The Real Reason Why There's a Tiny Hole in Airplane Windows
If you look closely at a typical passenger cabin window, you’ll see three panes, typically made of acrylic materials. The purpose of the innermost pane—sometimes called the scratch pane, but I like to call it the smudge pane - is merely to protect the next one.
The middle pane (with the breather hole in it) and the outer pane are more important. Generally speaking, as an aircraft climbs, the air pressure drops in both the cabin and the outside air—but it drops much more outside, as the aircraft’s pressurization system keeps the cabin pressure at a comfortable and safe level. This means that the pressure inside the aircraft during flight is typically much greater than the pressure outside.
It turns out that itsy bitsy hole in the bottom of your airplane window is actually a very important safety feature. It's all-too-easy to let your mind wander when you're confined to a tiny box of space while hurtling 40,000 feet in the air at hundreds of miles per hour, but rest assured: every single window on the airplane has the same hole. More officially, it's called a breather hole and it's used to regulate the amount of pressure that passes between the window's inner and outer panes. In short, the system ensures that the outer pane bears the most pressure so that if there were a situation that caused added strain on the window, it's the outside panel that gives out (meaning you can still breathe).
The breather hole also keeps the window fog-free by wicking moisture that gets stuck between the panes. After all, half the fun of an airplane ride is the in-flight scenery shots. Mystery solved.
Boeing 747- 400
I’ve been tracking down the current status of the seven Boeing 747-400 series that flew between 1990 and 2003 with Canadian registrations. Four of the aircraft (in all passenger configuration) entered the C.A.I.L. fleet beginning in 1990. Air Canada originally ordered seven but only took delivery of three (in combi configuration) in 1991 and then placed them in storage until 1993 when Air Canada was granted rights to fly Asian routes. Both airlines utilized the aircraft on the fast growing Asian market.
Following is a list of the aircraft with their original registrations and delivery dates.
C-GMWW – C.A.I.L. Fin # 881 – December 11, 1990
Last flew in the Aerolineas Argentinas fleet under registration LV-BBU until June 2012 when it was returned off lease to Ansett Worldwide. It has been stored at Pinal Airpark in Marana, Arizona under registration N278AW since June 14, 2012. 
C-FCRA - C.A.I.L. Fin # 882 – February 15, 1991 (Pictured)
Last flew in the Aerolineas Argentinas fleet under registration LV-AXF while leased from Pegasus. It has been stored since January 2012. No location available.
C-GAGL – AC Fin # 341 – June 4, 1991
Converted to all cargo configuration by Air China in 2006. Still in service with MyCargo Airlines of Turkey under registration TC-ACH.
C-GAGM - AC Fin # 342 – July 16, 1991
Last flew for Dubai Air Wing in VIP configuration under registration A6-COM. According to Planefinders.net its last flight on June 8, 2014. No information given for where it is stored.
C-GAGN- AC Fin # 343 – August 30, 1991
Converted to all cargo configuration by Air China in 2006. Still in service with Saudi Arabian Airlines on a lease from MyCargo Airlines under registration TC-ACJ.
C-FBCA - C.A.I.L. Fin # 884 – April 22, 1992
Last flew in the Aerolineas Argentinas fleet under registration LV-ALI until April 2012 when it was leased to AeroSur of Bolivia. The lease was not taken up and it was returned to Sky Holding Company. It has been stored at Pinal Airpark in Marana, Arizona under registration N971PG October, 2012.
C-FGHZ - C.A.I.L. Fin #885 - April 3, 1995
Originally assigned to Philippine Airlines, it was not taken up at the time and flew for C.A.I.L. until March of 2001 when it was then returned to GECAS. Philippine Airlines then leased the aircraft under registration C-FGHZ from December 2002 until August 2013. It is presently stored at Greenwood-LaFlore Airport in Mississippi.
Sources: Planespotters.net and Airfleets.net
Note: Captain Dennis Giguere sent along this clarification concerning the circumstances of the entry of the fleet -
The Air Canada 747-400 combis were delivered to Air Canada from storage in the Mojave Desert by newly trained Air Canada pilots in the April 1992 and entered service shortly thereafter flying to CDG / LHR and FRA. Hollis Harris had just taken over as CEO and he wanted them in service ASAP.
I was one of the newly trained captains. Half of us were trained at Boeing and the rest at NATCO in MSP. Service to Asia began in 1994 to Seoul then Osaka and finally Hong Kong as I remember.
Dennis Giguere
We thank Captain Giguere for sharing his personal experience.
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Ken Starnes has sent us a group of photos of the Aircraft Maintenance Retirement Party held at the Royal St. Lawrence Yacht Club in Dorval in 1983 which appeared in NetLetter nr 1338 and 1339, here are three more.
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This is Ron Sinclair (retiree ex-General Appearance Foreman), Mrs.Whittingstall, Mrs. Sinclair, Phil Whittingstall. |
This is Ross Watson (retiree ex Paint Shop Foreman) Micheline Poupart, Mrs. Watson, Jim Riddoch |
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Jack Stephens had sent us an e-mail he received from Don Heron regarding Don's father. He had also forwarded us some photos which appeared in NetLetter nr 1339. |
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This cartoon by Dave Mathias appeared in the "Between Ourselves" magazine issued July/August 1960.
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UK finance minister George Osborne has signaled a further rise in Air Passenger Duty (APD) in his annual budget speech. APD is charged on most passengers on flight departing from UK airports. It is one of the highest rates of passenger taxes in the world and can add as much as £146 ($206) to the price of a ticket, depending on the class of cabin chosen and the distance flown by the passenger. |
David Reynolds had this photo printed in "Horizons" February 2008 (with permission). |
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The Jordan Adventure 2016 a WACA International event being hosted by the Jordan Interline Club from May 29th thru June 3rd 2016. Deadline April 28th 2016 cost $900 USD. Full details at www.waca.org. |
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Airline Club Bahamas present their first annual "Island Dreamz" in Treasure Cay, Abaco from July 14th - 18th, 2016. Deadline April 15th 2016 cost $700 USD. Full details at www.waca.org |
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The Interline Club of Israel is pleased to invite all Interline club members to visit Israel in spring time and enjoy their "Spring Holy Land Tour" from June 3rd thru 9th 2016. Stay in Jerusalem & Tel Aviv. Visit Jerusalem Old & New city, Masada, Dead Sea, Nazareth, the Sea of Galilee & many other sites. Full details www.waca.org |
