Narrative:

I am an ATC controller at the manchester, nh, airport. On nov/wed/02, I was working the local control position from XA46 to XB10. At approximately XB15Z, a B757 came on frequency tracking the runway 6 ILS approach. I cleared the aircraft to land with a wind check from the FAA wind speed indicator reading 5 KTS. The aircraft was in the flare, over the runway, when I observed a severe oscillation on the wings. The pilot initiated a go around and stated he encountered a 'shear' of 15 KTS at 50 ft above the runway. The aircraft was vectored back onto the runway 6 ILS final and landed without incident. As a comparison, the northwest ASOS wind instruments were indicating 020 degrees at 15 KTS and subsequently a speed of 11 KTS gusting to 18 KTS. The pilot of flight could have benefited from accurate wind data. I believe the FAA wind equipment is inadequate for correctly measuring the field conditions. 1 yr ago, the direct-read FAA wind instrumentation was relocated for construction. Shortly thereafter, controllers noticed a significant difference between FAA and northwest ASOS wind speeds under certain conditions. Those are when the wind direction is from the northwest through the northeast. The new location for the FAA wind instrumentation appears to be sheltered by trees and buildings (on the north side). FAA management and facilities were informed in nov/01. The response has been 'the equipment is not OTS.' a locally adapted procedure was created in oct/02, to subjectively switch between FAA and northwest instruments. This solution is ambiguous at best and a continuing hazard to aircraft. The FAA equipment should be moved immediately, before a crash occurs. Also, the addition of LLWS measuring equipment would be a significant safety improvement to the airport. Air carrier operations have increased steadily over the last 4 yrs. Callback conversation with reporter revealed the following information: reporter stated the airport construction is scheduled for completion in the summer of 2003. He said he has been told by management that the wind equipment will then be moved back to the original site. He said the tower controllers have no confidence in wind readings coming from the temporary site and want the equipment moved back. Management has told the controllers that the temporary site is legal and the readings are correct. Controllers are allowed to issue ASOS readings to pilots when there are north winds. Reporter said he has filed a ucr, but has not received a response.

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Original NASA ASRS Text

Title: ATCT LCL CTLR AT MHT CLAIMS THE WIND EQUIP, MOVED BECAUSE OF CONSTRUCTION, IS NOT PROVIDING ACCURATE READINGS.

Narrative: I AM AN ATC CTLR AT THE MANCHESTER, NH, ARPT. ON NOV/WED/02, I WAS WORKING THE LCL CTL POS FROM XA46 TO XB10. AT APPROX XB15Z, A B757 CAME ON FREQ TRACKING THE RWY 6 ILS APCH. I CLRED THE ACFT TO LAND WITH A WIND CHK FROM THE FAA WIND SPD INDICATOR READING 5 KTS. THE ACFT WAS IN THE FLARE, OVER THE RWY, WHEN I OBSERVED A SEVERE OSCILLATION ON THE WINGS. THE PLT INITIATED A GAR AND STATED HE ENCOUNTERED A 'SHEAR' OF 15 KTS AT 50 FT ABOVE THE RWY. THE ACFT WAS VECTORED BACK ONTO THE RWY 6 ILS FINAL AND LANDED WITHOUT INCIDENT. AS A COMPARISON, THE NW ASOS WIND INSTS WERE INDICATING 020 DEGS AT 15 KTS AND SUBSEQUENTLY A SPD OF 11 KTS GUSTING TO 18 KTS. THE PLT OF FLT COULD HAVE BENEFITED FROM ACCURATE WIND DATA. I BELIEVE THE FAA WIND EQUIP IS INADEQUATE FOR CORRECTLY MEASURING THE FIELD CONDITIONS. 1 YR AGO, THE DIRECT-READ FAA WIND INSTRUMENTATION WAS RELOCATED FOR CONSTRUCTION. SHORTLY THEREAFTER, CTLRS NOTICED A SIGNIFICANT DIFFERENCE BTWN FAA AND NW ASOS WIND SPDS UNDER CERTAIN CONDITIONS. THOSE ARE WHEN THE WIND DIRECTION IS FROM THE NW THROUGH THE NE. THE NEW LOCATION FOR THE FAA WIND INSTRUMENTATION APPEARS TO BE SHELTERED BY TREES AND BUILDINGS (ON THE N SIDE). FAA MGMNT AND FACILITIES WERE INFORMED IN NOV/01. THE RESPONSE HAS BEEN 'THE EQUIP IS NOT OTS.' A LOCALLY ADAPTED PROC WAS CREATED IN OCT/02, TO SUBJECTIVELY SWITCH BTWN FAA AND NW INSTS. THIS SOLUTION IS AMBIGUOUS AT BEST AND A CONTINUING HAZARD TO ACFT. THE FAA EQUIP SHOULD BE MOVED IMMEDIATELY, BEFORE A CRASH OCCURS. ALSO, THE ADDITION OF LLWS MEASURING EQUIP WOULD BE A SIGNIFICANT SAFETY IMPROVEMENT TO THE ARPT. ACR OPS HAVE INCREASED STEADILY OVER THE LAST 4 YRS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THE ARPT CONSTRUCTION IS SCHEDULED FOR COMPLETION IN THE SUMMER OF 2003. HE SAID HE HAS BEEN TOLD BY MGMNT THAT THE WIND EQUIP WILL THEN BE MOVED BACK TO THE ORIGINAL SITE. HE SAID THE TWR CTLRS HAVE NO CONFIDENCE IN WIND READINGS COMING FROM THE TEMPORARY SITE AND WANT THE EQUIP MOVED BACK. MGMNT HAS TOLD THE CTLRS THAT THE TEMPORARY SITE IS LEGAL AND THE READINGS ARE CORRECT. CTLRS ARE ALLOWED TO ISSUE ASOS READINGS TO PLTS WHEN THERE ARE N WINDS. RPTR SAID HE HAS FILED A UCR, BUT HAS NOT RECEIVED A RESPONSE.

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.