Sky-high pressure grounds planes at OTZ
January 20th, 2012 | Carey Restino
Four planes were grounded earlier this week in Kotzebue, but for once, the cause wasn't a storm or fog. It was, in fact, high pressure — really high pressure.
Spokeswoman for Alaska Airlines Marianne Lindsey said Tuesday that at least one flight was grounded because of sky-high barometric pressure, which makes setting an altimeter impossible.
"It produces erroneous readings on the altimeter," Lindsey said.
According to Alaska pilot Deb Moseley, pilots cannot set their altimeters properly when the barometric pressure exceeds 31 inches of mercury.
By Tuesday evening, the last plane had been able to take off, and Kotzebue's high-pressure system was producing a barometric pressure reading of 30.98 inches and falling. Standard pressure is 29.92 inches.
The first flight where the problem was seen was Flight 153 on Jan. 16 after which Alaska Airlines ran a complete operations check and the systems checked out fine - other than not being able to tune the altimeter from a negative setting, Lindsey said. This also occurred on Kotzebue's Alaska Airline Flight 151 Flight 152 and Flight 153 on Tuesday. After conferring with Boeing's engineering department, they agreed with the flight crew's assessment that it was a faulty indication caused by the high altimeter readings, and authorized the company to fly the three aircraft out of Kotzebue.