Attachment J-4 Presentation.pdf

FEDERAL AVIATION ADMINISTRATION

GUAM ATCT CAB REPLACEMENT

ANTONIO B. WON PAT INTERNATIONAL AIRPORT

BIDDER’S SITE VISIT: OCTOBER 30 & 31, 2024

•1

COMMENTS

• Attached are photographs of what you will encounter with your Site Survey.

• Attached are original As-built Drawings and recent drawings of the ATCT.

• Drawings 597382 and 597397 were redrawn to provide a clear detail of the Cab construction.

• In February 2020 a Replacement Glass Survey was conducted, portions of which have been expressed here and in Att. (12) February 2020 Glass Site Survey Origination Comments by

AML.

GUAM’S FAA OWNED ATCT IS THE FORMER UNITED STATES NAVAL AIR STATION LOCATED

ON THE ISLAND OF GUAM. IT WAS OPENED BY THE JAPANESE NAVY IN 1943 AND CLOSED

BY THE UNITED STATES NAVY IN 1995. DURING AND AFTER ITS CLOSURE, IT HAS

CONTINUED TO OPERATE ALONGSIDE ANTONIO B. WON PAT INTERNATIONAL AIRPORT.

REASON FOR CAB REPLACEMENT

2019-2020 GUM ATCT Cab glass has been deteriorating from hazing-over which effects the controller’s visual field and will continue. The deterioration of the laminate’s interlayer and exterior etching of glass has been on-going since the FAA acquired the ATCT from the US Navy in 1995. The Cab glass is tinted which is no longer used by the FAA and is inherently susceptible to deterioration from the tropical UV, corrosive marine atmosphere, existing glass washing system, and inadequate drainage. In February 2020 a survey was conducted to replace the glass and the survey reported that a ¾-inch structural steel sill-plate supporting the Cab and placed along the top perimeter of the Cab’s supporting concrete base wall has suffered from severe corrosion and will continue to deteriorate. The sill-plate and portions of the base wall have been exposed to typhoon-driven winds and extreme weather that have caused deep penetration and corrosion by moist marine air behind the Cab flashings and into the glass frames. A vertical overhang over the exterior face of the base wall by the sill-plate suggest that a seismic event occurred. The movement appears to have developed cracks in the face of the base wall of undetermined depth and spalling on the horizontal surface beneath the sill-plate. Cracks in the concrete cast doubt as to the structural integrity of the embedded structural reinforcement bar, i.e., corrosion and the effect on the entire base wall. The sill-plate appeared to have shifted with embedded fasteners that have corroded and has the potential to shear off the base wall. The corroding sill-plate poses a risk to the separation of mullion connections, too. The integrity of existing frame members to transmit both lateral and bearing forces to the concrete base wall appear to be compromised.

Repair or replacement of the structural steel sill-plate and concrete base wall are considered crucial prior to replacement of Cab glass and framing, therefore the only option is to replace the ATCT Cab.

•4

1995 TO PRESENT

LOOKING SOUTHWEST AT “NEW” EXTERIOR PRESURIZED STAIRWELL

LOOKING SOUTH AND WEST SIDE WITH EXTERNAL

STAIRWELL

ATCT CAB SILL PLATE CORROSION

SEE ATTACHMENT 12 FOR MORE DETAIL

ATCT CAB ROOF POSTS AND MULLION

CONNECTIONS

FORMER INTERIOR SHIPS LADDER

ACCESS TO CAB AND HVAC RETURN

Top of Ships Ladder (former access to ATCT Cab) and HVAC Return Vent from CAB to Vent in left of Photo

HVAC Return Vent Down former Ships Ladder

INTERIOR STAIRWELL CONNECTION TO CAB

Top of Stairwell Landing Stairwell Landing, Attachment Point of Stairwell to Cab.

Looking down from Cab flooring to Stairwell Landing

SUBJUNCTION CRAWL SPACE BENEATH CAB

SUBFLOOR

NOTE: HVAC, UTILITIES, MULLION DUCT PORTS

Entryway into Subjunction, top right of photo

Looking into Subjunction Level beneath Cab Subfloor and above the Tower’s 5th Floor

SUBJUNCTION CRAWL SPACE

AND ONE OF EIGHT MULLIONS

RAISED CAB FLOORING

SUBFLOOR BOTTOM LOCATED ABOVE SUBJUNCTION LEVEL AND

BENEATH RAISED CAB FLOORING

ATCT CURRENT WINDOW WASHING

SYSTEM

DRAWING REFERENCES

• Att. (1) 597375 (1953) Operations Bldg. & Control Tower

• Att. (2) 597376 (1953) Exterior North & East Elevations

• Att. (3) 597377 (1953) Exterior South & West Elevations

• Att. (4) 597382 (1954) Ops Bldg. & Control Tower

• Att. (5) 597382 (2024) Ops Bldg. & Control Tower - A001 (Redrawn)

• Att. (6) 597382 (2024) Ops Bldg. & Control Tower - A002 (Redrawn)

• Att. (7) 597382 (2024) Ops Bldg. & Control Tower - A003 (Redrawn)

• Att. (8) 597397 (1955) Control Tower Plans & Details

• Att. (9) 597397 (2024) Control Tower Plans & Details - A001 (Redrawn)

• Att. (10) 597398 (1953) Interior Stair Detail

• Att. (11) WP-D-601-40064 (1998) ZUA-ATCT Modernization and Upgrade

• Att. (12) February 2020 Glass Site Survey Origination Comments by AML