B747-400 crew heard and felt 2 thumps on a maximum gross weight takeoff at ord.

Attributes
ACN	575728
Time
Date	200302
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ord.airport
State Reference	IL
Altitude	agl single value : 0
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-400
Operating Under FAR Part	Part 121
Flight Phase	ground : takeoff roll
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	575728
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	non adherence : company policies other anomaly other
Independent Detector	other flight crewa other flight crewb
Resolutory Action	none taken : anomaly accepted
Consequence	other other
Supplementary
Problem Areas	Environmental Factor
Primary Problem	Ambiguous

Narrative:

First officer takeoff, maximum weight, 7 KTS tailwind on runway 32L. Well after V1, we heard 2 thumps, felt 2 thumps, no yaw. I took my right hand from my lap and touched the throttles, didn't grab them, before I realized that we were well past V1 and there was absolutely no reason to abort. If I had aborted, we'd have gone off the runway without doubt. Pretty scary -- either my incompetence or a subject to discuss in training? No tire debris, dead animal on runway at ord, tires ok landing nrt. No apparent engine damage, no engine anomalies on gauges during incident.

Original NASA ASRS Text

Title: B747-400 CREW HEARD AND FELT 2 THUMPS ON A MAX GROSS WT TKOF AT ORD.

Narrative: FO TKOF, MAX WT, 7 KTS TAILWIND ON RWY 32L. WELL AFTER V1, WE HEARD 2 THUMPS, FELT 2 THUMPS, NO YAW. I TOOK MY R HAND FROM MY LAP AND TOUCHED THE THROTTLES, DIDN'T GRAB THEM, BEFORE I REALIZED THAT WE WERE WELL PAST V1 AND THERE WAS ABSOLUTELY NO REASON TO ABORT. IF I HAD ABORTED, WE'D HAVE GONE OFF THE RWY WITHOUT DOUBT. PRETTY SCARY -- EITHER MY INCOMPETENCE OR A SUBJECT TO DISCUSS IN TRAINING? NO TIRE DEBRIS, DEAD ANIMAL ON RWY AT ORD, TIRES OK LNDG NRT. NO APPARENT ENG DAMAGE, NO ENG ANOMALIES ON GAUGES DURING INCIDENT.

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.