Flight crew of a B737-200 overshot descent altitude due to aircraft equipment problem distraction an...

Attributes
ACN	404159
Time
Date	199806
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : odf
State Reference	GA
Altitude	msl bound lower : 27500 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : ztl artcc : zdc
Operator	common carrier : air carrier
Make Model Name	B737-200
Operating Under FAR Part	Part 121
Flight Phase	descent other
Route In Use	arrival other arrival star : star enroute airway : ztl
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 150 flight time total : 3000 flight time type : 599
ASRS Report	404159
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

This is another altitude deviation with a multitude of 'links in the chain.' this event occurred on teh 5TH leg (and final) of a three day rotation. We were en route from gso to atl. The first link in the chain involved the particular aircraft flown. My company has many B737-200 aircraft of which all but two are 'advanced' models. We were flying one of the dreaded terrible two which have the sperry sp-77 autoplt rather than the sp-177. The sp-77 has a separate flight director/autoplt where as the sp-177 is an integrated unit. The sp-77 also does not have an altitude capture feature. The second link involves our recency on this particular aircraft. Since there are only two you may only see it once or less on any given rotation. Add to this I have been on the B737 for 1 yr and you have someone who is not that familiar with this aircraft. The sp-77 and these 2 aircraft are covered in less than 2 hours with no 'hands on' training during B737 ground school. You literally learn to fly these 2 aircraft 'by fire.' the third link was an mco on my DME. The DME on my navigation radio did everything but work correctly. It did not work at all at times. It picked up the wrong DME the rest of the time. It was mco'ed 'inoperative.' I was the PF and we were on an inbound radial to foothills to join the macey 2 arrival to atl at FL310. We were subsequently cleared to FL290. As we approached foothills the captain retuned his navigation radio to the atlanta VOR. I had been using his DME to see how close we were to foothills. We were then cleared to FL280. After disconnecting the altitude hold and repeating and pointing to the altitude I was trying to look over at the captain's HSI to see where the inbound atl radial was so I could make the turn. I channelized on this as did he. The next thing I heard was the altitude alert horn go off. I immediately noticed we had passed FL275 and immediately started a correction as the captain stated 'we were cleared to FL280.' as we corrected back to FL280 center cleared us to FL240 and never mentioned our deviation.

Original NASA ASRS Text

Title: FLC OF A B737-200 OVERSHOT DSCNT ALT DUE TO ACFT EQUIP PROB DISTR AND THEN DISCOVERED THEIR ERROR AND RETURNED IMMEDIATELY. THEY WERE THEN CLRED TO A LOWER ALT.

Narrative: THIS IS ANOTHER ALT DEV WITH A MULTITUDE OF 'LINKS IN THE CHAIN.' THIS EVENT OCCURRED ON TEH 5TH LEG (AND FINAL) OF A THREE DAY ROTATION. WE WERE ENRTE FROM GSO TO ATL. THE FIRST LINK IN THE CHAIN INVOLVED THE PARTICULAR ACFT FLOWN. MY COMPANY HAS MANY B737-200 ACFT OF WHICH ALL BUT TWO ARE 'ADVANCED' MODELS. WE WERE FLYING ONE OF THE DREADED TERRIBLE TWO WHICH HAVE THE SPERRY SP-77 AUTOPLT RATHER THAN THE SP-177. THE SP-77 HAS A SEPARATE FLT DIRECTOR/AUTOPLT WHERE AS THE SP-177 IS AN INTEGRATED UNIT. THE SP-77 ALSO DOES NOT HAVE AN ALT CAPTURE FEATURE. THE SECOND LINK INVOLVES OUR RECENCY ON THIS PARTICULAR ACFT. SINCE THERE ARE ONLY TWO YOU MAY ONLY SEE IT ONCE OR LESS ON ANY GIVEN ROTATION. ADD TO THIS I HAVE BEEN ON THE B737 FOR 1 YR AND YOU HAVE SOMEONE WHO IS NOT THAT FAMILIAR WITH THIS ACFT. THE SP-77 AND THESE 2 ACFT ARE COVERED IN LESS THAN 2 HRS WITH NO 'HANDS ON' TRAINING DURING B737 GND SCHOOL. YOU LITERALLY LEARN TO FLY THESE 2 ACFT 'BY FIRE.' THE THIRD LINK WAS AN MCO ON MY DME. THE DME ON MY NAV RADIO DID EVERYTHING BUT WORK CORRECTLY. IT DID NOT WORK AT ALL AT TIMES. IT PICKED UP THE WRONG DME THE REST OF THE TIME. IT WAS MCO'ED 'INOP.' I WAS THE PF AND WE WERE ON AN INBOUND RADIAL TO FOOTHILLS TO JOIN THE MACEY 2 ARR TO ATL AT FL310. WE WERE SUBSEQUENTLY CLRED TO FL290. AS WE APCHED FOOTHILLS THE CAPT RETUNED HIS NAV RADIO TO THE ATLANTA VOR. I HAD BEEN USING HIS DME TO SEE HOW CLOSE WE WERE TO FOOTHILLS. WE WERE THEN CLRED TO FL280. AFTER DISCONNECTING THE ALT HOLD AND REPEATING AND POINTING TO THE ALT I WAS TRYING TO LOOK OVER AT THE CAPT'S HSI TO SEE WHERE THE INBOUND ATL RADIAL WAS SO I COULD MAKE THE TURN. I CHANNELIZED ON THIS AS DID HE. THE NEXT THING I HEARD WAS THE ALT ALERT HORN GO OFF. I IMMEDIATELY NOTICED WE HAD PASSED FL275 AND IMMEDIATELY STARTED A CORRECTION AS THE CAPT STATED 'WE WERE CLRED TO FL280.' AS WE CORRECTED BACK TO FL280 CTR CLRED US TO FL240 AND NEVER MENTIONED OUR DEV.

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.

Flight crew of a B737-200 overshot descent altitude due to aircraft equipment problem distraction and then discovered their error and returned immediately. They were then cleared to a lower altitude.