A lockheed P2V neptune on a fire retardant flight lost the left emergency hatch during initial climb...

Narrative:

While performing air tanker support during wild land fire suppression operations; pilot and co-pilot felt one quick shudder in aircraft during initial climb. All engine instruments checked good. All aircraft surfaces visible from cockpit checked good. Co-pilot went aft to look through astro hatch on top of aircraft to inspect for possible damage to aircraft not visible from cockpit. Co-pilot discovered left side emergency hatch missing from aircraft and upon further investigation; damage to leading edge of horizontal stabilizer likely caused by hatch departing the aircraft. Decision was made to return to airport of departure and an emergency was declared. Coordinated with the tower to drop retardant load on airport and safe landing completed with no further incident.the emergency hatch discussed was originally designed as just that; an emergency hatch to be used infrequently. During our daily operations this hatch is opened and closed repeatedly in order to facilitate communication between the ground crew and the flight crew in order to coordinate loading of retardant. It is my belief that the hatch simply became worn over time from use in such a way as to not be noticeable to the flight crew. In addition; this hatch is inspected only during annual inspection of the aircraft by maintenance. It is my suggestion and our maintenance is in agreement; that this hatch be inspected on a more regular basis; perhaps at each one hundred hour inspection.

Original NASA ASRS Text

Title: A Lockheed P2V Neptune on a fire retardant flight lost the left emergency hatch during initial climb.

Narrative: While performing Air Tanker support during wild land fire suppression operations; pilot and co-pilot felt one quick shudder in aircraft during initial climb. All engine instruments checked good. All aircraft surfaces visible from cockpit checked good. Co-pilot went aft to look through astro hatch on top of aircraft to inspect for possible damage to aircraft not visible from cockpit. Co-pilot discovered left side emergency hatch missing from aircraft and upon further investigation; damage to leading edge of horizontal stabilizer likely caused by hatch departing the aircraft. Decision was made to return to airport of departure and an emergency was declared. Coordinated with the Tower to drop retardant load on airport and safe landing completed with no further incident.The emergency hatch discussed was originally designed as just that; an emergency hatch to be used infrequently. During our daily operations this hatch is opened and closed repeatedly in order to facilitate communication between the ground crew and the flight crew in order to coordinate loading of retardant. It is my belief that the hatch simply became worn over time from use in such a way as to not be noticeable to the flight crew. In addition; this hatch is inspected only during annual inspection of the aircraft by maintenance. It is my suggestion and our maintenance is in agreement; that this hatch be inspected on a more regular basis; perhaps at each one hundred hour inspection.

Data retrieved from NASA's ASRS site as of April 2012 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	902948
Time
Date	201008
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Lockheed Corp Undifferentiated or Other Model
Operating Under FAR Part	Part 137
Flight Phase	Initial Climb
Route In Use	Direct
Flight Plan	None
Component
Aircraft Component	Emergency Exit
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 40 Flight Crew Total 13000 Flight Crew Type 2300
Events
Anomaly	Aircraft Equipment Problem Critical