Wednesday, April 16, 2014

No Chutes

Debris from a USAF KC-135 that crashed in Kyrgyzstan last May.  The accident destroyed the aircraft, based at McConnell AFB, Kansas and claimed the lives of three airmen from Fairchild AFB, Washington (AP photo via Fox News) 

Eleven months ago, an Air Force KC-135 tanker crashed shortly after takeoff from Manas, Kyrgyzstan, killing the three crew members onboard.  The accident was blamed on a faulty flight control system and limited pilot experience.  Investigators determined that control system problems caused the Stratotanker to continuously "Dutch roll," pitching back and forth as increased yaw creates more lift on one wing than the other.  The roll continues until increased drag pulls the wing back to a neutral position, then is repeated on the other. 

In most cases, this type of problem can be corrected by shutting down the flight control system and using the jet's ailerons to regain stable flight.  Instead, the crew of the doomed tanker, callsign Shell 77, kept using their rudder--and inputs on the flight control system.  That made the rolling even worse; finally, the prolonged rolling caused the KC-135's tail to snap off, sending the tanker into steep dive towards the earth.  The Air Force accident investigation board also concluded that the aircraft--with 175,000 pounds of fuel on board--exploded before it hit the ground. 

There was one more factor that sealed the crew's fate.  As detailed in the current issue of Time,  reports, there were no parachutes aboard the tanker.  They were removed from the KC-135 fleet in 2008 as a cost-saving measure.  Defense reporter Mark Thompson included a quote from the Air Force news article that announced their elimination:

"By design, parachutes slow things down. Crew members forced to evacuate in-flight aircraft with parachutes, for example, have much gentler impacts with the ground than those without chutes. But the only thing being slowed by parachutes aboard KC-135 Stratotankers, Air Force leaders recently decided, was the mission. So they got rid of them. Removing parachutes from military aircraft may sound peculiar, but KC-135s are not like other aircraft. They seldom have mishaps, and the likelihood a KC-135 crew member would ever need to use a parachute is extremely low."

That may sound heartless, but there is a certain amount of logic behind that decision.  The KC-135 has an excellent safety record, and the number of controlled bail-outs from that platform is infinitely small.  To his credit, Mr. Thompson managed to track down a former navigator, Joseph Heywood, who parachuted from his tanker--45 years ago.  In that instance, the KC-135 was running out of fuel and the instructor pilot at the controls ordered the other crew members to prepare for bail out.  With the engines out and the jet (apparently) moments from a crash, Heywood and three other crew members hit the silk.  The IP managed to land the jet at K.I. Sawyer AFB on Michigan's upper peninsula. 

"I'd rather have a small chance than no chance at all," Mr. Heywood told Time.

But that raises a salient question: how much of a chance did the crew of Shell 77 really have?  The aircraft commander, Captain Mark Voss and his co-pilot, Captain Victoria Pickney, were fighting to control the KC-135.  Their boom operator, Technical Sergeant Herman Mackey III, played no role in flying the aircraft, but he was probably busy trying to secure any loose equipment in the cockpit or cargo compartment.  In other words, the crew was very much engaged in trying to save the aircraft and likely continued those efforts until they lost consciousness.  Even if parachutes had been available, it's hard to say if the crew would have decided to jump--or had enough time to escape from the aircraft.  

That's because the process of leaving the aircraft involves more than just strapping on a chute, opening the crew door and jumping out.  The last bit of flight data information from Shell 77 indicated the tanker was at 20,000 feet.  At that altitude, you'll need oxygen.  There's a bottle in your parachute pack, but you need to connect it to your helmet's oxygen tube and face mask before bailout. 

And, did we mention that KC-135 crews stow their helmets during the mission, since they're typically not required in a pressurized aircraft that doesn't perform acrobatic or violent maneuvers?  Under those circumstances, crew members would need a few moments to don their helmets and chute packs and connect the oxygen supply before dumping cabin pressure and opening the crew door.  That process would have been even more difficult on an aircraft that was in a continuous Dutch roll.

It's also worth noting that the crew's window for action was extremely limited.  The entire flight lasted 11 minutes; as the rolling increased, so did pressure on the tanker's tail section.  When it separated from the rest of the airframe--putting the jet into a steep dive--bail-out would have been impossible, even for crew members who were wearing parachutes.       

The real culprits in the Kyrgyzstan crash (as described in the Time article) were crew training and experience.  At the time of the crash, Captain Voss had been an aircraft commander for less than two months; the co-pilot, Captain Pickney, had recently returned to flying duty after the birth of her first child.  TSgt Mackey had over 3,000 hours in the KC-135, but had spent four years in a non-flying job before re qualifying as a boom operator.  Why was such a relatively inexperienced crew flying together?  Was it a matter of scheduling, or is there a lack of experience among KC-135 crews?  So far, the Air Force hasn't answered those questions, at least publicly.  

Making matters worse, KC-135 crews receive no training in dealing with potential dutch roll problems.  Prior to the Kyrgyzstan disaster, KC-135 simulators were not programmed to give pilots that type of scenario, and practicing that maneuver in actual flight was forbidden.  The accident investigation board also determined that procedural information in the tanker's flight manuals was poorly organized, compounding the difficulty in diagnosing--and correcting--the flight control problem. 

As Mr. Thompson reports, the Air Force has made changes in the wake of last year's crash, but there are no plans to put parachutes back on KC-135s.  And that's probably the right choice.  The crew of Shell 77 were the first to lose their lives since the chutes were removed in 2008.  During that period, the 50-year-old Stratotanker fleet has flown thousand of sorties, transferred millions of pounds of fuel to receiver aircraft around the world, and there was no need for parachutes, until that brief, terrible moment over Kyrgyzstan last spring.  And given the circumstances that led to the crash, there is no clear evidence that the crew would been able to bail out, even if parachutes had been aboard. 

In an era when a single aircraft often costs more than $100 million, safety devices--like parachutes--seem like a very cheap investment.  But life support items must be continuously inspected and repaired, a process that requires significant manpower.  Would you rather have more life support technicians checking and fixing parachutes on KC-135s (that almost certainly will not be used), or working on platforms where ejection or bailing out is much more likely? 

That's the reality that drives the hard choices like the one made back in 2008.  There wasn't a single military leader involved in that decision who didn't understand that someday--under various flight scenarios--a tanker crew might face a bail-out situation.  It was a decision driven by the numbers, ranging from life support personnel costs to the odds of a KC-135 crew having to use their parachutes.  The resulting calculus determined that taking the chutes off the tankers was an acceptable risk. 

Obviously, it was an imperfect decision, but facing the same set of numbers, it's a choice the Air Force would likely make again.  That doesn't mitigate the loss of three brave airmen, and the suffering their families still endure.  It's the harsh reality of military aviation in the days of aging aircraft and limited resources.
ADDENDUM:  As a former aircrew member, this issue is personal.  My crew experience was aboard an Air Force platform that had parachutes, but as we used to joke, they were there to provide some sort of psychological assurance, rather than save our lives.  Our mission crew worked in a computerized capsule in the back of a specially-modified C-130.  With a full crew (including Army liaisons) you could have up to 15 people in a relatively small space.  Bailing out was a veritable kabuki dance that involved (a) Getting out of your seat; (b) Donning your chutes and helmets, and connecting your oxygen supply; (c) lining up in the narrow aisle between the consoles; (d) de-pressurizing the aircraft; (e) opening the capsule door, (f) opening the paratroop door, and (g) bailing out.  By the time that process was complete, we reasoned, the plane would either crash, or we could make an emergency landing. 

Additionally, jumping out of a Herk is a lot easier than a KC-135/707 airframe.  If you depart through the tanker's crew door (near the cockpit), there's a chance you'll hit the wing, get sucked into one of the inboard engines, or bounce along the bottom of the aircraft at better than 300 kts.  A better choice would be the over-wing hatches or the hatch just forward of the boom compartment (on the right side of the aircraft).  But getting to those locations means leaving the cockpit which may be difficult in an emergency. 

Finally, Mr. Thompson didn't provide the full details of that 1969 tanker bail-out over Michigan.  On a message board for the 46th Air Refueling Squadron, Joe Heywood, the navigator involved in that episode, provides a much better account of what prompted four members of the crew to leave the aircraft.  Call it gross buffoonery by an instructor pilot, and read the rest for yourself.  Apparently, the bail out removed just enough human weight for the KC-135 to land just short of the runway, with surprisingly little damage.  Mr. Heywood's jump took place at very low altitude, and the crew was directed to prepare for bailout.  So they were in position and ready to go--very different circumstances from those over Kyrgyzstan last May.  In case you're wondering, Heywood and his comrades represent four of only six people who have successfully bailed out of a KC-135. 

At last report, the famous "gliding pig" of the tanker fleet, tail number 61-0313, was still in service, with the 916th Air Refueling Wing at Seymour Johnson AFB, North Carolina.                                                

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