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From June '96 Bronco Flyer
Neither
Rain Nor Hail Nor Dark of Night…
OV-10 Service Life
Did You Know?
Neither
Rain Nor Hail Nor Dark of Night…
Guest
Writer: Brian A. Holmes, Chief Pilot,
Washington State Department of Transportation
I was looking forward to attending the OV-10 meeting scheduled for Mather California from the first invitation by Dennis Williams (CDF). After all, those of us who operate, maintain and pilot OV-10s are a small, unique group flying a very unique aircraft and it would be good to get together with each other. Of course, the planned side trip to Reno (just for therapeutic purposes) was no deterrent either.
Finally, the long awaited day arrived. My OV-10 co-pilot and I headed for Boeing Field in Seattle and an early morning departure in the State U-8F (Queen Air) The weather was nasty with low ceilings, limited visibility, turbulence and icing conditions but it wasn't until 30 minutes after take off that things really started to go wrong. About 40 or 50 miles south of Seattle, we were bouncing in the clouds with a bit of ice on the wings when we lost ALL electronic navigation equipment. I mean, we lost everything - DME, VOR, and NDB. Fortunately Seattle Approach Control was able to primary radar our track and give us vectors back to the Seattle area where a controlled descent brought us into VFR conditions at about 800 feet. I was then able to navigate back to the airport and land safely.
Was this the end of the trip? Absolutely not! Reno (I mean the OV-10 meeting) was waiting. Since my agency owns a second U-8F Queen Air, we simply transferred our baggage and flight gear, re-filed our flight plan, and away we went.
Once more, we ran into trnuble about 50 miles south of Seattle. This time, one of the two radio systems went completely black and the other one lost navigation and the voice side started acting like a scanner. The radio went through a bunch of frequencies and finally "locked up" on a control tower 30 miles north of Seattle. Once more I was connected with Seattle Approach Control (Did someone say something about deja vu?) and they cleared me direct to Boeing Field. After I reminded them I had no navigation. they vectored me back, and even though I lost my attitude indicator at 6000 feet, we finally landed safely. If I'm anything, I'm persistent. A quick phone call booked us on commercial air to Reno where we planned to rent a car and drive to Mather. This trip was rather uneventful and we made it safely to Reno.
The adventure continued the next day as we set out early in our rental car for the 8:30 a.m. meeting in Mather. Would you believe we met the absolutely worst storm northern California has experienced in recent years? Traveling at that gawd awful hour, we faced driving rain, winds of 60+ miles per hour, hail and thunderstorms followed us up and over the infamous Donner Pass. Sacramento made national television that night hecause of the severe weather. In spite of downed traffic signals, accidents in all lanes and frustrated motorists, we made the meeting (only an hour or two late.) The meeting was absolutely great - well organized, well attended. and most productive. Many, many thanks go to our absolutely great and professional hosts led by Dennis Williams of the California Department of Forestry!
Driving back to Reno, we ran into a granddaddy of winter snowstorms which delayed our flight several hours. Of course, when we finally got home to Seattle, the bad weather had followed us and winds of 100 miles/hour hit Washington. To my fellow OV-10 operators, let me say I'm looking forward to seeing you at the next meeting. But Dennis, I got the message! If you don't want me to come to Mather again, just tell me.
As many of the OV-10s remaining in service approach or exceed 10,000 flight hours total time the question of service life should be considered Most current users wish to operate their aircraft another 2,000 to 4,000 flight hours or ten to twenty years. The original intended service life of the OV-10 (7,500 flight hours ) was extended in the 1970s and 1980s. This extension is based on studies conducted under contract by Rockwell International which analyzed data compiled from the military operators.
Two studies were conducted by Rockwell International to answer questions regarding the extension of the service life of the OV-10. The first study was a formal Aircraft Structural Integrity Program (ASIP) performed under contract for the U.S.AF over a multi-year period in the 1970s This study considered the fatigue load spectrum for which the aircraft was designed and the effect of that load spectrum on cracks which might occur in critical structural components. One of the results was the identification of several such critical components. all located in the vicinity of the wing front spar or wing leading edge beam lower caps.
The second was under contract to the U.S.MC/U.S.N and evaluated the aircraft structure and systems as related to service life, maintenance level, and the ability to maintain and support the components throughout the extended years. The primary structure of the airplane is service life oriented and the study projected a service life ofat least 15,000 flight hours provided certain improvements were accomplished and the aircraft continued to be operated within the parameters established by the flight manual. The improvements were identified so as to enable the U.S.MC to attain the extended service life goal with a minimum of service related problems, and without excessive maintenance and resultant loss of aircraft availability/capability. Rockwell delivered the last Service Life Extension Program (SLEP) kit containing parts to effect these improvements to the U.S.MC in 1992 for installation on their OV-10D aircraft.
During 1989 and 1990, the U.S.AF conducted a corrosion refurbishment program on 24 of their OV- 10A aircraft. This program was similar to the U.S.MC SLEP but addressed additional problems including extensive wing rework (almost to the point of reskin- ning),corroded armor panels, reworking the vertical stabilizer skins, and reworking the cargo floor and belly skins. A list of aircraft which were processed through the Ogden Air Logistic Center OV-10 refurbishment appears at the end of this article.
All operators who plan to continue flying the OV-10 should consider incorporation of portions of the SLEP in their future maintenance plans. Some of the indications of problems are:
- Excessive
corrosion or corrosion repairs to the aircraft skin
-
Signs of fatigue in boom and fuselage side skins (soft or oil canning
skin)
-
Cracking along rivet lines, dished fasteners, or permanent buckling
of skin
-
Damage or cracking of the engine truss mounts
-
Cracks in the main landing gear actuator fitting
-
Delamination of tabs and slot doors
-
Corrosion or fatigue signs on the fuselage belly skin
- Flexing of the fuselage frames, especially left side near cargo door hinges
Many of the items addressed in the U.S.MC and U.S.AF programs were for maintainability or to improve system capability such as reinforcing areas affected by the firing of Zuni rockets. A structural improvement program can be tailored to specific aircraft and specific customer operational requirements.
Anyone desiring additional information can call Don Overfield at (909/390-2500). We would also like to hear from anyone who was involved with either the Marine Corps or Air Force programs who can provide additional information.
- The
honor of being the first Bronco to see military action goes to VMO-2,
which flew its first combat mission on 6 July 1968 from the Marble Mountain
Marine airstrip near Da Nang.
- The
first Air Force OV-10s arrived at Bien Hoa Air Base, north- east of
Saigon, at the end of July 1968.
- A
Marine squadron, VMO-6, arrived in Vietnam in November of 1968 and operated
out of Quang Tri in the northern provinces of South Vietnnam.
- Nicknamed
the `Black Ponies', the Broncos of the Navy Light Attack Squadron Four
(VAL-4) crisscrossed the Delta in support of U.S. and ARVN forces between
March 1969 and April 1972.
- When the war in Vietnam became more unpopular in the U.S., Bronco operations diversified to in- clude sensor drops along the Ho Chi Minh Trail, night interdiction over Laos and Cambodia using `Starlight' scopes and FAC, strike and convoy escort missions during the Cambodian invasion in 1970.
