Altitude deviation altitude undershot. Altitude crossing restriction not met.

Attributes
ACN	253719
Time
Date	199310
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : har
State Reference	PA
Altitude	msl bound lower : 25000 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zny
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 145 flight time total : 11000 flight time type : 2600
ASRS Report	253719
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 5000 flight time type : 3000
ASRS Report	253257
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : crossing restriction not met altitude deviation : undershoot non adherence : clearance
Independent Detector	other controllera
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

At approximately XX00Z, at FL350, on the johnstown transition of the bucks 3 arrival into phl, center assigned a crossing restriction of 35 wnw of har at FL250. The first officer's VOR was on jst and captain's VOR was on har. The captain's DME was indicating a distance in excess of 100 DME when center requested a descent and informed us that the crossing restriction had not been met. The first officer's DME was switched to har and indicated 25 DME to har. The captain's DME was now reading over 80 NM to har with correct azimuth (i.e., once the first officer switched to har, it was observed that the captain's and first officer's DME indication to har were 80 and 25 NM respectively with the same azimuth). There had been no previous problems with the captain's VOR/DME and none could be found after this 1 occurrence. No conflict occurred to our knowledge.

Original NASA ASRS Text

Title: ALTDEV ALT UNDERSHOT. ALT XING RESTRICTION NOT MET.

Narrative: AT APPROX XX00Z, AT FL350, ON THE JOHNSTOWN TRANSITION OF THE BUCKS 3 ARR INTO PHL, CTR ASSIGNED A XING RESTRICTION OF 35 WNW OF HAR AT FL250. THE FO'S VOR WAS ON JST AND CAPT'S VOR WAS ON HAR. THE CAPT'S DME WAS INDICATING A DISTANCE IN EXCESS OF 100 DME WHEN CTR REQUESTED A DSCNT AND INFORMED US THAT THE XING RESTRICTION HAD NOT BEEN MET. THE FO'S DME WAS SWITCHED TO HAR AND INDICATED 25 DME TO HAR. THE CAPT'S DME WAS NOW READING OVER 80 NM TO HAR WITH CORRECT AZIMUTH (I.E., ONCE THE FO SWITCHED TO HAR, IT WAS OBSERVED THAT THE CAPT'S AND FO'S DME INDICATION TO HAR WERE 80 AND 25 NM RESPECTIVELY WITH THE SAME AZIMUTH). THERE HAD BEEN NO PREVIOUS PROBS WITH THE CAPT'S VOR/DME AND NONE COULD BE FOUND AFTER THIS 1 OCCURRENCE. NO CONFLICT OCCURRED TO OUR KNOWLEDGE.

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.