A fokker F28, after captain's HSI indicator replacement, was dispatched without required DME test, d...

Narrative:

On nov/xb/98, the above aircraft was ferried from YYY to ZZZ due to a #1 HSI failure, which subsequently caused a DME failure. I was informed by air carrier maintenance control that the aircraft was inbound with #1 HSI disconnected and that '#1 HSI needs to be replaced.' after the aircraft arrived, my lead mechanic and myself installed a new #1 HSI. The outboard air crew arrived at the aircraft as we started our chkout (as outlined in a step-by-step on a maintenance task card). This was a chkout to return the aircraft to CAT ii status. There were 2 problems with the chkout: 1) the 'to/from' pointer was not responding, and 2) the DME was inoperative. First I and then the outbound captain (he was observing) checked the circuit breaker panel -- none were found popped. Then I had him check his release and he responded 'no wonder, ZZZ DME is down.' we then focused on the 'to/from' pointer. After about 10 mins and pwring down the aircraft, the 'to/from' pointer responded normally. After talking with my lead, I assumed that since no circuit breakers had popped (as had happened in YYY) on the DME system when the aircraft had flown in or during the chkout, the system was probably ok, but since I had no way to confirm it (ZZZ DME down) I couldn't return the aircraft to CAT ii status. I elected to sign off the aircraft, but kept it on CAT I status. After departure and at some time during cruise, the captain realized the DME system was indeed inoperative. (He stated to me several days after that he had no problem with the planned approach, but the WX was worsening and that the departure from YYY was going to be the problem.) after discussing the situation with air carrier dispatch and maintenance control by radio, they elected to divert into XXX to make further repairs. We do not normally have DME test equipment at ZZZ. When in the past we have needed one, we have had to have the test box sent from our xyx maintenance base for a specific problem (usually on an expedite basis) and then returned. We do not have one on hand at ZZZ maintenance. The time pressure I mentioned made me hesitate to call around to different maintenance hangars at ZZZ to borrow one when I thought the system was ok.

Original NASA ASRS Text

Title: A FOKKER F28, AFTER CAPT'S HSI INDICATOR REPLACEMENT, WAS DISPATCHED WITHOUT REQUIRED DME TEST, DUE TO NO TEST AVAILABLE AND ZZZ TEST XMITTER NOT OPERATING.

Narrative: ON NOV/XB/98, THE ABOVE ACFT WAS FERRIED FROM YYY TO ZZZ DUE TO A #1 HSI FAILURE, WHICH SUBSEQUENTLY CAUSED A DME FAILURE. I WAS INFORMED BY ACR MAINT CTL THAT THE ACFT WAS INBOUND WITH #1 HSI DISCONNECTED AND THAT '#1 HSI NEEDS TO BE REPLACED.' AFTER THE ACFT ARRIVED, MY LEAD MECH AND MYSELF INSTALLED A NEW #1 HSI. THE OUTBOARD AIR CREW ARRIVED AT THE ACFT AS WE STARTED OUR CHKOUT (AS OUTLINED IN A STEP-BY-STEP ON A MAINT TASK CARD). THIS WAS A CHKOUT TO RETURN THE ACFT TO CAT II STATUS. THERE WERE 2 PROBS WITH THE CHKOUT: 1) THE 'TO/FROM' POINTER WAS NOT RESPONDING, AND 2) THE DME WAS INOP. FIRST I AND THEN THE OUTBOUND CAPT (HE WAS OBSERVING) CHKED THE CIRCUIT BREAKER PANEL -- NONE WERE FOUND POPPED. THEN I HAD HIM CHK HIS RELEASE AND HE RESPONDED 'NO WONDER, ZZZ DME IS DOWN.' WE THEN FOCUSED ON THE 'TO/FROM' POINTER. AFTER ABOUT 10 MINS AND PWRING DOWN THE ACFT, THE 'TO/FROM' POINTER RESPONDED NORMALLY. AFTER TALKING WITH MY LEAD, I ASSUMED THAT SINCE NO CIRCUIT BREAKERS HAD POPPED (AS HAD HAPPENED IN YYY) ON THE DME SYS WHEN THE ACFT HAD FLOWN IN OR DURING THE CHKOUT, THE SYS WAS PROBABLY OK, BUT SINCE I HAD NO WAY TO CONFIRM IT (ZZZ DME DOWN) I COULDN'T RETURN THE ACFT TO CAT II STATUS. I ELECTED TO SIGN OFF THE ACFT, BUT KEPT IT ON CAT I STATUS. AFTER DEP AND AT SOME TIME DURING CRUISE, THE CAPT REALIZED THE DME SYS WAS INDEED INOP. (HE STATED TO ME SEVERAL DAYS AFTER THAT HE HAD NO PROB WITH THE PLANNED APCH, BUT THE WX WAS WORSENING AND THAT THE DEP FROM YYY WAS GOING TO BE THE PROB.) AFTER DISCUSSING THE SIT WITH ACR DISPATCH AND MAINT CTL BY RADIO, THEY ELECTED TO DIVERT INTO XXX TO MAKE FURTHER REPAIRS. WE DO NOT NORMALLY HAVE DME TEST EQUIP AT ZZZ. WHEN IN THE PAST WE HAVE NEEDED ONE, WE HAVE HAD TO HAVE THE TEST BOX SENT FROM OUR XYX MAINT BASE FOR A SPECIFIC PROB (USUALLY ON AN EXPEDITE BASIS) AND THEN RETURNED. WE DO NOT HAVE ONE ON HAND AT ZZZ MAINT. THE TIME PRESSURE I MENTIONED MADE ME HESITATE TO CALL AROUND TO DIFFERENT MAINT HANGARS AT ZZZ TO BORROW ONE WHEN I THOUGHT THE SYS WAS OK.

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.

Attributes
ACN	421309
Time
Date	199811
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz
State Reference	US
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	F28 Undifferentiated or Other Model
Flight Phase	other
Flight Plan	None
Person 1
Affiliation	company : air carrier
Function	other personnel other
Qualification	other other : other
ASRS Report	421309
Person 2
Affiliation	company : air carrier
Function	other personnel other
Qualification	other other : other
Events
Anomaly	aircraft equipment problem : less severe non adherence : far non adherence : published procedure other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Air Traffic Incident	other

A fokker F28, after captain's HSI indicator replacement, was dispatched without required DME test, due to no test available and ZZZ test transmitter not operating.