Landing aircraft came close to another aircraft over the runway.

Attributes
ACN	128848
Time
Date	198911
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sjc
State Reference	CA
Altitude	agl bound lower : 10 agl bound upper : 40
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : sjc
Operator	general aviation : personal
Make Model Name	Small Transport, Low Wing, 2 Recip Eng
Flight Phase	landing other
Flight Plan	VFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Helicopter
Flight Phase	ground other : taxi
Flight Plan	None
Person 1
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
Experience	controller non radar : 1
ASRS Report	128848
Person 2
Affiliation	government : faa
Function	controller : ground
Qualification	controller : non radar
Events
Anomaly	conflict : nmac incursion : runway non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Miss Distance	vertical : 30
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Intra Facility Coordination Failure Pilot Deviation

Narrative:

I was working local control at sjc for runways 30L and 29. An small transport had passed over the field for left traffic to runway 29. While he was on a very short final passing over taxiway B, he asked me 'what is this helicopter doing underneath me?' at that point, I looked at him on short final and observed a helicopter directly underneath the small transport, approximately 1/2-way between the surface and the small transport. I would estimate the sep was not more than 30'. When the small transport landed, I told him that he could call the tower and that he could get the # from ground control. I looked at the ground controller to point out the situation to him, and he indicated that he had taxied the helicopter out to the taxiway for a departure. I feel that I was not observant enough in watching the small transport's approach, but mostly I feel that the ground controller should have scanned the final before sending a helicopter out to a taxiway where there was the potential for an overflt.

Original NASA ASRS Text

Title: LNDG ACFT CAME CLOSE TO ANOTHER ACFT OVER THE RWY.

Narrative: I WAS WORKING LCL CTL AT SJC FOR RWYS 30L AND 29. AN SMT HAD PASSED OVER THE FIELD FOR LEFT TFC TO RWY 29. WHILE HE WAS ON A VERY SHORT FINAL PASSING OVER TXWY B, HE ASKED ME 'WHAT IS THIS HELI DOING UNDERNEATH ME?' AT THAT POINT, I LOOKED AT HIM ON SHORT FINAL AND OBSERVED A HELI DIRECTLY UNDERNEATH THE SMT, APPROX 1/2-WAY BTWN THE SURFACE AND THE SMT. I WOULD ESTIMATE THE SEP WAS NOT MORE THAN 30'. WHEN THE SMT LANDED, I TOLD HIM THAT HE COULD CALL THE TWR AND THAT HE COULD GET THE # FROM GND CTL. I LOOKED AT THE GND CTLR TO POINT OUT THE SITUATION TO HIM, AND HE INDICATED THAT HE HAD TAXIED THE HELI OUT TO THE TXWY FOR A DEP. I FEEL THAT I WAS NOT OBSERVANT ENOUGH IN WATCHING THE SMT'S APCH, BUT MOSTLY I FEEL THAT THE GND CTLR SHOULD HAVE SCANNED THE FINAL BEFORE SENDING A HELI OUT TO A TXWY WHERE THERE WAS THE POTENTIAL FOR AN OVERFLT.

Data retrieved from NASA's ASRS site as of August 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.