THE PRIMARY CAUSE OF THE PROB WAS INADEQUATE SPACING IN CALM AIR BEHIND THE 757. HE SAID THERE WAS NOTHING HE DID THAT HE WOULD HAVE DONE DIFFERENTLY WERE THE SIT TO OCCUR AGAIN. IN HIS CASE, THE CTLR DID NOT ADVISE HIM HE WAS FOLLOWING A B757. HE SAYS HE WISHES THE CTLR WOULD HAVE TOLD HIM THERE WAS 757 AHEAD HE WOULD BE FOLLOWING FOR THE APCH. HE HIT THE 757 WAKE TWICE.

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.