What Caused Lynyrd Skynyrd's Plane to Crash? originally appeared on Quora - the knowledge sharing network where compelling questions are answered by people with unique insights.
Answer by Tom Farrier, Retired USAF command pilot; Chair, ISASI Unmanned Aircraft Systems Working Group, on Quora.
Be warned: I read this as you asking an expert in accident investigation for an analysis, so I'm going to get into eye-glazing detail accompanied by a certain amount of conjecture. If you're idly curious, the first few paragraphs below should do you fine. On the other hand, if you really want to understand what's known to have happened and what might have led to what was officially determined, I'm here to help. Get comfortable.
Wikipedia and other popular sites often seem like good places to start to answer questions like this, but in my specialty I prefer to go to the source. In this case, it's the National Transportation Safety Board's investigation report AAR 78-06, which you can download in its entirety at
The crash itself took place on October 20, 1977. The type of aircraft involved in the accident was a chartered, 30 year-old Convair 240, owned and operated by L & J Company. Of the 26 crew and passengers aboard, both pilots and four passengers were killed, and the 20 survivors all were injured to varying degrees. The aircraft itself was chock-full of people -- it was configured for 24 passengers, and that's what it was carrying. (The original airliner's cabin was designed to carry up to 40 passengers, but this charter aircraft was equipped with tables and couches that cut into that number pretty significantly.)
As far as what caused the crash itself, the investigators concluded the following:
"The National Transportation Safety Board determines that the probable cause of this accident was fuel exhaustion and total loss of power from both engines due to crew inattention to fuel supply. Contributing to the fuel exhaustion were inadequate flight planning and an engine malfunction of undetermined nature in the right engine which resulted in higher-than-normal fuel consumption."
In the body of the report, the NTSB clarified that the engine malfunction itself most likely wasn't that big a deal: "Although examination of the engine and its components did not identify the exact discrepancy. the Safety Board believes that the discrepancy was of a general nature, such as an ignition or induction problem, and was not a major mechanical failure." So, bottom line: the plane ran out of gas and crashed.
Okay -- those are the unvarnished, bare-bones words from those responsible for making the determination. The fact that there wasn't much, if any fuel aboard is evident from the lack of a post-crash fire. Before the crash, the crew called air traffic controllers to request a divert to a nearby airport, stating they were "low on fuel." The fact that a pretty big aircraft balled up while attempting a forced landing at twilight isn't all that surprising.
Perhaps a little more thinking and digging might be in order, first to zero in a little more on the "why," and then perhaps to a certain extent to consider the "WTF" of how the crew got themselves in this situation in the first place.
A number of years ago, once I started getting interested in aviation safety in an organized way rather than just as a matter of self-preservation, it started becoming pretty obvious to me that a lot of popular entertainers, illustrious sports figures, powerful politicians and other celebrities have died in plane crashes over time.
Consider: High-profile performers like Patsy Cline, Richie Valens, Buddy Holly and Jiles Richardson (the "Big Bopper"), Jim Croce, Ricky Nelson, Aaliyah, Ronnie Van Zant and Steve Gaines, Audie Murphy, Stevie Ray Vaughan, Jenni Rivera, Soundarya, and most of Reba McEntire's band all died in non-scheduled aircraft crashes. Whole sports teams and NASCAR crews have been decimated in such events, as well as individual standouts like Roberto Clemente. Hale Boggs, Nick Begich, Mickey Leland and Ted Stevens -- all current or retired members of Congress -- died under similar circumstances, as did sitting Secretary of Commerce Ron Brown (in a dedicated VIP airlift aircraft).
(If you'd like to see a much longer and more depressing set of lists of this type, check out Wikipedia's List of fatalities from aviation accidents and "Plane Crash Info" (Image)).
Aircraft accidents were hardly unusual events during the first half of what has come to be referred to as "The Century of Flight" -- the 100 years starting with the Wright Brothers' first flight in December of 1903. However, it's somewhat astonishing to note how often luminaries like those on the list above died in non-scheduled operations that they themselves were not flying.
Keep this observation in mind as you read on. I personally think there's a common thread among them that might apply to the accident asked about in this question as well. I'll come back to it presently.
Okay. Having offered up the above framing thoughts regarding aviation-related death among the influential, let's get into the specifics of the Lynyrd Skynyrd accident itself.
The aircraft involved was refueled two days before the accident, upon its arrival at Greenville SC, with 400 gallons of the appropriate type of fuel. There's no record as to how much was aboard when they filled up that I can find; the NTSB investigators did their best to make such a calculation, to no avail. However, according to their report, "Normal average fuel consumption for the Convair 240 aircraft powered with the Pratt and Whitney R2800CB-16 engine is about 183 gallons per hour." That's a useful data point in and of itself.
When the crew filed their flight plan on the day of the accident, they planned for 2 hours and 45 minutes of flight (2+45) to travel the roughly 550-600 nautical miles between Greenville and Baton Rouge, with five hours of fuel aboard (5+00). (Their route of flight works out to roughly 580 nautical miles from takeoff to landing.)
Five hours of fuel at the standard burn rate listed above works out to perhaps 1,000 gallons of gas aboard (the NTSB report suggested 900), and a flight of less than three hours should have used perhaps 600 gallons, tops; it seems likely they would have expected to need less than 550 gallons. On the basis of what they put on their flight plan, fuel shouldn't have been an issue, but the 400 gallons they added definitely didn't top them off; otherwise, they would have listed at least 7+30 to 8+00 endurance (1,550 gallon fuel capacity per the NTSB report).
So, they weren't by any means full of fuel, but they presumably were carrying significantly more than just the 400 gallons they bought on October 18th. Thatamount by itself would have taken them about 2+10 if the tanks had been totally dry when they fueled up, assuming the engines were operating optimally. (Hold that thought.)
According to the NTSB report, the plane took off at 4:02 PM Central Daylight Time. (I found this a little confusing at first since South Carolina is on Eastern time, but a footnote states that all times in the report were rendered in Central time.) Two hours and forty minutes into a planned 2+45 flight -- at 6:42 PM -- they weren't anywhere near Baton Rouge yet, but they had run dry. Huh?
The NTSB report specifically states that a normally operating aircraft of this type, having flown the time it had prior to impact, should have had about 207 gallons of fuel aboard if it had started out with what they stated on their flight plan. The investigators found the wreckage had about a quart of fuel in it. The Board ruled out any possibility of a fuel leak or the aircraft having been fueled with less than what supposedly had been provided at prior fuel stops. As far as the improperly functioning engine was concerned, the investigators concluded that running it on "auto-rich" the entire flight should've burned a maximum of perhaps 70 gallons over and above normal consumption.
It appears the aircraft had only flown perhaps 85 to 90% of their intended route of flight when the pilots realized they were basically out of gas, and they took 2+40 just to cover that distance; they probably would have needed at least another 20 minutes or so to get from where they were to Baton Rouge (BTR) when they made the decision to reverse course and try to make McComb (MCB).
According to the accident report, there weren't any headwinds getting in their way at all -- just a pretty benign amount of crosswind from the northwest that would have required a relatively minor amount of correction. The Convair 240's advertised cruise speed is about 250 knots, and their ground speed shouldn't have been much different from that based on winds aloft.
So, their flight plan's time was so far off that it almost seems like they had no real idea how long it would actually take them, or something was seriously slowing them down along their entire route of flight. On the surface at least, it also seems like they never even looked at their fuel gauges throughout the flight.
Even given the above ambiguities and unexplained conditions, on page 14 of the report, the NTSB gets pretty blunt:
"The crew was either negligent or ignorant of the increased fuel consumption because they failed to monitor adequately the engine instruments for fuel flow and fuel quantity. Had they properly monitored their fuel supply and noted excessive fuel consumption early in the flight , they could have planned an alternate refueling stop rather than attempting to continue flight with minimum fuel."
Bam.
The NTSB has a fairly narrow approach to conducting its investigations and determining causes when it chooses to hew to the most rigorous interpretation of its charter. It only was about two years into its newly legislated "independent safety board" status when this accident occurred. Although its perspective has gotten a little more nuanced over time, its institutional mindset typically has been to identify a failure on the part of some identifiable party, and then to stop there. I don't fault them for this (because at least in this case the crew's failure to catch the dwindling fuel state really is pretty stunning), but the Board tends to stop asking "Why?" at a certain point. I'm inclined to want to think a few steps farther.
Was the crew somehow impaired? Nope. The report states, "Toxicological examination of the flightcrew disclosed no evidence of drugs, alcohol, or elevated levels of carbon monoxide in the blood." Still, for whatever reason, they flew an aircraft with X amount of fuel aboard for one heck of a lot longer than you would expect a qualified pair of pilots to tolerate, assuming they were aware of their situation. Since pilots tend to be rather cognizant of the fact that they'll be first to arrive at the crash scene if they let things get out of hand, I have a crawly feeling that something else was in play here.
Was the aircraft overloaded? A Convair 240 could legally take off weighing just shy of 42,000 pounds, with a typical empty (no fuel) weight of about 27,600 pounds. Its advertised payload was either a full passenger load or 9,350 pounds of cargo. (Convair 240/340/440/540/580/600/640/5800 | Airliners.net).
Now let's start cutting into the margins. A full load of fuel would have weighed at least 9,000 pounds all by itself; the reported 5 hours' worth that their flight plan claimed would have run perhaps 6,000 pounds. Standard passenger weights in effect at the time, plus assumed luggage per passenger, would have added 4,440 pounds to it.
Just the lesser amount of fuel, passengers and baggage would have brought the aircraft up to less than 5,000 pounds below its maximum gross weight, and a full fuel load would have left them with less than a ton of cargo-carrying wiggle-room beyond that. It seems reasonable to assume that at least some touring equipment (instruments, speakers, lighting, etc.) was aboard, but it isn't mentioned in the report. Hmm.
The biggest hazards associated with overloading an aircraft are in not recognizing that you've done so, or doing so because you can (or perceive you need to). Here's what Skybrary (AP4ATCO - Weight and Balance) has to say on this subject:
"Most modern aircraft are so designed that if all seats are occupied, all baggage allowed by the baggage compartment structure is carried, and all of the fuel tanks are full, the aircraft will be grossly overloaded. This type of design gives the pilot a great deal of latitude in loading the aircraft for a particular flight. If maximum range is required, occupants or baggage must be left behind, or if the maximum load must be carried, the range, dictated by the amount of fuel on board, must be reduced."
Based on the numbers set forth above, along with the possibility that the crew might have had a need to try to accommodate a lot of bodies and gear, I'm hesitant to say "no" to the possibility of overloading, especially since a heavier aircraft is a thirstier aircraft. By the same token, the NTSB report explicitly discounts this possibility (as well as that of crew incapacitation) in the first two paragraphs of its analysis:
"The flightcrew was properly certificated and trained in accordance with applicable regulations. There was no evidence of preexisting medical problems that might have affected the flightcrew's performance.
"The aircraft was certificated and equipped according to applicable regulations. The gross weight and [center of gravity] were within prescribed limits. The aircraft's structure and components were not factors in this accident. There was no evidence of any malfunction of the aircraft or its control system. The propulsion system was operating and was producing power until fuel was exhausted."
The historical record shows only a bare handful of explicit fuel exhaustion accidents involving this family of aircraft in civilian operation over time. Most unequivocally, a Swissair flight from Geneva to London crashed into the English Channel in 1954, an accident placed squarely on the pilots for running themselves out of gas; this is summarized at ASN Aircraft accident Convair CV-240-4 HB-IRW Folkestone.
(Beyond that one, I'm personally suspicious about a 1960 accident involving a flight from Frankfurt, Germany to Rimini Italy as well (ASN Aircraft accident Convair CV-240-4 D-BELU Rimini Airport (RMI)) -- its listed cause is, "The failure of the aircraft's left engine followed by the malfunction of the right engine," which makes me twitch a bit.)
(NOTE: In a weird coincidence, the distance between departure and arrival airports in both of the above accidents was just under 500 nautical miles, and the Lynyrd Skynyrd aircraft wasn't going all that much farther than that; no obvious correlation to me, but maybe CV-240 drivers might know of some -ism of the aircraft that might make that significant somehow.)
Still, there's no apparent history of this family of aircraft ever having a pattern of accidents due to fuel exhaustion or excessive consumption, period. This includes the U.S. military variants -- designated T-29 and C-131 -- which had reasonably safe operating histories and no fuel exhaustion accidents that I could find. So, let's accept the proposition that the NTSB report leaves us with -- a flyable aircraft, responsibly loaded and not stuffed to the gills with excess trappings and hangers-on of a touring band, was flown until it ran out of gas.
Maybe it was simple pilot inattention and/or negligence that killed these people. Then again, maybe there was another factor in play that's been around for a long time that caused corners to be cut, or perhaps put undue pressure on the crew to push things too far from a weight management and range perspective.
Let's circle back to the observations I made earlier regarding the loss of the powerful and influential in aircraft accidents. In my youth I did a fair amount of VIP flying. These are not easy passengers to please. They will push you; they will challenge you. Whether in a military flight or an aircraft leased for the purpose, they want to get where they want to be, when they want to be there. Little irrelevancies like weather, aircraft condition, or their desire to drag along unplanned-for people or "stuff" don't matter to them.
The Lynyrd Skynyrd accident report accident report includes a curious line of discussion regarding the status and terms of the leasing agreement between the band's management and the charter operator. It also goes to some pains to highlight the timeline associated with the official mail submission of the signed leasing agreement to the FAA. The legal nuances here are a bit outside my usual swim lane, but I couldn't help but be struck by the following passage:
"It therefore appears to the Safety Board that whether this lease was or was not adequate is not the primary safety problem, but how does the system in such a case protect a lessee who is uninformed either by design, by inadvertence, or by his own carelessness... In November 1977, FAA amended CFR 91.54 to require that lessees notify the nearest FAA office 48 hours prior to the first flight under a lease and provide information concerning (1) the departure airport, (2) time of departure, and (3) the registration number of the aircraft. In adopting the amendment, the FAA stated that the purpose of the new requirement was to give the FAA notice prior to the flight and thereby an opportunity to conduct preflight surveillance of lease and contract operations. This requirement should serve to protect innocent lessees if... the FAA office takes action to assure that there is a clear understanding by the lessee as to who is the operator and what responsibilities and obligations are thereby assumed."
An FAA "advisory circular" (AC 91-37A) was updated a few months after the Lynyrd Skynyrd accident. It includes the following passage:
"There have been instances wherein users of charter aircraft became the victims of certain operators. Illegal and unsafe operations have occurred which have developed into tragedies. A study of air charter operations was conducted and a report written which, among other things, recommended increasing the safety of operations involving U.S.-registered large civil aircraft that are being operated under a lease or contract of conditional sale arrangement.
"a. The report indicates that in many instances lessees and conditional buyers of aircraft did not realize that they were legally responsible for operational control of the aircraft as defined in Part 1 of the Federal Aviation Regulations (FARs). In other cases, the report indicates that even if the lessee or conditional buyer did realize it, very few recognized their responsibilities for compliance with the FARs.
"b. The report also indicates that a number of owners of large airplanes have evaded compliance with the applicable certification and operating rules of FAR Part 121 governing air carriers and commercial operators, through the use of devious leases and conditional sales contracts. This evasion of compliance made it appear that the lessees and conditional buyers were responsible for operational control, when in fact they did not have that responsibility. This knowing or unknowing assumption of responsibility creates a serious problem in air safety and may involve legal liabilities."
If you look at the above one way, you might get the impression that the aircraft's owner -- the L&J Company -- wanted to push off responsibility for anything bad that happened while the band had their aircraft under the lease onto the band itself. From another angle, it suggests that they were being pushed to provide services that their aircraft couldn't handle, and wanted it clearly on the record that if their pilots were pushed into trying to carry too much, it was the lessee's fault and not theirs.
I honestly don't care either way. I'm kind of appalled that this kind of ambiguity even existed in aviation regulations of that era. These days, if you're flying this kind of operation for compensation or hire, it can't be conducted under "general flight rules" at all -- it's governed by 14 CFR Part 135 as a minimum. The question of who's responsible for the safety and regulatory compliance of the leased operation is simple: the certificate holder has operational control, period.
Here's where I have to return to the hit parade of public figures who died in aircraft accidents mentioned early in my response. These were for the most part people used to getting their way, or perhaps were surrounded by people who would be jerks on their behalf. A depressing number of the accidents in which they perished involved dodgy weather or other factors -- like overloading -- that were duly laid at the feet of the pilots in the investigation reports. I also note the periodic involvement of fairly young/inexperienced pilots in such narratives... the kinds who can be pushed into doing things that defy good judgment or common sense.
I've been subjected to pressure to get somebody somewhere right now more than once in the course of my flying career. Fortunately, I've always been hard-headed enough to want to save my own skin, and I've also had excellent backing from my chain of command when a given power broker has gotten testy about a delay, cancellation or re-routing. By the same token, I've never been put in the position of getting pressure from a paying customer to stick my neck out, and I've never been in a situation where rules that should be clear instead are nebulous.
Nobody has ever come forward saying the Lynyrd Skynyrd crew was pressed in any way, at least as far as my research has uncovered. There was no cockpit voice recorder on the accident aircraft, so there's no way of knowing if they were getting distracted, pushed or needled once they were airborne. Still, something doesn't add up:
- The aircraft didn't fly anywhere near as far as it should have been able to go if it had the fuel load listed on its flight plan.
- The aircraft only flew about a half-hour farther than it could have flown if the only fuel aboard was what they took on after arriving at Greenville.
- The aircraft didn't make anywhere near the ground speed it should have made along its route of flight.
- The crew doesn't seem to have been minding the store and flew past countless airports they could have plunked down into to top off en route to Baton Rouge.
So, what caused the plane to crash? Running out of gas.
Why did it run out of gas? That's the $64,000 question, and likely is the one that'll never be answered.
I just hope we don't continue to read about stuff like this in the deaths of present-day celebrities, but the wheel keeps turning. The cause of the Mexican crash that killed banda singer Jenni Rivera in December of 2012 could not be officially determined following investigation by the Dirección de Aeronáutica Civil de México. However, it featured a 78 year-old owner/operator flying a 43 year-old aircraft in reportedly dubious condition, with a 21 year-old co-pilot allegedly not licensed to fly outside the U.S.
Rivera and her entourage finished a performance in Monterrey, Nuevo Leon well after midnight, held a press conference at the concert venue, and took off at 3:00 AM local headed toward Toluca, outside Mexico City. This was reportedly a last-minute decision made by Rivera, who wanted to leave town instead of spending the night in Monterrey. (10 revelaciones)
So, from the heart:
Please, famous people -- don't push your pilots. Yeah, the aircraft and its convenience are yours to command, but accommodating you might turn out badly.