F35 C first deck landing
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From 1.5 YEARS ago - wot CNO finks of it all - I wonder wot he finks today?
CNO Testifies About Joint Strike Fighter Published on Jun 19, 2013
CNO Testifies About Joint Strike Fighter Published on Jun 19, 2013
"Chief of Naval Operations Adm. Jonathan Greenert testified before the Senate Appropriations Committee Subcommittee on Defense about the Joint Strike Fighter (F-35C) on June 19, 2013."
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VIDEO: F-35C First Navy Test Pilot Flight (early 2011)
Another OLDie but a GOLDie from 2011 and it flugged good.
F-35C First Navy Test Pilot Flight Uploaded on Feb 17, 2011 U.S. Navy
F-35C First Navy Test Pilot Flight Uploaded on Feb 17, 2011 U.S. Navy
"Perspective on the first Navy flight of the CF-1, the first F-35C Joint Strike Fighter variant undergoing test and evaluation at Naval Air Station Patuxent River. The F-35C is designed to the be the first stealth strike fighter for the U.S. Navy. It has larger wing surfaces and reinforced landing systems for the demanding carrier environment. Flight footage courtesy Lockheed Martin."
I have a question for anyone involved with the program. I have often enjoyed listening to friends and colleagues with F-4, F-14 and F-18 (oh, and Sea Vixen) deck experience telling me about the rigours of doing deck landings, especially in weather and at night. I think we all here have a good feel for what a challenging event this is and what a perishable skill it must be.
So now F-35 has Delta Path, which has been shown to make this event so much easier and, albeit with a small dataset of landings in reasonable conditions, appears to offer a high success rate. This has to be excellent news.
But, all systems fail. ALL systems CAN fail. So my question is this. If the F-35C force have a cadre of pilots who's normal landing mode is the relatively benign Delta Path approach and trap, how much time will they need to spend conducting traditional, manual landings in order to achieve and maintain proficiency in a failure mode?
So now F-35 has Delta Path, which has been shown to make this event so much easier and, albeit with a small dataset of landings in reasonable conditions, appears to offer a high success rate. This has to be excellent news.
But, all systems fail. ALL systems CAN fail. So my question is this. If the F-35C force have a cadre of pilots who's normal landing mode is the relatively benign Delta Path approach and trap, how much time will they need to spend conducting traditional, manual landings in order to achieve and maintain proficiency in a failure mode?
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Does not make sense. Firstly the FMS is very good by every account so that sim FCLP can be conducted in 'failure' or good mode. What exactly is a 'manual' landing in your estimation? The aircraft is computer controlled. There is no flap handle - the flaps (for the cats - recall 'cats 'n flaps'?) are on auto as is the throttle. There is no manual IMHO. OMG even the F-35B has auto eject in STOVL mode.
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Yes. This has been proven in 'live fire' tests where such things were replicated in labs. I think this demo has been mentioned elsewhere (also some work done specifically for the F-35B and LiftFan). I'll look for info - if required. There would be limits to what can be done - an advantage of computer control of flying qualities is this flexibility (perhaps demo'ed by the Israeli F-15 high speed landing with one stub wing after a mid-air?). This could not be done on a carrier however because there are weight/airspeed limits for the arresting gear (amongst other issues - including not an F-15).
No it isn't. The Saudis got FBW in the F-15SA. Otherwise the Eagle was designed with a pretty standard and simple mechanical control system coupled with electrical stick force sensors. Either system can fly the aircraft in the event of the other failing.
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As far as combat damage is concerned the FBW takes care of it to keep the aircraft controllable but this would of course only work up to a certain amount of damage. Most of the ideas used for the F-35 have been long proven on the F/A-18 through millions of flight hours including taking damage in combat. A good story comes from early testing on the F-117. An FSD aircraft on test lost one of it's vertical fins and the pilot had no idea until the chase aircraft told him with the FBW compensating automatically.
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Thanks 'dat581' must admit I lost interest in the F-15 + hook when I found out it was not carrier capable (or is it). Anyway I really had this mid-air in mind whilst the info is here: [F-35 LFT next post if anyone interested]
Pilots Thankful To Be Alive - Oceana Fliers Describe Collision, Landing Jets
April 25, 1996 WILLIAM H. MCMICHAEL Daily Press
Pilots Thankful To Be Alive - Daily Press
&
2 Oceana Jets Collide - Daily Press
Pilots Thankful To Be Alive - Oceana Fliers Describe Collision, Landing Jets
April 25, 1996 WILLIAM H. MCMICHAEL Daily Press
"...Anderson remained aloft in part because the flight control computers compensated for the jet's losses. Stephenson said F/A-18s are equipped with two mission computers, a redundancy he said is reflected elsewhere in the jet - in the two rudders and two engines, for example - to increase its chances of survival in the event of a collision or missile strike...."
&
2 Oceana Jets Collide - Daily Press
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Funny you should say that about the F-15. A navalised version was looked at due to the high cost and complexity of the F-14 but not proceeded with. Adding naval features such as the added structure and landing gear sent the weight rapidly higher. Adding more complex high lift devices to the wings didn't help either. By the end of the design process it weighed and cost almost as much as the Tomcat.
Spaz, re your message 224. Yes I agree the FMS is proving to be excellent and I do understand the use of flap - no flap switch because IDLC makes stick input control flap, changing approach angle rather than changing pitch, hence the name delta flight path.
My interest was about discussing the possibility of failure(s) that may degrade either FMS or any part of the system. I'm guessing your oblique reference to auto-eject in the B was a throw away line - barring a complete or catastrophic flight control failure, I'm hoping the reversion are mode isn't a Martin Baker let-down!
There's not much open source material on flight controls (probably a good thing), so I wondered if anyone had any unclassified gen to share on it.
Perhaps my question wasn't complete enough. Let's try, are there reversionary modes and, if so, is it a big deal for pilots to use it? My experience of flying FBW (a much older system than this!!!) leads me to conclude that failures can happen and when they do they can really change the way your aircraft flies.
My interest was about discussing the possibility of failure(s) that may degrade either FMS or any part of the system. I'm guessing your oblique reference to auto-eject in the B was a throw away line - barring a complete or catastrophic flight control failure, I'm hoping the reversion are mode isn't a Martin Baker let-down!
There's not much open source material on flight controls (probably a good thing), so I wondered if anyone had any unclassified gen to share on it.
Perhaps my question wasn't complete enough. Let's try, are there reversionary modes and, if so, is it a big deal for pilots to use it? My experience of flying FBW (a much older system than this!!!) leads me to conclude that failures can happen and when they do they can really change the way your aircraft flies.
Do a Hover - it avoids G
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CM
I have no personal experince of the latest mil FBW systems but those who do lead me to believe that they fail normal. In other words you just lose an element of redundancy.
Re the B's auto eject LM did not try and reinvent the wheel and went to the Forger people. There the system has never failed and been used some 30 times. The Forger trigger was attitude when in the hover mode (which rather limited airshows) dunno wot the B uses.
J
I have no personal experince of the latest mil FBW systems but those who do lead me to believe that they fail normal. In other words you just lose an element of redundancy.
Re the B's auto eject LM did not try and reinvent the wheel and went to the Forger people. There the system has never failed and been used some 30 times. The Forger trigger was attitude when in the hover mode (which rather limited airshows) dunno wot the B uses.
J
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John,
Perhaps I can help here. Your assumption on F-35 FBW fail modes is spot on.
Regarding auto eject, I remember that it was driven by the possibility of a catastrophic lift fan failure leading to very rapid nose down pitch to an attitude outside the seat envelope. I think that it's triggered by high pitch rates when the aircraft is in the powered lift mode, below certain speeds.
Best regards as ever to all those trying to keep the aircrew safe,
Engines
Perhaps I can help here. Your assumption on F-35 FBW fail modes is spot on.
Regarding auto eject, I remember that it was driven by the possibility of a catastrophic lift fan failure leading to very rapid nose down pitch to an attitude outside the seat envelope. I think that it's triggered by high pitch rates when the aircraft is in the powered lift mode, below certain speeds.
Best regards as ever to all those trying to keep the aircrew safe,
Engines
JF and Engines. Thank you. Good answers. I was going to pursue some more "what-ifs" that I had in mind, but it's all getting too diff! It's a bit like learning quantum physics during my degree course. Just accept that it is! Ta.
Do a Hover - it avoids G
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Previous posts on this thread - as I understand them - have indicated the X-35C had auto throttle and IDLC which carried over to the F-35C improved and improved again with 'Delta Flight Path' (aka 'Magic Carpet' for the Super Hornet). Here are the men at work - does not the old hook drop quick.
X-35C & F-35C FCLP & Arrests NIMITZ Nov 2014
X-35C & F-35C FCLP & Arrests NIMITZ Nov 2014
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An answer (seen in complete PDFs) for 'Mechta' above asking:
Aircraft Survivability Journal - Spring 2012 Issue Published by the Joint Aircraft Survivability Program Office
JSF FULL UP SYSTEM LEVEL TESTING F35 Flight Critical Systems Test By Chuck Frankenberger
http://www.bahdayton.com/surviac/asn...012_V9_web.pdf [no longer available there]
OR
http://www.f-16.net/forum/download/file.php?id=15817 (2Mb PDF)
&
AIRCRAFT SURVIVABILITY Journal - Spring 2014 Published by the Joint Aircraft Survivability Program Office
F135 PROPULSION SYSTEM LIVE FIRE TEST (LFT) by Charles Frankenberger
http://jaspo.csd.disa.mil/images/arc...014_spring.pdf (1.53Mb)
So what happens if you have battle damage which stops a control surface working? Will the automatic system adjust for this?
JSF FULL UP SYSTEM LEVEL TESTING F35 Flight Critical Systems Test By Chuck Frankenberger
"...CONCLUSIONS
The FUSL testing conducted on [F-35A first build] AA-1 was very successful meeting all defined test objectives and success criteria. Addressing synergistic effects, the electrical power and flight control systems successfully isolated failures and protected the redundancies built into these systems, allowing continued safe flight. The VSN architecture is robust, providing multiple paths to transfer data. Testing highlighted that fire is a significant threat to flight critical systems. The test team was able to verify that the actual ballistic damage response correlated very well to previous pilot in the loop simulator testing. Over the course of the test program, the LFT team witnessed firsthand the robustness of the F35 flight critical systems, no cheap system kills."
The FUSL testing conducted on [F-35A first build] AA-1 was very successful meeting all defined test objectives and success criteria. Addressing synergistic effects, the electrical power and flight control systems successfully isolated failures and protected the redundancies built into these systems, allowing continued safe flight. The VSN architecture is robust, providing multiple paths to transfer data. Testing highlighted that fire is a significant threat to flight critical systems. The test team was able to verify that the actual ballistic damage response correlated very well to previous pilot in the loop simulator testing. Over the course of the test program, the LFT team witnessed firsthand the robustness of the F35 flight critical systems, no cheap system kills."
OR
http://www.f-16.net/forum/download/file.php?id=15817 (2Mb PDF)
&
AIRCRAFT SURVIVABILITY Journal - Spring 2014 Published by the Joint Aircraft Survivability Program Office
F135 PROPULSION SYSTEM LIVE FIRE TEST (LFT) by Charles Frankenberger
"...CONCLUSIONS
Overall, the test results were favorable and in many cases the propulsion system performed better than predicted. Damage to blades and vanes in both the lift fan and main engine did not result in the catastrophic corn-cobbing often seen when gas path components are damaged. The control system is very capable in accommodating damage and providing information to the pilot. The data collected is being used to update assumptions and methodologies used in the vulnerability assessment. These updates will be available for the final F-35 aircraft assessment."
Overall, the test results were favorable and in many cases the propulsion system performed better than predicted. Damage to blades and vanes in both the lift fan and main engine did not result in the catastrophic corn-cobbing often seen when gas path components are damaged. The control system is very capable in accommodating damage and providing information to the pilot. The data collected is being used to update assumptions and methodologies used in the vulnerability assessment. These updates will be available for the final F-35 aircraft assessment."
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ONLY some woids from this excellent 6 page PDF article from Dec 2014 edition of Air International are excerpted below.
Cats, Traps & a Rooster Tail December 2014 Mark Ayton Air International
pp 42-47 Air International December 2014
Cats, Traps & a Rooster Tail December 2014 Mark Ayton Air International
"[F-35C Aircraft] “...CF-03/‘SD73’ and CF-05/‘SD75’...
...DEVELOPMENTAL TESTER TEST DIRECTOR
Cdr Shawn Kern is the Director of Test and Evaluation for F-35 Naval Variants and the senior military member within the F-35 Integrated Test Force (ITF) based at Patuxent River. He leads a diverse team comprising 920 members from the US Government, the military and contractors responsible for developmental test of the F-35B and F-35C aircraft during the System Development and Demonstration phase. During DT I, Cdr Kern led the F-35 ITF, provided government oversight of carrier suitability testing and co-ordinated with the USS Nimitz’s captain, executive officers and other F-35 stakeholders.
He told AIR International: “Launch testing included minimum catapult end speed determination as well as performance and handling during high and low energy catapult launches and crosswind conditions at representative aircraft gross weights. Approach and recovery testing focused on aircraft performance and handling qualities during off-nominal recoveries in low, medium, high and crosswind wind conditions. Data and analysis from DT I will support the development of initial aircraft launch and recovery bulletins for F-35C carrier operations and Naval Air Training and Operating Procedures Standardisation (NATOPS) flight manual procedures. Test results from DT I will also influence follow-on developmental and operational testing required to achieve F-35C initial operational capability.”
Lt Cdr Ted Dyckman is a US Navy F-35 test pilot assigned to VX-23 based at Naval Air Station Patuxent River, Maryland: he made the second-ever arrested landing on a super carrier in aircraft CF-05 on November 3 and the first night-time landing on November 13 in CF-03. Speaking about the F-35C’s performance around the carrier, Lt Cdr Dyckman told AIR International: “Everything met expectations and there were no surprises. Going through the burble was a big unknown, but the airplane responded better than we thought it would.
“We saw that the aircraft could trap: the only true bolter was a power call by the Landing Signals Officer when the aircraft touched down long with the hook down but came around and made an arrested landing.
“When the weather started to deteriorate we had such confidence in how the aircraft was flying that we lowered the weather minimums to those used by the fleet. I knew that when I lowered the hook I was going to trap. That says a lot for the airplane.
“Because the autopilots and flying qualities are so good, the workload to fly the jet is reduced and we were confident enough to declare it ready for night-time traps. It flew very well behind the ship and I made two hook-down passes and two traps. It’s unheard of to conduct night ops on a type’s first period at sea.
“We accomplished everything we set out to do, which allows us to go to DT II and conduct maximum speed catapult shots and carry internal and external stores and asymmetric payloads.”...
...Flight testing was split into three phases: day carrier qualification (CQ) and flight deck crew familiarisation; the development of aircraft launch bulletins (ALB) and aircraft recovery bulletins (ARB). In addition DT I also included Logistical Test and Evaluation (LT&E). Subsets of each phase comprised:
Aircraft Launch Bulletins
• Military rated thrust catapult launches
• Minimum catapult launch end speeds
• Low, medium and high excess wind over deck (WOD) catapult launches
• Crosswind catapult launches
• Bow and waist catapult launches
Aircraft Recovery Bulletins
• Approach handling qualities (AHQ) of F-35C approach modes: delta flight path, approach power compensator (APC), and manual
• Low, medium and high excess WOD recoveries
• Crosswind recoveries
• Bolter performance Logistical Test and Evaluation
• Deck handling including taxiing, towing and tie-down
• Weapons loading
• Basic maintenance, including aircraft jacking and landing gear servicing
• Maintenance support
Preparations
Since the author’s previous visit to the F-35 ITF at Pax River in April the main test objectives completed over the summer were arrested landings, touch and goes (a training evolution also known as field carrier landing practice or FCLP) and a structural survey of CF-03. The latter was a methodical check of the aircraft to ensure it was structurally suitable to be flown aboard an aircraft carrier. The survey included testing engineering fixes made to the aircraft’s pitch pivot pin and nose wheel steering motor. Although precautionary, the survey was required because functionality problems had been discovered with each component during the F-35C’s developmental flight test programme. A subset of the structural testing performed on CF-03, known as a shake, was also completed on CF-05 to ensure it was also suitable for carrier trials. No issues were found.
One other pre-deployment test evolution was electromagnetic environmental effects (E3). This required CF-03 to spend two weeks in the shielded hangar at Pax River, to ensure that electromagnetic interference from the ship’s emitters did not affect any of the aircraft’s vital systems and cause them to shut down. The official E3 test report was completed on October 16 which cleared the aircraft to embark onboard the carrier.
All requisite carrier suitability testing was concluded on October 17 and the final FCLPs were completed at Pax River four days later.
One interruption to the test programme over the summer was caused by the temporary grounding order resulting from an engine fire on F-35A AF-27, serial number 10-5015, at Eglin Air Force Base, Florida on June 23. Each engine underwent a rigorous inspection process and because of the priority given to DT I, CF-03 was the first to be inspected, analysed and cleared back to flight: CF-05 followed....
...No modifications were required to the flight deck, not even the Jet Blast Deflectors (JBDs): hydraulic-controlled panels designed to divert hot aircraft exhaust during launches. The panels are raised in preparation for takeoff, protecting the flight deck and aircraft behind from the hot aircraft exhaust. Modification of the JBDs will be required for subsequent DT evolutions, when afterburner will be required to launch aircraft with heavier all-up weights than those used during DT I. Any changes implemented will alter the cooling path of the F-35’s exhaust plume, which interacts with the carrier’s decking differently from that of the twin-engined members of the Hornet family....
...Support Onboard and from Ashore
DT I was supported by a pre-production, nonfleet representative version of the Autonomic Logistics Information System known as ALIS 1.03. According to the F-35 Joint Program Office: “Standard ALIS functions were in place and used to support F-35C operations and maintenance onboard USS Nimitz. The functions were accessible via approved Department of Defense network and cyber security policies and authorisations similar to ALIS support for F-35B STOVL deployments to the USS Wasp (LHD 1)....
...Increased robustness in the aircraft’s control laws refers to:
• Pro-rotation during a catapult and bolter.
• Integrated Direct Lift Control which integrates the control surfaces such that wing camber is altered to increase or decrease lift, thus allowing glide slope changes to be made without a large change in engine thrust.
• Delta Flight Path, which is an innovative leap in aircraft flight controls, that commands the aircraft to capture and maintain a glide slope. The system greatly reduces the pilot’s workload, increases the safety margins during carrier approaches and reduces touchdown dispersion.
Wind Effects
Aircraft carriers are unique in that they have different wind effects that the pilot and the aircraft’s flight control laws must take into account. The overall wind effect is called the burble,...
...“We are evaluating how the control law handles through the burble. Data collected during DT I will now be used by the control law engineers for analysis and to improve our simulator modelling. Because the burble is such a dynamic and integrated wind system there are challenges to modelling it accurately. Future F-35 pilot training will benefit from this work,” said Cdr Wilson....
...We started making intentional errors in our approaches [off-nominal]. This allowed us to see how the aircraft’s flight control laws react to corrections input by the pilot and the effect of the burble while trying to make the corrections. “The pilot intentionally lines up [on approach] on either side of the landing area…starting either high or low, or flying fast or slow to see if there is enough time to input the correction and get back on centreline, on glide slope and on speed [flying a proper approach speed] prior to touch down. “As we fly off nominal approaches, if the LSO [landing signals officer] doesn’t see a timely correction or doesn’t feel that the pilot is going to land safely, he or she will wave them off.
“The LSO [who is located on a platform positioned 120ft (36.6m) from the end of the ship and 40ft (12.2m) from the centreline on the port side] is a pilot trained to observe the aircraft as it flies down the approach watching for deviation in pitch attitude using a camera that shows whether the aircraft is on or off centreline. Listening to the aircraft, the LSO is trained to recognise changes in rates of vertical and horizontal movement to ensure the aircraft is going to clear the ramp at the aft of the ship and recover safely aboard. The LSO plays a vital role in the safe recovery of aircraft aboard the ship.
“Getting aircraft back to the boat is our first concern: our second is [preventing] what we call a long bolter. This occurs if the pilot fails to correct a big deviation and lands well beyond the four-wire [the last arrestment cable along the deck]. For safety purposes any time an aircraft touches down on the deck, the pilot needs sufficient deck to derotate, and get the throttle back to mil[itary] power to fly away. There’s not enough time for the plane to de-rotate with a long bolter, which means it could still have downward direction so when [the aircraft] rolls off the front end of the boat it’s going to sink....
...evaluated approaches with crosswinds behind the ship out to 7kts....
...“We also evaluated approach handling qualities in low and high wind conditions: low is 10 to 20kt, nominal is 20 to 30kt and high is in excess of 30kt. The team’s goal for DT I was to gain as much data with cross winds and various head winds to allow us to start writing our aircraft launch and recovery bulletins.”
What Next? Testing around the carrier gets more complicated with aircraft weight and asymmetry. On subsequent DT events the F-35 ITF will increase aircraft weight and asymmetry by loading stores on one side to create as much asymmetry as possible, which is the complicating factor. Cdr Wilson told AIR International that testing on subsequent DT events is going to look very similar but will evaluate heavier weights and asymmetric lateral weight differences.
OUTCOMES FROM DT I
• Flight test conducted in the operational environment.
• The F-35C demonstrated exceptional handling qualities throughout all launch and recovery conditions tested.
• All four test pilots rated the F-35C to be very easy to operate from the carrier. Arrested landings were consistent: the aircraft caught the optimal three-wire in the majority of the 102 traps. Pilot comments included: “I noticed the burble, but the aircraft just takes care of it”, “It makes flying the ball comfortable” and “This thing is a three-wire machine”....
......STATISTICS FROM DT I
Start date: November 3
Completion date: November 14
Flights: 33
Flight hours: 39.2
Catapult launches: 124
Touch-and-goes: 222
Arrested landings: 124
Bolters: 2 intentional with the hook down
Threshold test points completed: 100%”
...DEVELOPMENTAL TESTER TEST DIRECTOR
Cdr Shawn Kern is the Director of Test and Evaluation for F-35 Naval Variants and the senior military member within the F-35 Integrated Test Force (ITF) based at Patuxent River. He leads a diverse team comprising 920 members from the US Government, the military and contractors responsible for developmental test of the F-35B and F-35C aircraft during the System Development and Demonstration phase. During DT I, Cdr Kern led the F-35 ITF, provided government oversight of carrier suitability testing and co-ordinated with the USS Nimitz’s captain, executive officers and other F-35 stakeholders.
He told AIR International: “Launch testing included minimum catapult end speed determination as well as performance and handling during high and low energy catapult launches and crosswind conditions at representative aircraft gross weights. Approach and recovery testing focused on aircraft performance and handling qualities during off-nominal recoveries in low, medium, high and crosswind wind conditions. Data and analysis from DT I will support the development of initial aircraft launch and recovery bulletins for F-35C carrier operations and Naval Air Training and Operating Procedures Standardisation (NATOPS) flight manual procedures. Test results from DT I will also influence follow-on developmental and operational testing required to achieve F-35C initial operational capability.”
Lt Cdr Ted Dyckman is a US Navy F-35 test pilot assigned to VX-23 based at Naval Air Station Patuxent River, Maryland: he made the second-ever arrested landing on a super carrier in aircraft CF-05 on November 3 and the first night-time landing on November 13 in CF-03. Speaking about the F-35C’s performance around the carrier, Lt Cdr Dyckman told AIR International: “Everything met expectations and there were no surprises. Going through the burble was a big unknown, but the airplane responded better than we thought it would.
“We saw that the aircraft could trap: the only true bolter was a power call by the Landing Signals Officer when the aircraft touched down long with the hook down but came around and made an arrested landing.
“When the weather started to deteriorate we had such confidence in how the aircraft was flying that we lowered the weather minimums to those used by the fleet. I knew that when I lowered the hook I was going to trap. That says a lot for the airplane.
“Because the autopilots and flying qualities are so good, the workload to fly the jet is reduced and we were confident enough to declare it ready for night-time traps. It flew very well behind the ship and I made two hook-down passes and two traps. It’s unheard of to conduct night ops on a type’s first period at sea.
“We accomplished everything we set out to do, which allows us to go to DT II and conduct maximum speed catapult shots and carry internal and external stores and asymmetric payloads.”...
...Flight testing was split into three phases: day carrier qualification (CQ) and flight deck crew familiarisation; the development of aircraft launch bulletins (ALB) and aircraft recovery bulletins (ARB). In addition DT I also included Logistical Test and Evaluation (LT&E). Subsets of each phase comprised:
Aircraft Launch Bulletins
• Military rated thrust catapult launches
• Minimum catapult launch end speeds
• Low, medium and high excess wind over deck (WOD) catapult launches
• Crosswind catapult launches
• Bow and waist catapult launches
Aircraft Recovery Bulletins
• Approach handling qualities (AHQ) of F-35C approach modes: delta flight path, approach power compensator (APC), and manual
• Low, medium and high excess WOD recoveries
• Crosswind recoveries
• Bolter performance Logistical Test and Evaluation
• Deck handling including taxiing, towing and tie-down
• Weapons loading
• Basic maintenance, including aircraft jacking and landing gear servicing
• Maintenance support
Preparations
Since the author’s previous visit to the F-35 ITF at Pax River in April the main test objectives completed over the summer were arrested landings, touch and goes (a training evolution also known as field carrier landing practice or FCLP) and a structural survey of CF-03. The latter was a methodical check of the aircraft to ensure it was structurally suitable to be flown aboard an aircraft carrier. The survey included testing engineering fixes made to the aircraft’s pitch pivot pin and nose wheel steering motor. Although precautionary, the survey was required because functionality problems had been discovered with each component during the F-35C’s developmental flight test programme. A subset of the structural testing performed on CF-03, known as a shake, was also completed on CF-05 to ensure it was also suitable for carrier trials. No issues were found.
One other pre-deployment test evolution was electromagnetic environmental effects (E3). This required CF-03 to spend two weeks in the shielded hangar at Pax River, to ensure that electromagnetic interference from the ship’s emitters did not affect any of the aircraft’s vital systems and cause them to shut down. The official E3 test report was completed on October 16 which cleared the aircraft to embark onboard the carrier.
All requisite carrier suitability testing was concluded on October 17 and the final FCLPs were completed at Pax River four days later.
One interruption to the test programme over the summer was caused by the temporary grounding order resulting from an engine fire on F-35A AF-27, serial number 10-5015, at Eglin Air Force Base, Florida on June 23. Each engine underwent a rigorous inspection process and because of the priority given to DT I, CF-03 was the first to be inspected, analysed and cleared back to flight: CF-05 followed....
...No modifications were required to the flight deck, not even the Jet Blast Deflectors (JBDs): hydraulic-controlled panels designed to divert hot aircraft exhaust during launches. The panels are raised in preparation for takeoff, protecting the flight deck and aircraft behind from the hot aircraft exhaust. Modification of the JBDs will be required for subsequent DT evolutions, when afterburner will be required to launch aircraft with heavier all-up weights than those used during DT I. Any changes implemented will alter the cooling path of the F-35’s exhaust plume, which interacts with the carrier’s decking differently from that of the twin-engined members of the Hornet family....
...Support Onboard and from Ashore
DT I was supported by a pre-production, nonfleet representative version of the Autonomic Logistics Information System known as ALIS 1.03. According to the F-35 Joint Program Office: “Standard ALIS functions were in place and used to support F-35C operations and maintenance onboard USS Nimitz. The functions were accessible via approved Department of Defense network and cyber security policies and authorisations similar to ALIS support for F-35B STOVL deployments to the USS Wasp (LHD 1)....
...Increased robustness in the aircraft’s control laws refers to:
• Pro-rotation during a catapult and bolter.
• Integrated Direct Lift Control which integrates the control surfaces such that wing camber is altered to increase or decrease lift, thus allowing glide slope changes to be made without a large change in engine thrust.
• Delta Flight Path, which is an innovative leap in aircraft flight controls, that commands the aircraft to capture and maintain a glide slope. The system greatly reduces the pilot’s workload, increases the safety margins during carrier approaches and reduces touchdown dispersion.
Wind Effects
Aircraft carriers are unique in that they have different wind effects that the pilot and the aircraft’s flight control laws must take into account. The overall wind effect is called the burble,...
...“We are evaluating how the control law handles through the burble. Data collected during DT I will now be used by the control law engineers for analysis and to improve our simulator modelling. Because the burble is such a dynamic and integrated wind system there are challenges to modelling it accurately. Future F-35 pilot training will benefit from this work,” said Cdr Wilson....
...We started making intentional errors in our approaches [off-nominal]. This allowed us to see how the aircraft’s flight control laws react to corrections input by the pilot and the effect of the burble while trying to make the corrections. “The pilot intentionally lines up [on approach] on either side of the landing area…starting either high or low, or flying fast or slow to see if there is enough time to input the correction and get back on centreline, on glide slope and on speed [flying a proper approach speed] prior to touch down. “As we fly off nominal approaches, if the LSO [landing signals officer] doesn’t see a timely correction or doesn’t feel that the pilot is going to land safely, he or she will wave them off.
“The LSO [who is located on a platform positioned 120ft (36.6m) from the end of the ship and 40ft (12.2m) from the centreline on the port side] is a pilot trained to observe the aircraft as it flies down the approach watching for deviation in pitch attitude using a camera that shows whether the aircraft is on or off centreline. Listening to the aircraft, the LSO is trained to recognise changes in rates of vertical and horizontal movement to ensure the aircraft is going to clear the ramp at the aft of the ship and recover safely aboard. The LSO plays a vital role in the safe recovery of aircraft aboard the ship.
“Getting aircraft back to the boat is our first concern: our second is [preventing] what we call a long bolter. This occurs if the pilot fails to correct a big deviation and lands well beyond the four-wire [the last arrestment cable along the deck]. For safety purposes any time an aircraft touches down on the deck, the pilot needs sufficient deck to derotate, and get the throttle back to mil[itary] power to fly away. There’s not enough time for the plane to de-rotate with a long bolter, which means it could still have downward direction so when [the aircraft] rolls off the front end of the boat it’s going to sink....
...evaluated approaches with crosswinds behind the ship out to 7kts....
...“We also evaluated approach handling qualities in low and high wind conditions: low is 10 to 20kt, nominal is 20 to 30kt and high is in excess of 30kt. The team’s goal for DT I was to gain as much data with cross winds and various head winds to allow us to start writing our aircraft launch and recovery bulletins.”
What Next? Testing around the carrier gets more complicated with aircraft weight and asymmetry. On subsequent DT events the F-35 ITF will increase aircraft weight and asymmetry by loading stores on one side to create as much asymmetry as possible, which is the complicating factor. Cdr Wilson told AIR International that testing on subsequent DT events is going to look very similar but will evaluate heavier weights and asymmetric lateral weight differences.
OUTCOMES FROM DT I
• Flight test conducted in the operational environment.
• The F-35C demonstrated exceptional handling qualities throughout all launch and recovery conditions tested.
• All four test pilots rated the F-35C to be very easy to operate from the carrier. Arrested landings were consistent: the aircraft caught the optimal three-wire in the majority of the 102 traps. Pilot comments included: “I noticed the burble, but the aircraft just takes care of it”, “It makes flying the ball comfortable” and “This thing is a three-wire machine”....
......STATISTICS FROM DT I
Start date: November 3
Completion date: November 14
Flights: 33
Flight hours: 39.2
Catapult launches: 124
Touch-and-goes: 222
Arrested landings: 124
Bolters: 2 intentional with the hook down
Threshold test points completed: 100%”
Last edited by SpazSinbad; 27th Nov 2014 at 21:00. Reason: fmt wot else & spacs
Sorry to pick this up again. I may have completely misunderstood, but I got the impression that you guys were saying that the system fails "normal" and that a "manual" approach doesn't make sense...
Now you're quoting...
That looks like there are three modes, the last being stick and throttle - or "manual" in my estimation.
Originally Posted by Spaz
Does not make sense. Firstly the FMS is very good by every account so that sim FCLP can be conducted in 'failure' or good mode. What exactly is a 'manual' landing in your estimation? The aircraft is computer controlled.
Originally Posted by John
I have no personal experince of the latest mil FBW systems but those who do lead me to believe that they fail normal. In other words you just lose an element of redundancy.
Originally Posted by Engines
John,
Perhaps I can help here. Your assumption on F-35 FBW fail modes is spot on.
Perhaps I can help here. Your assumption on F-35 FBW fail modes is spot on.
F-35C approach modes: delta flight path, approach power compensator (APC), and manual