Aircraft aft airstair opened in flight. Flight diverted, landed without incident, injuries or damage...

Attributes
ACN	111063
Time
Date	198905
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : jfk
State Reference	NY
Altitude	msl bound lower : 26000 msl bound upper : 28000
Environment
Flight Conditions	IMC
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	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 161 flight time total : 13469
ASRS Report	111063
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

20 mins after takeoff from jfk, the aft airstairs dropped about 12'. Since we have no procedure in our manual to cover such event, we tried to contact our company maintenance departure through our dispatcher. After several frustrating mins we were unable to get a satisfactory phone patch. We then used our commercial radio frequency and again attempted a phone patch--again unsuccessful. Finally after about 20 mins, we obtained the information we needed by a 2-WAY relay by thecommercial radio operator. By this time the nearest airport was cmh. Also the 'cooper' switch which is supposed to prevent the stairs from dropping failed, I suggest that another switch of this type be installed on the opp side of the airstairs. Please call--I would like to discuss this problem. Callback conversation with reporter revealed the following: reporter states that the problem was apparently caused by a retaining spring weakness allowing the stair to become unlatched. He states that he utilized an onboard dead heading crew member to observe the stairs during the approach phase through the aft entry door. During T/D the stair fully extended and contacted the ground, but no damage occurred.

Original NASA ASRS Text

Title: ACFT AFT AIRSTAIR OPENED IN FLT. FLT DIVERTED, LANDED WITHOUT INCIDENT, INJURIES OR DAMAGE.

Narrative: 20 MINS AFTER TKOF FROM JFK, THE AFT AIRSTAIRS DROPPED ABOUT 12'. SINCE WE HAVE NO PROC IN OUR MANUAL TO COVER SUCH EVENT, WE TRIED TO CONTACT OUR COMPANY MAINT DEP THROUGH OUR DISPATCHER. AFTER SEVERAL FRUSTRATING MINS WE WERE UNABLE TO GET A SATISFACTORY PHONE PATCH. WE THEN USED OUR COMMERCIAL RADIO FREQ AND AGAIN ATTEMPTED A PHONE PATCH--AGAIN UNSUCCESSFUL. FINALLY AFTER ABOUT 20 MINS, WE OBTAINED THE INFO WE NEEDED BY A 2-WAY RELAY BY THECOMMERCIAL RADIO OPERATOR. BY THIS TIME THE NEAREST ARPT WAS CMH. ALSO THE 'COOPER' SWITCH WHICH IS SUPPOSED TO PREVENT THE STAIRS FROM DROPPING FAILED, I SUGGEST THAT ANOTHER SWITCH OF THIS TYPE BE INSTALLED ON THE OPP SIDE OF THE AIRSTAIRS. PLEASE CALL--I WOULD LIKE TO DISCUSS THIS PROB. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR STATES THAT THE PROB WAS APPARENTLY CAUSED BY A RETAINING SPRING WEAKNESS ALLOWING THE STAIR TO BECOME UNLATCHED. HE STATES THAT HE UTILIZED AN ONBOARD DEAD HEADING CREW MEMBER TO OBSERVE THE STAIRS DURING THE APCH PHASE THROUGH THE AFT ENTRY DOOR. DURING T/D THE STAIR FULLY EXTENDED AND CONTACTED THE GND, BUT NO DAMAGE OCCURRED.

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.