B737 was converted to comply with stage III noise rules. After landing, airline engineering personne...

Attributes
ACN	406721
Time
Date	199806
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : phx
State Reference	AZ
Altitude	agl bound lower : 0 agl bound upper : 0
Aircraft 1
Controlling Facilities	tracon : phl
Operator	common carrier : air carrier
Make Model Name	B737-200
Operating Under FAR Part	Part 121
Flight Phase	ground : parked
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 20000 flight time type : 2000
ASRS Report	406721
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

We operated the aircraft after the engines were modified with hush kits. The modification extended the engine inlets about 5 inches. The engine inlets were installed on the opposite engines. The aircraft was flown with the left engine inlet on the right engine and the right inlet on the left engine. This was our first aircraft to be modified and the mechanics and flight crew did not know how the engine appearance would be changed. We did not recognize the discrepancy. Pilot indicated he was accepting his airline's first converted aircraft. He did not know what the correct installation looked like. He indicated that there is a noticeable difference in cowling appearance, there is no performance difference, and that engine performance numbers may differ .01 EPR due to rounding of the numbers. Reporter suggests that the cowlings be keyed so that it is impossible to install them backwards. This analyst concurs that good engineering practice would dictate this be done.

Original NASA ASRS Text

Title: B737 WAS CONVERTED TO COMPLY WITH STAGE III NOISE RULES. AFTER LNDG, AIRLINE ENGINEERING PERSONNEL DISCOVERED THE VENDOR HAD REVERSED THE COWLING INLETS FOR ENGS #1 AND #2.

Narrative: WE OPERATED THE ACFT AFTER THE ENGS WERE MODIFIED WITH HUSH KITS. THE MODIFICATION EXTENDED THE ENG INLETS ABOUT 5 INCHES. THE ENG INLETS WERE INSTALLED ON THE OPPOSITE ENGS. THE ACFT WAS FLOWN WITH THE L ENG INLET ON THE R ENG AND THE R INLET ON THE L ENG. THIS WAS OUR FIRST ACFT TO BE MODIFIED AND THE MECHS AND FLC DID NOT KNOW HOW THE ENG APPEARANCE WOULD BE CHANGED. WE DID NOT RECOGNIZE THE DISCREPANCY. PLT INDICATED HE WAS ACCEPTING HIS AIRLINE'S FIRST CONVERTED ACFT. HE DID NOT KNOW WHAT THE CORRECT INSTALLATION LOOKED LIKE. HE INDICATED THAT THERE IS A NOTICEABLE DIFFERENCE IN COWLING APPEARANCE, THERE IS NO PERFORMANCE DIFFERENCE, AND THAT ENG PERFORMANCE NUMBERS MAY DIFFER .01 EPR DUE TO ROUNDING OF THE NUMBERS. RPTR SUGGESTS THAT THE COWLINGS BE KEYED SO THAT IT IS IMPOSSIBLE TO INSTALL THEM BACKWARDS. THIS ANALYST CONCURS THAT GOOD ENGINEERING PRACTICE WOULD DICTATE THIS BE DONE.

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.

B737 was converted to comply with stage III noise rules. After landing, airline engineering personnel discovered the vendor had reversed the cowling inlets for engines #1 and #2.