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Civil Bronco Operator Overview2019-01-09T20:38:26+00:00
The National Aeronautics and Space Administration operates several OV-10s of various models for aeronautics research. These aircraft previously flew with both the U.S. Air Force and Marines, although one A model was officially a Navy machine that had been flown only by North American for testing. Another airframe is the first production OV-10A. NASA Broncos have operated from the Lewis Research Center (now known as Glenn Research Center) in Cleveland, OH since early 1984. Number N524NA has flown out of Langley Research Center in Hampton, VA since Sept. 3, 1991. The USAF has also participated in many joint research projects with NASA, as has the Bose Corporation.

Primary areas of research involving the OV-10 at Glenn Research Center are related to noise and acoustical research, while at Langley OV-10 research has been centered around wake vortex research and now has moved to the CERES atmospheric research program. For the aeroacoustic roles, the ability to easily switch the engines on a Bronco to produce any combination of propeller rotation directions between the two engines allows for research to be performed that would be more difficult with other airframes. In addition, the OV-10’s propellers always turn at 2,000 rpm, and it has been written that the noise level remains constant whether you are sitting on the ramp at idle or are cruising at maximum speed. In addition to measuring acoustical characteristics inside and outside of the airplane, the Bronco has been used to test airborne voice recognition systems. The wake turbulence research involved flying through the wingtip vortex from a 737. We have vidoes of this and hope to someday convert them to a downloadable format. The CERES program, described more below, involves fitting several unusual pods carrying equipment to measure the atmosphere.

Image of voice test program patch courtesy Brad Byron. Click for larger image: 
Image of CERES program patch courtesy Lil Birdie (nunya-dam-bidness@we_aint_tellin.net)

At least one aircraft is in the traditional clean white and blue NASA markings, while most of the other Broncos are still in their military colors and simply have N-numbers and a few other markings added and the service markings painted over. Externally at least, these aircraft are largely unchanged from when they were in military service. The OV-10s large cargo area provides a lot of room for instrumentation packages, and several aircraft have had large removable instrumentation booms added externally to the nose and wings to gather data.

Beginning in 1972, NASA also used the third YOV-10A prototype (registered N718NA, BuNo 152881) to test slowflight systems, including a very unusual system to drastically increase slow-speed performance. This included a large hydraulically-spun rotating cylinder at the leading edge between the added Fowler flaps and wing, which spun between 12-14,000 RPM. Lycoming T-54 turboprop engines, producing more than 1,000 shp each, were fitted with 10-ft, 4 blades composite props. The engines were interconnected by a driveshaft in case of an engine failure, and the aircraft had a short 30-foot wing. The aircraft could fly at 47 knots, but became unstable near 30. This aircraft flew out of Ames Field in California and has been described in Combat Aircraft magazine (Sept. 99) and FlyPast (May 99). This plane is visible in the OV-10 Bronco in Action book and by the summer of 1999, had been completely restored to its original off-the-assembly-line configuration by Richard Rice’s team at the Yankee Air Museum, notably with the help of NASA-Lewis’s chief Bronco pilot Bill Rieke and NA test pilot Ed Gillespie.

NOTE #1 Some NASA documents mistakenly refer to the “OV-1 OA” Aircraft.

NOTE #2 On March 1, 1999, Lewis Research Center officially changed its name to the John H. Glenn Research Center at Lewis Field. We have implemented the changes recommended by NASA to ensure that links still work with the new domain name… for an undetermined period the old domain (lerc.nasa.gov) will still work, but I have already converted all addresses here to the new domain (grc.nasa.gov)

HERE WE GO AGAIN!! Brian Nicklas of the National Air and Space Museum’s Archives Division has done some research on NASA’s numbering scheme, and shares it with us:

All NASA civil registrations are of the form NxxxNA, where xxx is the number as described below:

4xx = Wallops
5xx = Langley
6xx = Lewis (nee Glenn)
7xx = Ames (Moffett Field)
8xx = Dryden (aka Edwards)
9xx = Johnson (Ellington Field)

Thus, N524NA is assigned to Langley. Why it skips 1xx, 2xx,and 3xx, we don’t know.

To add to the confusion is the NASA negative numbers used to designate NASA photographs. Langley uses L as a prefix. Lewis couldn’t use L, and Goddard uses G, so nothing there for Glenn, so they end up using C for Cleveland. Of course, some places add a C for color, so this muddies the water. Headquarters H – uses Year-Designator-Number as in 99-H-123 or color 99-HC-123. Johnson got their photos from starting at Langley as the

At least one aircraft is in the traditional clean white and blue NASA markings, while most of the other Broncos are still in their military colors and simply have N-numbers and a few other markings added and the service markings painted over. Externally at least, these aircraft are largely unchanged from when they were in military service. The OV-10s large cargo area provides a lot of room for instrumentation packages, and several aircraft have had large removable instrumentation booms added externally to the nose and wings to gather data.

Beginning in 1972, NASA also used the third YOV-10A prototype (registered N718NA, BuNo 152881) to test slowflight systems, including a very unusual system to drastically increase slow-speed performance. This included a large hydraulically-spun rotating cylinder at the leading edge between the added Fowler flaps and wing, which spun between 12-14,000 RPM. Lycoming T-54 turboprop engines, producing more than 1,000 shp each, were fitted with 10-ft, 4 blades composite props. The engines were interconnected by a driveshaft in case of an engine failure, and the aircraft had a short 30-foot wing. The aircraft could fly at 47 knots, but became unstable near 30. This aircraft flew out of Ames Field in California and has been described in Combat Aircraft magazine (Sept. 99) and FlyPast (May 99). This plane is visible in the OV-10 Bronco in Action book and by the summer of 1999, had been completely restored to its original off-the-assembly-line configuration by Richard Rice’s team at the Yankee Air Museum, notably with the help of NASA-Lewis’s chief Bronco pilot Bill Rieke and NA test pilot Ed Gillespie.

NOTE #1 Some NASA documents mistakenly refer to the “OV-1 OA” Aircraft.

NOTE #2 On March 1, 1999, Lewis Research Center officially changed its name to the John H. Glenn Research Center at Lewis Field. We have implemented the changes recommended by NASA to ensure that links still work with the new domain name… for an undetermined period the old domain (lerc.nasa.gov) will still work, but I have already converted all addresses here to the new domain (grc.nasa.gov)

HERE WE GO AGAIN!! Brian Nicklas of the National Air and Space Museum’s Archives Division has done some research on NASA’s numbering scheme, and shares it with us:

All NASA civil registrations are of the form NxxxNA, where xxx is the number as described below:

4xx = Wallops
5xx = Langley
6xx = Lewis (nee Glenn)
7xx = Ames (Moffett Field)
8xx = Dryden (aka Edwards)
9xx = Johnson (Ellington Field)

Thus, N524NA is assigned to Langley. Why it skips 1xx, 2xx,and 3xx, we don’t know.

To add to the confusion is the NASA negative numbers used to designate NASA photographs. Langley uses L as a prefix. Lewis couldn’t use L, and Goddard uses G, so nothing there for Glenn, so they end up using C for Cleveland. Of course, some places add a C for color, so this muddies the water. Headquarters H – uses Year-Designator-Number as in 99-H-123 or color 99-HC-123. Johnson got their photos from starting at Langley as the “Space Task Group”, so they use S.

This is NASA Aircraft 524, which has been based at Langley Research Center in Hampton, VA since Sept. 3, 1991. It is a very nice-looking machine if you ask me. This aircraft is formerly USAF serial 67-14687 and was last assigned to the 507th Tactical Air Control Wing at Shaw AFB. One of our sources within the NASA network tells us:
524 was delivered to Langley by the military for use as a airborne test system. One of its current experiments is called CERES (Clouds & the Earth’s Radiant Energy System) … Langley flew 5 data flights in March (1999) with 524. We had a few maintenance problems (#1 prop change, #1 inverter, VHF/AM) but she performed like the lady she is. Some new sensors that are being added include a F-16 drop tank that has been modified with bi-fold doors to protect the down looking sensors and cameras [contained within] until airborne. An enclosure for the up-looking sensors and cameras is being built that will look similar to the jet pod that was on the German OV-10.
See the other entries for pictures of the pods. This particular aircraft has an info sheet (with this picture) at the URL http://atopsun.larc.nasa.gov/oeb/ov10.html. Believe it or not, it originally took me MONTHS of searching to find this, just because there is SOOOOOOOOOOO much stuff on the “Billlionz and billlionzz” of NASA Web sites, as Sagan would have said. (Thanks to NASM’s Brian Nicklas for additional info on 524’s history.)

This is a very commonly-seen photo, as NASA OV-10 photos go. It’s the same one you find in the Squadron-Signal book, or you can do like I did and contact NASA to send you an original print. Very clean-looking aircraft!!! I got this graphic from the URL http://mohawk.larc.nasa.gov/ov10.html Original prints of this photo and photos of NASA Numbers 615 and 636 were sent to me by the joint efforts of Mr. Brian Beaton and Mr. David DeFelice (thanks again guys!!!)

This is NASA Aircraft 524, showing off the CERES pods as of November 1999. Our source tells us, “This is the interim flight configuration. We’ll have a slightly different look in the spring.” Can’t wait to see more…

A picture of 524 in the hangar, with 636 in the background (636 is now just used to keep 524 flyable.) This picture was taken before the CERES pods were added.

Head-on view of 524 showing the new pod. That’s not an instrumented airflow probe, that’s actually the experimental weapon developed in the unsuccessful Pave Pogostick program.

Our little birdie passed along this picture of 524, with a new addition (as of July 1999)… two pods used for the CERES (Clouds & the Earth’s Radiant Energy System) experiment. Flight tests in March 1999 were undertaken to characterize the flight characteristics of the OV-10 with the pods and adjust the designs to fit this particular aircraft. In October 1999, the real data-gathering flights begin. New sensors include an F-16 drop tank that has been modified with bi-fold doors to protect the down looking sensors and cameras (contained within) until airborne, and the dorsal enclosure for the up-looking sensors and cameras which is similar to the jet pod that was on the German OV-10B(Z) target tugs. Looks kind of neat eh?

This is a parked shot of N636NA, the photo is NASA picture C-84-1056 sent to us via Brian Beaton and David DeFelice of NASA. There is also an enlarged view of the nose of this picture available. This aircraft was the first production Bronco, and formerly participated in acoustic research. It now sits at NASA Langley as a spare parts airframe to help keep N524NA flying. This image was scanned in from an 8×10 print by Mike Whaley, but lower quality scans are available at http://www.grc.nasa.gov/Other_Groups/AFED/facilities/flight.html and http://www.grc.nasa.gov/WWW/AFED/facilities/flight.html

This is from NASA Photo C-84-1056 of OV-10A, registered as N636NA. This aircraft was the first production OV-10, and was used in the official acceptance ceremony in Columbus, OH in February 1968. The nose boom is instrumented to gather data about the free-stream airflow ahead of the aircraft, such as velocity, angle of attack and yaw via the vanes visible near the front of the boom.

David DeFelice at NASA sent me a nice 8 by 10 print of this photo which I scanned in to get this – thanks David! 🙂 Information about NASA-Lewis OV-10s and their research, as well as a lower-quality version of this picture, is available at the following URLs: http://www.grc.nasa.gov/Other_Groups/AFED/facilities/flight.html http://www.grc.nasa.gov/WWW/AFED/facilities/flight.html

(Note: I have seen this aircraft identified as an OV-10D, however to the best of my knowledge it was never upgraded to D standard and all indications are that it is about as much of an A model as you can get! If anyone knows differently, please speak up!)

This is, by the way, one of the aircraft involved in the ill-fated Combat Skewer program.

This is from the URL http://www.wl.wpafb.af.mil/flight/fcd/figp/figp1/voice/voice.htm which discusses some of the voice-recognition testing done by the USAF with NASA. The OV-10’s constant-speed, counter-rotating, interchangeable engines and props (with their resultant constant sound levels) are well suited to acoustical research work. The researchers have found that if the engines are synchronized, but are precisely 180 degrees out of phase to each other acoustically, then each engine’s sound will largely cancel out that of the other and produce a very quiet airplane!

The large, very detailed version of this picture was originally obtained from http://www.grc.nasa.gov/WWW/Photo_Lab/imagenet/images/archive/aircraft/ov10_h.jpg.

This OV-10D is NASA number 615 and bears Bureau Number 155436. It was being used for fiber-optics, 3-D audio, and speech recognition studies, but was flown to Patrick AFB and transferred to the State Dept. OV-10 program in early in 2000. This is NASA picture number C95-4434. Notice that the sponsons are removed, and it appears that foil tape has been used to cover the hole for wiring. This is an ex-Marine OV-10D+ formerly of VMO-4. Another picture of this ship can be seen in the Squadron-Signal book on pages 21, 26 and 49. I scanned this in from an 8 by 10 copy of the photo sent to me courtesy Mr. DeFelice, but I haven’t seen it on the Web yet anyplace but here (so far!) (NOTE: This entry was previously listed incorrectly as 155435.)

Neat MPEG movie showing a bit of the inside of a NASA OV-10’s cockpit and looking up through the canopy from the back seat. The description says “In air restarts of the Twin Otter’s engines were filmed from an OV-10. Filmed by Jim Sims.”
After their retirement from the military, the Bureau of Alcohol, Tobacco, and Firearms acquired 22 ex-USMC OV-10Ds for use in Anti-drug operations. Eventually the State Department acquired these aircraft and today a program to continue refurbishing OV-10D SLEP airframes for use in anti-drug missions is being undertaken. The primary contractor for the work is DynCorp, and refurbishment is taking place at Patrick AFB near Cocoa Beach, Florida. These aircraft are being fitted with liquid herbicide spray gear, and have a satellite navigational system installed to find their way through the mountainous terrain of Central and South America. They are generally painted black overall and operate both during the day and at night. The sponsons and all offensive weapons are removed for this duty. There is a large herbicide tank in the cargo area (capacity of around 410 gallons) which also doubles as fuel tank for ferry flights. The wing tanks are used to provide enough fuel for the long ranges at which these operations happen.These aircraft are registered to a fictitious company, American Warbirds Inc. (supposedly this company is actually a virtually nonexistant radio shop with no listed phone number and an address in an industrial park someplace), and most do not display any external registration numbers. There are at least two ex-BATF airframes that still are in the original color scheme of red and white trim over glossy black (The Squadron-Signal book claims it is “Law Enforcement Blue” but it looked black to me from a few hundred yards away.) The aircraft I am aware of are based at Patrick AFB, one bearing U.S. Civil registration number N472AW. As of February 1998 this aircraft did not have spray gear installed, and it appears that it is at Patrick for either testing or proficiency duty, rather than being committed to anti-drug missions elsewhere. These missions are dangerous, as evidenced by a recent contact I have had with people at DynCorp based on the previous version of these pages (which didn’t even include any pictures of DOS / BATF Broncos). They were asking if I knew where they might be able to find or have produced bulletproof OV-10 canopies… seems that some of theirs had been shot out during missions and they wanted to get a little more protection!! At the 1997 Patrick AFB Open House where the detail pictures below were taken (by yours truly), the DynCorp pilot in attendance told me that they were seriously considering using unarmed A-10s for the spraying role… would that be quite a sight or what?

My Visit to the State Dept. Maintenance Facility – Report and Pictures!!

The February 1998 issue of AIR International magazine contained an article about the 31st annual NAAA (National Agricultural Aviation Association) convention in Las Vegas, NV in December 1997. Included in the article was a picture and information about a State Department Bronco that was in attendance. The aircraft was an OV-10D, formerly USMC 155474, and bears the civilian registration N16854. The article states that the operating company is Eagle Aviation Services and Technology Inc., based at Patrick AFB. (EAST Inc.?) and that there will be up to 20 Broncos equipped for this mission will supplement the turboprop Ayres Thrushes already used. (I remember seeing these Thrushes at other Patrick AFB Open Houses, and I believe they were actually equipped with machine guns.) The company was reportedly at the convention to recruit agricultural pilots, and the Bronco’s presence caused unease among some other manufacturers.

A source who prefers to remain anonymous sends us this advertisement that has appeared in Ag Pilot International Magazine for the past year or so prior to March 1998:

SEATS/JOBS AVAILABLEHighly experienced Ag pilots for year round positions. Based in Florida, will work in Central and South America. Qualifications: Commercial, Instrument, second class medical certificate. Must be proficient as a solo IFR pilot, with minimum 1500 hours of fixed wing ag time, 300 hours of which must be in turbine agricultural aircraft, 200 hours in the past 12 months. Spanish Required. A new, highly competitive, compensation package. Send resume to: EAST, Inc (Chuck Miller/Greg Smith) PO BOX 254302, Patrick AFB, FL 32925 (407) 783-9860, FAX: (407) 799-3933

This source also knows somebody who at one time almost joined the program and knew a little about it, who told him that they had lost two of the Thrushes to suspected ground fire, and at least one of the shoot downs was fatal. This is definitely not a routine crop-spraying job.

COBRO, one of the organizations that support the State Department operations, posted a bit of relevant news in October 1998 on their website (http://www.cobrocorp.com/new.html):

COBRO a winner in the State Department, INL Contract:
Cobro was recently awarded a subcontract to continue providing Logistics information management support to the Bureau of International Narcotics and Law Enforcement Affairs. COBRO is responsible for reporting operational, maintenance and logistics data on over 70 aircraft operating throughout South and Central America. The period of performance is through 2002.

There was an EXCELLENT article on these Broncos and what they do as the feature story in the May 10, 1998 Florida Today newspaper (Melbourne, FL.) I am trying to obtain official permission to reprint it here as we speak, and will post it regardless (hey they were notified) when I finish typing it up.

Soldier of Fortune magazine printed an article about the drug-spraying Broncos as the cover story in the September 95 issue. They even put a Bronco on the cover (WIDTH=569 HEIGHT=778 SIZE=221KB). I have not been able to find and read this article myself; however I found a summary posting at the URL http://www.qnx.com/~glen/deadbeef/269.html. It’s interesting if you’re into conspiracy theories and such, the veracity of some of the claims by the magazine and the author of that URL is unknown (and in my opinion probably highly suspect.) It’s old data by now anyway.

There are many shots of a DOS Bronco in Chuck Burin’s Bronco Fest 99 pictures, as well as from my own visit to the State Department’s maintenance facility.

OV-10D front cockpit, seen at the Patrick AFB Open house in April 1997.

OV-10D rear cockpit, seen at the Patrick AFB Open house in April 1997.

OV-10D front cockpit, seen at the Patrick AFB Open house in April 1997.

OV-10D rear cockpit instrument panel, seen at the Patrick AFB Open house in April 1997.

OV-10D left nose, seen at the Patrick AFB Open house in April 1997.

The bar immediately in front of the windscreen is actually a satellite guidance system display. A friend of this site who prefers to remain anonymous describes its operation like this:
Another bit of info, the “lightbar” in front of the windshield is primarily used during the spray runs. Basically, what you do is fly one pass on each edge of the sector you are going to be spraying. The GPS system remembers where each pass began and ended, it then has a reference to work with. Depending on how you program it, swath width (how wide the spray pattern is), style of turn to be used (racetrack pattern, left and right turns, etc), it will then determine your course to fly for each spray path. Pretty standard equip on most spray planes these days.
The white antennas on the top of the booms are for this system.

This is someone performing a faith healing on the Bronco. (Somebody had surreptitiously dumped a bucket of old used Propwash on it, which appeared to be making the plane hit more air pockets.) Moments later an unspeakably bright light descended out of the sky, the plane rose vertically off the ground and spun around in midair, and we heard a deep voice from on high saying “It is done, go forth and stall no more.”

OV-10D, seen at the Patrick AFB Open house in April 1997.

OV-10D, seen at the Patrick AFB Open house in April 1997.

The OV-10 has some of the strongest landing gear ever put on an airplane. You should see the video of the infamous Tank Test Track operations. Broncos have taken off and landed on a tank test track that will stop a tank at 8 mph and a car at 13 mph… as I recall, the sinusoidal undulations on the test surface were about 36 inches apart and 18 inches high. During the initial testing of the OV-10, Ed Gillespie took off and landed from this thing many times! The video is almost painful to watch. The nose gear is steerable, however asymmetrical thrust is normally used to steer on the ground.

Right main gear wheel well.
DOS – Patrick AFB airshow pics, April 1997 – Tail Area
Inside left fin of OV-10D, seen at Patrick AFB Open House in April 1997.

Inside left fin and stabilizer of OV-10D, seen at Patrick AFB Open House in April 1997.

Right fin and stabilizer of OV-10D, seen at Patrick AFB Open House in April 1997.

The OV-10 has an interesting slotted flap system. Notice the “airscoop” that is lowered along the bottom surface of the leading edge to force air into the flap slot when the flap is down. Pictures of this feature are rare!

OV-10D flap detail.

The OV-10D, unlike the OV-10A, has special engine exhausts that mix the exhaust with the slipstream in order to reduce the aircraft’s infrared heat signature, thus making it less likely to be hit by a heat-seeking missile. The OV-10D also has larger composite props and of course larger engines (the D model has 1,040 hp Garret T-76-G-420/421 engines as opposed to the 715 hp Garrett T-76-G-410/412s used in the A model.)

OV-10D right engine prop area.

OV-10D left tail boom.

OV-10D top wing, top surface.

OV-10D left wing, bottom view.

OV-10D right wing, bottom view.

OV-10D right wing, trailing edge.
DOS – Patrick AFB airshow pics, April 1997 – Spray gear

State Dept. OV-10D spray gear, as seen from the left side, as used in April 1997.

State Dept. OV-10D spray gear, as seen from rear, as used in April 1997.

The spray system pump is wind-driven, and I have observed that it tends to spin very slowly when feathered and not in use (about 6 RPM or so at final approach speed). This is simply an off-the-shelf system such as is used for normal agricultural aircraft. There is a large tank for herbicide (41% glyphosphate… Roundup weedkiller is 17% glyphosphate) in the cargo compartment. The wing tanks are used only for extra fuel.

Chuck Burin took this picture of an OV-10D owned (at the time) by the BATF. This aircraft was formerly USMC 155417 and I believe it may be one of the ones kept at Patrick AFB now, apparently for pilot proficiency and/or flight testing. The photo was taken in Manassas, VA in January 1995 – and incidentally, it makes a great Windows wallpaper!

This in-flight photo of one iteration of the State Dept. spray gear setup comes from OV10Mech’s site. I have seen a plane that looked very similar to this one flying into the maintenance base at Patrick AFB as recently as the summer of 1998.

The federal Bureau of Land Management (BLM) used to fly a fleet of seven OV-10As as firefighting lead aircraft, using the built-in smoke system to mark the proper path for tanker aircraft to fly over the fire. They were also used for land survey work, with camera and video equipment installed. They were basically flown in a standard military condition, with deactivated ejection seats. The BLM Bronco program suffered problems with obtaining parts, and the program was deactivated early in 1999 for mostly political reasons. The BLM Broncos were transferred to the California Department of Forestry and Fire Protection (CDF), where they fly in essentially the same role, however they have been reworked and modernized extensively. See our CDF pages for more thorough information on this successful program.

Random data point:

BLM aircraft N97LM was formerly a USMC aircraft, manufacturer’s serial number 305-66M37 (The Nov. 99 issue of Warbirds International lists it as 305-66W.) It was manufactured in 1967 and carried BuNo 155426, and was a YOV-10 prototype. This plane is now a spare for the CDF Thanks to Kevin Stalder and Jack L. Durham (via Chuck Burin and Jim Hodgson.)
Here is a (probably partial) list of BLM Broncos, based on the list on the CDF page.


FAA       MANUF.       BUREAU
REG.      NO.          NO.


N646                   68-3825
N685      305-72M
N91LM                  68-3811
N93LM                  67-14615
N94LM                  63-3816 (Destroyed in crash 6/10/97)
N95LM                  67-14612
N97LM     305-66W (305-66M37?)

Group: BLM010     Description: Bruce Heise BLM pics 
The next fifteen photos come to us from an “inside source”!!! Bruce Heise is “a geologist for the National Park Service in Denver with a side interest (OK, obsession) with interesting looking aircraft.” How fortunate for us that he is also a photographer! This good series of pictures of the BLM Bronco was taken at Centennial airport near Denver Colorado in 1994 and is provided to the Gallery courtesy of the National Park Service, Geologic Resources Division. I will let Bruce tell the details in his own words (I edited it together from two different emails but the words are all his):

I am a geologist for the National Park Service in Denver with a side interest (OK, obsession) with interesting looking aircraft. The Bronco has long been one of my favorites. About 1994, when the BLM acquired several for fire fighting duties, one was converted to a “photography platform”. A variety of still and video cameras were installed and operated from the rear seat, including a video camera and a Hasselblad large-format camera installed in the clear bubble on the bottom rear of the main fuselage. The video camera was controlled by the box you see mounted on the floor of the rear seat, between the observer’s legs. He had real time control, capable of moving and panning both cameras with a small joystick. The video was displayed on the monitor.

At that time, a huge expanse of BLM land in Southern California was transferred to NPS management, now called the Mojave National Preserve. There were, and are, something like 10,000 mines, mining claims, glory holes, pits, etc, and our office [The National Park Service – MSW] was looking for a relatively fast way to inventory all of them. Although it was a Bureau of Land Management project, the Park Service office contracted with them to fly a pilot study over the Mojave Preserve trying to get a preliminary inventory of abandoned mine sites. I remembered reading in a BLM publication about the converted Bronco and we were able to contact them in Boise. The photography crew arranged to meet with us at Centennial Airport just south of Denver. We spent an afternoon with them and eventually contracted to have them perform some preliminary work over the Preserve. I know that some flights were done and we received images, but a debate over funding killed the project. The last I heard from the OAS officer in the Colorado State BLM office was that the entire concept of a air photo platform was abandoned, the photographic gear was removed, and the plane reverted back to FAC for fires. That would have been around late 1995 or early 1996.

When the plane was at Centennial, I did a pretty thorough walk around with both 35mm slides and a Hi-8 video. I’d be more than happy to share all of it with you.

All you scale model buffs out there will probably love this color scheme. Well, here is the walkaround!

This BLM OV-10A is shown at Centennial Airport near Denver Colorado in 1994. Photo provided to this site courtesy of the National Park Service, Geologic Resources Division. Photo taken (and provided to us) by Bruce Heise.

This BLM OV-10A is shown at Centennial Airport near Denver Colorado in 1994. Photo provided to this site courtesy of the National Park Service, Geologic Resources Division. Photo taken (and provided to us) by Bruce Heise.

This BLM OV-10A is shown at Centennial Airport near Denver Colorado in 1994. Photo provided to this site courtesy of the National Park Service, Geologic Resources Division. Photo taken (and provided to us) by Bruce Heise.

This BLM OV-10A is shown at Centennial Airport near Denver Colorado in 1994. Photo provided to this site courtesy of the National Park Service, Geologic Resources Division. Photo taken (and provided to us) by Bruce Heise.

This BLM OV-10A is shown at Centennial Airport near Denver Colorado in 1994. Photo provided to this site courtesy of the National Park Service, Geologic Resources Division. Photo taken (and provided to us) by Bruce Heise.

This BLM OV-10A is shown at Centennial Airport near Denver Colorado in 1994. Photo provided to this site courtesy of the National Park Service, Geologic Resources Division. Photo taken (and provided to us) by Bruce Heise.

This BLM OV-10A is shown at Centennial Airport near Denver Colorado in 1994. Photo provided to this site courtesy of the National Park Service, Geologic Resources Division. Photo taken (and provided to us) by Bruce Heise.

This BLM OV-10A is shown at Centennial Airport near Denver Colorado in 1994. Photo provided to this site courtesy of the National Park Service, Geologic Resources Division. Photo taken (and provided to us) by Bruce Heise.

This is a close-up of the cargo door, showing the camera mount underneath the fuselage. Photo provided to this site courtesy of the National Park Service, Geologic Resources Division. Photo taken (and provided to us) by Bruce Heise.

This is the video camera and protective bubble used on the Bronco, located under the rear fuselage. This photo was taken at Centennial Airport near Denver Colorado in 1994. Photo provided to this site courtesy of the National Park Service, Geologic Resources Division. Photo taken (and provided to us) by Bruce Heise.

Here is the monitor used by the camera operator to aim the camera. Photo provided to this site courtesy of the National Park Service, Geologic Resources Division. Photo taken (and provided to us) by Bruce Heise.

This is the controller for the video camera. Photo provided to this site courtesy of the National Park Service, Geologic Resources Division. Photo taken (and provided to us) by Bruce Heise.

Here is a good detail shot of the rear instrument panel. Photo provided to this site courtesy of the National Park Service, Geologic Resources Division. Photo taken (and provided to us) by Bruce Heise.

Here’s a shot of N94LM courtesy Scott Richey.

Here is a Scott Richey picture of the right-side Garrett-AiResearch turbine from an OV-10A (probably N94LM) undergoing maintenance. This view is looking outboard from the center of the aircraft. The plane was in the CDF hangar and had been rebuilt and repainted in the red/black and white colors of the CDF, as they inherited BLM’s fleet.

This aircraft is owned by the U.S. Bureau of Land Management. This picture was found at http://airtanker.com/aap/ov10.htm on the Associated Airtanker Pilots’ website, although that address now has a picture of a CDF aircraft (visible on that page.) Unfortunately I cannot make out the N-numbers clearly in this photo, but the BLM operated several A-model Broncos in similar color schemes. These aircraft were used for aerial survey work, and also as firefighting lead planes (a role that continues today, all the BLM planes having gone to CDF.) The Bronco would find a good path to fly to attack the fire, then mark it using a smoke system (originally used to help fighter pilots find the Bronco FACs during an combat.) The aerial tankers then fly along the smoke trail to drop their load accurately on the fire. Neat, eh? 🙂

This picture accompanied an article originally appearing on the Arizona Flyways magazine website – check ’em out, lots of aviation info there!!

Chuck Burin provided this original photo of BLM Bronco N93LM on the ramp, showing lots of details about this eye-catching airplane’s color scheme. In a former life I believe this aircraft was USAF number 14615.

Jack L. Durham lead us to this photo of a BLM OV-10A and a C-130 Hercules in formation.

This picture of an OV-10A crash was found at the site http://www.oas.gov/OASSAFTY/mishaps/holliste.htm. This OAS (Office of Aircraft Services) aircraft (ie, it was operated for the Bureau of Land Management) crashed on June 10, 1997, 22 miles southeast of Hollister California in VFR Flight conditions, killing the pilot, David Kyle. Official word is that it was the result of pilot error. Refer to investigation NTSB No. LAX97GA205 for more information.

On a personal note, I have been in communication with Mr. Kyle’s daughter, April Hunter, and apparently he was an extremely experienced pilot. From what I know, it was probably just a small moment of something going wrong, which goes to show that sometimes fate does bad things even to the best of pilots. However, for those of us who have flying in our blood like Mr. Kyle, it’s unthinkable not to fly. The possibility of dying young in an airplane is far better than even the thought of never knowing and experiencing the feeling of leaving the ground as often as possible!!

The California Department of Forestry and Fire Protection (CDF) flies OV-10As as firefighting lead aircraft, using the built-in smoke system to mark the proper path for tanker aircraft to fly over the fire. This is similar to the role that Broncos have with the Bureau of Land Management

Tony Agosto, a CDF employee, has provided a list of CDF airframes, which is up to date as of November 12, 1998, and has been cross-checked with the list published in the Nov. 99 Warbirds International. (Our thanks to OBA Historian Chuck “IGOR” Burin for passing the original along.)


FAA       MANUF.          BUREAU    CDF      ASSIGNED BASE
REG.      NO.             NO.       NO.


N400DF    305-122M-65     155454    A-440    Columbia, CA
N401DF    305-120M-66     155457    A-310    Hemet, CA
N402DF    305-132M-70     155459    A-210    Chico, CA
N403DF    305-148M-78     155467    A-240    Redding, CA
N407DF    305-164M-86     155475    A-430    Fresno, CA
N408DF    305-174M-90     155480    A-230    Grass Valley, CA
N409DF    305-18M-12      155401    A-330    Ramona, CA
N410DF    305-156M-82     155471    A-110    Ukiah, CA
N413DF    305-20M-13      155402    A-120    Rohnerville, CA
N414DF    305-26M-16      155405             Mather, CA
N415DF    305-68M-38      155427             CDF Spare
N418DF    305-70M-39      155428    A-340    Paso Robles, CA
N419DF    305-104M-56     155445    A-410    Porterville, CA 
N421DF    305-206M-107    155496             CDF Spare
N429DF    305-17M-11      155400             CDF Spare
N430DF    305-127A-60     67-14652           CDF Spare
N646                      68-3825            CDF Spare, ex-BLM
N685      305-72M                            CDF Spare, ex-BLM
N91LM                     68-3811            CDF Spare, ex-BLM
N93LM                     67-14615           CDF Spare, ex-BLM
N95LM                     67-14612           CDF Spare, ex-BLM
N97LM     305-66W (305-66M37?)               CDF Spare, ex-BLM

CDF acquired the two aircraft that were lost during Hurricane Andrew at Homestead AFB in Homestead, FL in 1992. Both were ex-Air Force ships that had been transferred to the Navy, numbers 683796(68-3796) and 683809(68-3809). They were at Homestead awaiting further transfer to Colombia when the hurricane hit. The roof of the hangar fell on them, breaking the tailbooms. Both are now at Mather, California and are being used for spare parts. In addition, the CDF also acquired a scrap airframe from Nellis AFB (68-3790). It had been used as a crash crew trainer for several years.

In November 1998, David Pimblett (GySGT USMC Ret.) reported that seven aircraft (155402/N413DF, 155405/N414DF, 155427/N415DF, 155428/N418DF, 155445/N419DF, 155496/N421DF, 155400/N429DF) have been moved from Tucson, AZ to Mather, CA for rework. In addition, four ships – 155405/N414DF, 155427/N415DF & 155496/N421DF, and 155400/N429DF – were flown out on 4 Nov 98. Photos are hopefully forthcoming.

The November 99 issue of Warbirds International has an article on the CDF Bronco operations and the story of the BLM OV-10As with a lot of really nice color pictures and (mostly) accurate info of the current CDF fleet.

In order to facilitate browsing and keep the size of pages down, we have broken this section up according to the registration number (the FAA-assigned N-Number) of the aircraft. N-numbers that are EVEN are grouped on the same page, ODD numbers are on another. Unknown aircraft will stay on this page.

Scott Richey’s visit to the CDF aircraft maintenance and fire response base at Mather Airport in Sacramento, CA – SHOP

Unknown OV-10 in CDF shop in the middle of a complete rebuild. Photo courtesy Scott Richey, who says: I was very impressed with the work that the CDF contractor was doing, don’t know their name. I don’t think they left anything untouched. The quality of workmanship was also extremely high. I was drooling all through the shop. I would have loved to spend a few weeks working in the shop. [CDF’s OV-10 refurbishment and maintenance contractor is San Joaquin Helicopters, whose OV-10 work is usually described as spectacular – MSW] I was also impressed with the simplicity and robustness of the OV-10 design. It’s built like a tank. The airframes should last a long time in non-military use.

Interesting shot of front cockpit. Photo courtesy Scott Richey.

Another shot of the cockpit, looking toward front, odd angle. Photo courtesy Scott Richey.

Canopy structure and looking inside the fuselage towards rear. Photo courtesy Scott Richey.

Wing tip, airfoil profile. Photo courtesy Scott Richey.

Outboard flap detail and nacelle fairing. Photo courtesy Scott Richey.

Front of nacelle boom without turbine. Photo courtesy Scott Richey.

Boom with panels removed. Photo courtesy Scott Richey.

Boom showing control cables. Photo courtesy Scott Richey.

Horizontal tail, look close, no fairing. Photo courtesy Scott Richey.

Good shot of front – note the spoilers deployed on one side. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Close-up of nose and canopy of CDF OV-10A. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Inside the front gear bay, the front landing light is visible to the right. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Detail of boom and vertical stabilizer. Photo courtesy Scott Richey.

Left aileron showing vortex generators. Photo courtesy Scott Richey.

Close up of nacelle and prop spinner. Photo courtesy Scott Richey.

Boom detail. Photo courtesy Scott Richey.

Boom and vertical stabilizer. Photo courtesy Scott Richey.

This smallish picture of an OV-10A with the marking smoke turned on was found at the very informative list of Aerial Firefighting Links at the URL http://www.sonnet.com/usr/wildfire/aerial.html Broncos were originally designed with a smoke system on the port side engine so that they would have a mechanism for fighters to easily find the FAC before an attack run. This of course has proven very useful for firefighting lead duty, where the Broncos use the smoke to mark a good path over a fire. The firebombers then can follow this smoke trail on their bombing runs.
This page includes CDF airframes registered with odd N-numbers. These aircraft are:


FAA       MANUF.          BUREAU    CDF      ASSIGNED BASE
REG.      NO.             NO.       NO.


N401DF    305-120M-66     155457    A-310    Hemet, CA
N403DF    305-148M-78     155467    A-240    Redding, CA
N407DF    305-164M-86     155475    A-430    Fresno, CA
N409DF    305-18M-12      155401    A-330    Ramona, CA
N413DF    305-20M-13      155402    A-120    Rohnerville, CA
N415DF    305-68M-38      155427
N419DF    305-104M-56     155445    A-410    Porterville, CA 
N421DF    305-206M-107    155496
N429DF    305-17M-11      155400

Quick note: there are also a few pictures of N403DF available via the Models page, in the background of a picture of a scale model of the plane.

Right front fuselage. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Right rear fuselage. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Right boom. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Here is a front view of right prop and engine nacelle and Ron Strong. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Rear of fuselage and right main gear. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Close-up of right main gear. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Interior of right main gear bay. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Interior of fuselage with auxiliary fuel tank installed. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

This OV-10A is CDF Number 24, registered as N403DF. This is a good shot of the left side cowling opened for maintenance. This photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Here is a good shot of the front office of OV-10A N403DF, CDF Number 24. Notice that the heads-up display that is normally mounted at the top of the windshield frame has been removed. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

This is an excellent detail shot of the instrument panel of CDF OV-10A Number 24, registered as N403DF. This photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

This the engine of an OV-10A, almost certainly from N403DF, on a stand for maintenance. OV-10s were known for being easy aircraft to change the engines on, in fact NASA has taken advantage of this ability to facilitate research into engine noise. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.
Scott Richey’s visit to the CDF aircraft maintenance and fire response base at Mather Airport in Sacramento, CA – RAMP – N407DF \

Scott Richey sent us a whole bunch of great pictures of some CDF Broncos (A models) that he caught while on the ramp and in the shop for maintenance. All you aspiring Bronco photographers out there, take note – these are the sort of pictures that really stand out… lots of rarely-seen, clear details. Thanks Scott!! 🙂 This is a side view of CDF OV-10A N407DF waiting for a complete rework. This photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA.

Here is a better shot of the above OV-10A. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Right fuselage and canopy of CDF OV-10A. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Details of inside of the right boom. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

This is a detail shot of the underside of the horizontal stabilizer and rudder. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Detail of vertical stabilizer and boom, controls, hinge, and the boom end. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

Shot of the right engine and prop area. Photo was taken at Mather Airport at the CDF aircraft maintenance and fire response base in Sacramento CA by Scott Richey.

This aircraft is owned by the California Department of Forestry and Fire Protection (CDF) and is a firefighting lead / spotter plane in the air attack role. According to the CDF Aerial Firefighting page they now own 5 OV-10s and will acquire 8 more in the next few years as Cessna O-2s are phased out. The excellent photo above was found on the Associated Airtanker Pilots’ neat firefighting aircraft photo gallery, specifically at the URL http://airtanker.com/aap/ov10.htm. Incidentally, this is the same photo that is found (in black & white) in the back of the Squadron-Signal book.

Bronco guru Chuck Burin also sent this excellent shot of a CDF OV-10A (Civil registration number N401DF), in formation with two S-2 firebombers. I believe that this aircraft was formerly USMC aircraft 155457.

This is CDF aircraft N401DF on the ramp. Notice the nose number is 310 in this photo, whereas it is 31 in others. A CDF air attack officer at the Redding Air Attack Base in Northern California, John S. Watt, tells us why: Our original air attack aircraft numbering scheme used two digits. So the primary aircraft out of a base would be “Air Attack 24” and secondary, call-when-needed aircraft would be 121, 122, etc. So now we use a three digit identifier to identify the primary air attack coordinator for conformity, i.e., Air Attack 240, 210, 120, 110 etc. The aircraft in your photos are the same; 31 became 310. This picture was found at the FireHogs site (A proposal to convert retired A-10 Warthogs to firebombers!!) at the URL http://www.firehogs.com/photos/cdftkrs.shtml
This page includes CDF airframes registered with even N-numbers. These aircraft are:


FAA       MANUF.          BUREAU    CDF      ASSIGNED BASE
REG.      NO.             NO.       NO.


N400DF    305-122M-65     155454    A-440    Columbia, CA
N402DF    305-132M-70     155459    A-210    Chico, CA
N408DF    305-174M-90     155480    A-230    Grass Valley, CA
N410DF    305-156M-82     155471    A-110    Ukiah, CA
N414DF    305-26M-16      155405             Mather, CA
N418DF    305-70M-39      155428    A-340    Paso Robles, CA
N430DF    305-127A-60     67-14652

Bronco guru Chuck Burin sent this picture of an OV-10A owned by the CDF, taken at Camp Pendleton on May 20, 1993. This is how it appeared before receiving the attractive white and red CDF paint scheme. This aircraft was formerly USMC aircraft 155454, but now flies with the civil registration N400DF.

Bill Kistler sent this photo of N402DF, seen on the ramp in Chico during Aug.