Flight crew set altimeter wrong in descent.

Attributes
ACN	81958
Time
Date	198802
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : gdm airport : bos
State Reference	MA
Altitude	msl bound lower : 9000 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zbw tracon : bos tower : tvc
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other descent other
Route In Use	arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Experience	flight time last 90 days : 200 flight time total : 5000
ASRS Report	81958
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 25000
ASRS Report	81895
Events
Anomaly	altitude deviation : overshoot other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were cleared from our cruise altitude to descended to 10000' from the center controller and given an altimeter setting at 29.37. I (first officer) also obtained the altimeter setting from ATIS as 29.36 and wrote it down. Upon passing 18000' I called out '37' (the captain was flying) and we both incorrectly dialed 30.37 on our altimeters. Once leveled off at what we felt was 10000' we were handed off to approach control at which time he advised us that his radar showed us at 9000'. After checking our altimeters we both realized our mistake and immediately advised ATC that we were in fact at 9000', at which time the controller advised to remain at 9000'. The fact that I (the first officer) read off an incomplete altimeter setting seems to be the major cause of this incident. The departure airport altimeter was 29.88 so it seemed more natural to dial in 30.37 rather than 29.37. It becomes very commonplace to change altimeter settings and read them off (normally the change is a small one). However, this incident shows how easy it was to be lulled into a possible hazardous situation. If the entire altimeter setting was read off and then repeated by the other pilot this probably would not have happened. There were no apparent traffic conflicts or evasive maneuvers.

Original NASA ASRS Text

Title: FLT CREW SET ALTIMETER WRONG IN DESCENT.

Narrative: WE WERE CLRED FROM OUR CRUISE ALT TO DESCENDED TO 10000' FROM THE CENTER CTLR AND GIVEN AN ALTIMETER SETTING AT 29.37. I (F/O) ALSO OBTAINED THE ALTIMETER SETTING FROM ATIS AS 29.36 AND WROTE IT DOWN. UPON PASSING 18000' I CALLED OUT '37' (THE CAPT WAS FLYING) AND WE BOTH INCORRECTLY DIALED 30.37 ON OUR ALTIMETERS. ONCE LEVELED OFF AT WHAT WE FELT WAS 10000' WE WERE HANDED OFF TO APCH CTL AT WHICH TIME HE ADVISED US THAT HIS RADAR SHOWED US AT 9000'. AFTER CHKING OUR ALTIMETERS WE BOTH REALIZED OUR MISTAKE AND IMMEDIATELY ADVISED ATC THAT WE WERE IN FACT AT 9000', AT WHICH TIME THE CTLR ADVISED TO REMAIN AT 9000'. THE FACT THAT I (THE F/O) READ OFF AN INCOMPLETE ALTIMETER SETTING SEEMS TO BE THE MAJOR CAUSE OF THIS INCIDENT. THE DEP ARPT ALTIMETER WAS 29.88 SO IT SEEMED MORE NATURAL TO DIAL IN 30.37 RATHER THAN 29.37. IT BECOMES VERY COMMONPLACE TO CHANGE ALTIMETER SETTINGS AND READ THEM OFF (NORMALLY THE CHANGE IS A SMALL ONE). HOWEVER, THIS INCIDENT SHOWS HOW EASY IT WAS TO BE LULLED INTO A POSSIBLE HAZARDOUS SITUATION. IF THE ENTIRE ALTIMETER SETTING WAS READ OFF AND THEN REPEATED BY THE OTHER PLT THIS PROBABLY WOULD NOT HAVE HAPPENED. THERE WERE NO APPARENT TFC CONFLICTS OR EVASIVE MANEUVERS.

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.