When Lockheed Martin rolls out the F-35C on July 28, US Navy pilots will be one step closer to operating a single-engine fighter off a carrier deck. The DEW Line contributor Dave Majumdar explores this issue with an active F/A-18 pilot with more than 1,700 flying hours, who asked to remain anonymous.
If there is any doubt that the US Navy aviation community will accept a single-engine fighter, such as the F-35C, one pilot has a clear answer: That "decision has been made" already and, after all, "the Navy is not a democracy".
But concerns about the issue among rank-and-file pilots clearly linger.
The F/A-18 pilot says the Navy has worked hard to get to a point where only twin-engine jets were serving on the decks of carriers.
In a single engine aircraft such as the Lockheed F-16, "a failure in
any engine component that leads to a loss of thrust or flame-out
equates to a quick attempt to try to troubleshoot the problem for a few
seconds before making the decision to eject. In a Hornet, by contrast,
even a total single engine failure can be ignored" if the situation
warrants it, the pilot says.
Ideally, he adds, in the event of an engine failure, "flight can easily be maintained at a safe altitude while carrying out emergency procedures".
When the tri-service Joint Strike Fighter programme was formed in the late 1990s, however, one area in which the Navy was forced to accept compromise was propulsion.
"The only way to meet the requirement was with one engine", says Steve Weatherspoon, Lockheed Martin's Deputy Test Verification officer for the F-35 Integrated Test Force.
Weatherspoon says the Lockheed-led team has worked hard to increase the reliability of the sub-systems surrounding the engine.
For example, the F-35's Integrated Power Package (IPP) provides constant backup power to the control systems, he noted. Similar redundancies are found throughout the aircraft he said, minimizing risks. Weatherspoon also points out that the reliability of single engine fighters has significantly improved in recent years while mishap rates have gone down.
But Lockheed must overcome perceptions of propulsion-induced mishaps accumulated and passed down among naval aviators since World War II. While single engine aircraft have come a long way with regard to reliability, on many occasions the loss of an engine is due to external causes.
During his early years flying with the Navy (piloting the F-14 Tomcat), for instance, the F/A-18 pilot described one particular incident. While aerial refueling the cover for the aircraft's probe broke off on contact with the "basket" and was ingested into an engine -- totally destroying the machinery. "Flames shot out from that engine", he says.
During another incident, he says he had witnessed a Hornet from his air wing land on a carrier with one engine shut down while the other engine, severely damaged, brought the stricken aircraft home. Upon launch from one of the catapults earlier, the aircraft had ingested foreign object debris into both engines. Only the twin-engine configuration had saved the aircraft from disaster, he says.
While the Hornet pilot was less than enthusiastic about the single engine configuration, other facets of the F-35C intrigued him. This was especially true of jet's stealth and sensors.
Ideally, he adds, in the event of an engine failure, "flight can easily be maintained at a safe altitude while carrying out emergency procedures".
When the tri-service Joint Strike Fighter programme was formed in the late 1990s, however, one area in which the Navy was forced to accept compromise was propulsion.
"The only way to meet the requirement was with one engine", says Steve Weatherspoon, Lockheed Martin's Deputy Test Verification officer for the F-35 Integrated Test Force.
Weatherspoon says the Lockheed-led team has worked hard to increase the reliability of the sub-systems surrounding the engine.
For example, the F-35's Integrated Power Package (IPP) provides constant backup power to the control systems, he noted. Similar redundancies are found throughout the aircraft he said, minimizing risks. Weatherspoon also points out that the reliability of single engine fighters has significantly improved in recent years while mishap rates have gone down.
But Lockheed must overcome perceptions of propulsion-induced mishaps accumulated and passed down among naval aviators since World War II. While single engine aircraft have come a long way with regard to reliability, on many occasions the loss of an engine is due to external causes.
During his early years flying with the Navy (piloting the F-14 Tomcat), for instance, the F/A-18 pilot described one particular incident. While aerial refueling the cover for the aircraft's probe broke off on contact with the "basket" and was ingested into an engine -- totally destroying the machinery. "Flames shot out from that engine", he says.
During another incident, he says he had witnessed a Hornet from his air wing land on a carrier with one engine shut down while the other engine, severely damaged, brought the stricken aircraft home. Upon launch from one of the catapults earlier, the aircraft had ingested foreign object debris into both engines. Only the twin-engine configuration had saved the aircraft from disaster, he says.
While the Hornet pilot was less than enthusiastic about the single engine configuration, other facets of the F-35C intrigued him. This was especially true of jet's stealth and sensors.
on July 27, 2009 9:47 PM | Reply
That "decision has been made" already and, after all, "the Navy is not a democracy".
The answer I would expect from a Naval Officer. He might disagree with the decision, but he'll make it work. REFRESHING!
on July 27, 2009 10:34 PM | Reply
Man has reached the best ever carrier flight safety record for fighters with the Super Hornet ( it takes out a few remaining flight profile nasties in the very safe legacy Hornet )
What does man do?
Re-introduces the hazard to the carrier deck.
After the F-35C goes way over its price point, if it ever passes OPEVAL, the Navy will only be able to afford to have one F-35C squadron deployed on a carrier.
Another gold plated drain on the Navy that still has to pay for gold plated decisions on the purchase of big grey floaty things.
on July 28, 2009 12:39 AM | Reply
The F-35C makes me extremely nervous. There should be no such thing as a single engined naval aircraft. Anyone who reads Approach magazine should be very nervous as well - there are many articles about precautionary in-flight shutdowns, and actual engine and accessories failures in flight. Is there a repository of engine failure / precautionary shutdown cases? I'd be curious to see how many are logged each year.
on July 28, 2009 2:05 PM | Reply
The A-7E was retired after the first Gulf War. It was a medium wt single engine attack fighter. The A-4 was used by USMC and Navy off of carrier decks. It performed well and was single engine. The institutional memory of certain members on this page is lacking to ignore those two relatively recent examples of single engine airplanes performing well.
on July 28, 2009 3:23 PM | Reply
It is better for a real pilot to fly with one engine, than a UAV with a pimple face "flying" it from a console from somewere in the states.
Better to be happy with one.
on July 28, 2009 6:26 PM | Reply
Hmm I wonder what Eric "Winkle" Brown would have to say about the single engine controversy!!
on July 28, 2009 8:12 PM | Reply
As any good reliability engineer will tell you, having two engines mainly doubles the odds of encountering an engine problem. Institutional memory in the Navy might be a little misdirected, too. Having two engines in the TF-30 powered F-14 may have saved some aircraft when engine problems were all-too-frequently encountered, but that's kind of like arguing that the box of spare parts supplied with a new Lada is a bonus feature.
on July 28, 2009 9:22 PM | Reply
"The A-7E was retired after the first Gulf War. It was a medium wt single engine attack fighter. The A-4 was used by USMC and Navy off of carrier decks. It performed well and was single engine. The institutional memory of certain members on this page is lacking to ignore those two relatively recent examples of single engine airplanes performing well."
Nice try with the spin. A two engine fighter the F/A-18 was made to replace those platforms. Part of that was the want of a two engine jet for safety. Duh.
While you are at it with you "institutional memory", try remembering what the Navy asked for in their input to what a JSF should have-Two aircrew, Two engines and 1000 mile radius.
Scoring that gives us 2 points for the Super Hornet and zero points for the F-35.
on July 28, 2009 10:11 PM | Reply
Very well said Richard and Atomic Walrus!
on July 28, 2009 10:45 PM | Reply
Would the same reliability engineer state that having two magnetos basically doubles the chance that one would fail?
on July 29, 2009 2:00 AM | Reply
OK ELP, if you won't go with institutional memory how about procurement history. The Navy had just failed in its bid to have the A-12 come online. Now what does two seats and a 1000 mile range sound like? If your answer was anything but an A-12 surrogate then you're not being honest. The historical fact is this. The Navy failed when they did not proceed with the A-6F concept and have been paying a price since then. They initially embarked on the all stealth course that the AF adopted, thought better of it and lost the ability to get an aircraft that would be serving admirably today (A-6F). The F-35 is the next best thing to the magical A-12 in today's budgetary environment. DEAL WITH IT.
on July 29, 2009 10:02 PM | Reply
"Would the same reliability engineer state that having two magnetos basically doubles the chance that one would fail?"
You bet - magnetos have a given failure rate per unit time, so two magnetos doubles your chance of encountering a failure. Of course, there's also a difference between redundant systems (primary and back-up) and so-called redundancy like having two engines. That second engine isn't really a redundant system, since twin-engined aircraft aren't designed to obtain 100% power off a single engine. At best you've got degraded but acceptable function after one of the engines fails.
on July 30, 2009 1:16 AM | Reply
In effect, however, having 2 engines, 2 mags, 2 vaucum pumps, multiple electrical busses, hydraulic and control channels, flight computers, etc. all contribute to increased survivability through some degree of redundancy. Incidentally, the AF replaced the A-7 with the A-10 - a twin engined plane - using redundancy as one of the ways to increase survivability. Redundancy is good even though you theoretically increase the probability of failure. Couple that with the maritime operating environment...
on July 30, 2009 11:14 AM | Reply
Try going back to the math books. For a given probability of an independent failure the probability of the same failure simultaneously occurring in a duplicate part is the square of the original probability. For a double engine failure you're looking at a common failure mode (running out of fuel, big AA shell going bang between them, etc) or combined mode (failed fan blade cuts through into the second engine) the number of engines is irrelevant - you've got 0% thrust no matter what. But there's plenty of single engine failure modes, and I'd bet that every navy crewman would much prefer that when that when the FADEC fries on engine #1 or it swallows a pelican that they've still got at least 40% of the installed thrust still available 'cos there's a second engine, rather than that big fat zero.
on July 30, 2009 5:29 PM | Reply
Retrograde engine box score for 2 cruises with single engine birds
Cruise 1
J52 - 48 one A-6 Sqdn and EA-6B det embarked, 36 installed engines
TF41- 5 Two A-7 Sqdn's 28 installed engines
TF30 57 Two F-14 Sqdn's 48 installed engines
Cruise 2
J52 - 53
TF41 - 7
TF-30 -55
Don't forget, some engine were repaired and returned to Sqdn, other were canned and sent off. These numbers include processing, uncanning, repairs ,etc.
Cruise 3 All twin engine aircraft,
I stopped counting by type, we pumped out 178 engines over the work-ups and cruise.
Cruise 4 All Twin Engine Aircraft
I didn' keep a good count by type, but it was about 85 engines of all types. J52, T56, T700, TF34, Etc.
F404, I forget how many engines, but 98 modules were processed. Assuming two per engine, thats still 45 engines for the cruise. Thats pretty much right up there with the TF30, ain't it boys? Granted, repair time was only about 25% of that for the TF30.
on July 30, 2009 11:46 PM | Reply
Geez, this question is as old as the program. There's always somebody who'll be unhappy with the answer.
Who among us think that the tradeoff of 1 vs 2 engine for the JSF wasn't examined up and down, forward and back, AND inside and out? And all as part of a total survivability and mission reliability per some unit of cost (including maintenace and losses to accidents)?
If you don't believe the program didn't to the homework and math, WHY do you believe it wasn't done?
If you DO believe it was done, but (the ubiquitous) 'they' got the answer "wrong", why do you believe YOU are "right"?
on July 31, 2009 1:18 AM | Reply
Well,all I can say about single eng vs two is from an old time Navy R4D, P2V, P5M crew member with 1048 flt hrs logged..it is so good to have that other engine when one fails and it occured a bunch of times out over water in my Naval Aviation career in the Navy and I made it home each time and thankful for 2 vrs 1 engine...
on August 4, 2009 10:14 PM | Reply
Real-world data refutes the two-engines-is-safer argument. The loss rates for F-16s (single-engine) and F/A-18s (dual-engine) are essentially identical, with one experiencing slightly more or fewer losses than the other year over year. While the differences are statistically almost meaningless, the single-engine F-16 (3.9 Class A accidents per 100K flight hours) actually has a better safety record than the twin-engine F/A-18 (4.2 Class A accidents per 100K flight hours).
on August 4, 2009 10:55 PM | Reply
I'm curious how many precautionary shut downs are executed per 100K flight hours in F/A-18's, EA-6B's, etc.