Significant problem found with F-18/E-18 environmental system

In 2006, the rate of F-18 pilots suffering physiological effects related to the aircraft stood at 3.66 per 100,000 flight hours. In 2009 that began to rise. The rate for the Growler stood at 5.52 from 2010-2011.

From November 1, 2014-October 31, 2015 that rate stood at 28.23 per 100,000 for the Hornet, and 43.57 per 100,000 for the Growler. Symptoms shown by pilots include symptoms related to depressurization, tissue hypoxia and contaminant intoxication. No cause has been found to date as to why the rate is climbing.

Of the 273 cases adjudicated so far by the investigation team, 93 involved some form of contamination, 90 involved an environmental control systems (ECS) component failure, 67 involved human factors, 41 involved an on-board oxygen generating system (OBOGS) component failure, 11 involved a breathing gas delivery component failure, and 45 were inconclusive or involved another system failure.

thehill.com...

I consider this an even bigger deal than the issues with the F-22 OBOGS.

A lot more of these flying sorties than the raptor.

a reply to: Theprimevoyager

This is much bigger than that. There are over 300 Hornets in US service, and over 500 Super Hornets worldwide. This makes the F-22 problem look minor with those rate numbers.

a reply to: Zaphod58

The causes seem varied, with the sort rate of the 18's could it be just increased failures with increased numbers, or do they think it is something more substantial?

a reply to: Bfirez

Right now they're poking in the dark. Some of the flights there are obvious problems, others they fine tooth and nothing is there. This is going to be harder to track down than the F-22 issue.

Shades of issues a decade ago with maintenance on the Pig...
F111 tank reseal health issues.

What's the chances they'll place limitations on how the hornets can be flown? Could have a massive affect for a number of 1 type fleet operators.

a reply to: Donkey09

I don't see how they can. Going to a single type fleet really screwed them.

a reply to: Zaphod58

And that problem is only going to be compounded once the 22's, & 35's are your mainstay. Hears to everyone getting their own airframe in Gen 6!

And it's clearly system related. We had no such problems when breathing straight O2 from the green tanks. I love OBOGS, but it's intergrated into the aircraft and scrubs O2 through that nitrogen / argon process, which just begs the question as to what failure modes are present and how would they affect the pilot.

Not sure if they can test/replicate the conditions occurring at altitude with these jets, but it's really scary, especially in single-pilot operations.

And 100% O2 was the bomb!

a reply to: cosmania

Whatever the ultimate cause it's recent. Ten years ago it was almost unheard of.

Fleet wide, from November 2013-October 2014 it stood at 70.98 per 100,000. The problems vary from type to type. The problem isn't low oxygen levels, but the ability to process the oxygen.

The F-18A-D is seeing more ECS problems. The E/F is seeing OBOGS problems, but they don't know why. The Growler, which tends to fly a higher, straight and level flight path, is seeing a particular valve freeze. That valve is related to cockpit oxygen and avionics cooling.

They've made 18 changes to date, from more frequent testing instead of fly to failure on the legacy aircraft, to a new sieve and scrubber for the OBOGS system. The sieve used was the finest available. In 1982.

m.aviationweek.com...

A Congressional panel is calling for an independent investigation, led by the Navy into the OBOGS problems being seen by the pilots.

Navy and Marine Corps strike fighter aviators face a dangerous loss of air flow while flying. They're set to suffer more than 100 of these hazardous and potentially fatal incidents this year for the second time; one Navy F/A-18 Hornet squadron reported two in a week.

Now, Congress is moving to demand an independent review of the breathing air and decompression problems plaguing the F/A-18 Hornet and EA-18G Growler fleets, which stem from complex air flow systems the Navy has spent years trying to repair.

The congresswoman who made the problem public in February, Rep. Niki Tsongas, D-Mass., is calling for Navy Secretary Ray Mabus to choose a senior official in his office to review the Navy and Marine Corps' efforts to fix the problems and to consult technical and medical experts from outside the Defense Department.

www.navytimes.com...

The FY17 budget calls on the Secretary of the Navy to conduct an engineering and cost analysis involved in putting an Automatic Backup Oxygen System into the F-18 fleet no later than March 15, 2017.

a reply to: Zaphod58

OMG. That can't be cheap, light or easy. Zow.

a reply to: cosmania

No, it won't be, but the incident rate has skyrocketed recently, and really needs fixing. There has to be something inherent in the OBOGS causing it.

Downrange crews are taking extraordinary steps to try to prevent problems with the environmental systems. Both the George Bush and Carl Vinson deployed with hyperbaric chambers on board. The Bush, which is in the Middle East, has had to use its chamber twice already. The first time was when a Growler crew experienced a problem with their environmental system, the second was when a single seat Hornet pilot became disoriented after takeoff. Both aircraft landed safely, and the pilots recovered after treatment in the chamber.

To help prevent the problem, crews are resorting to some unique solutions, approved by their chain of command, up to the three star level. Crews have resorted to DIY solutions, including slam sticks and Garmin watches. The slam sticks monitor cockpit air pressure, and other parameters and include diagnostics, which are analyzed after the flight.

The other solution is the Garmin watch. Several crew members had a watch that have altimeters on them. The idea was pitched up the chain of command, and now the crews are flying with them. They have altimeters and barometric sensors in them, and are set to sound an alarm when certain parameters are reached, to warn the crews.

Fighter and attack squadrons on two U.S. aircraft carriers — one engaged in operations against ISIS, the other on station in the restive West Pacific — have resorted to extraordinary measures to keep their pilots safe from persistent oxygen-supply problems in the Navy’s go-to carrier aircraft, the F-18 Hornet.

Aboard the USS George H.W. Bush in the Persian Gulf, Military.com’s Hope Hedge-Seck reports that the Bush and USS Carl Vinson both deployed in January with hyperbaric chambers, “slam sticks,” and even store-bought Garmin wristwatches to ward off the widespread oxygen problems which have plagued the fleet’s jet trainer aircraft, the F/A-18E and F Super Hornet variants, and the related E/A-18 Growler electronic warfare aircraft.

The Bush has already had to use its hyperbaric chamber twice to treat pilots “who experience[d] hypoxia-like symptoms in the cockpit,” reports Seck: once in February, when a two-person Growler crew experienced “an ‘abnormality’ with the aircraft’s environmental control system,” and again in April, when a solo F/A-18 pilot became disoriented shortly after takeoff.

taskandpurpose.com...

Aviation Week & Space Technology Frozen F/A-18 Valve Is Latest Clue In U.S. Navy’s Hypoxia Mystery

Well that a bit more refreshing than the usual deny deny deny.... pilot error we usually get

a reply to: FredT

This is one if those "eh, maybe" things. I can see how they missed it, if it froze at altitude, but I find it hard to believe that no one caught it at any point until now. The physical O2 system is usually pretty bulletproof as far as valves and hoses go.

Two F-18Es operating off the Truman, belonging to VFA-136, diverted to Incirlik Air Base, Turkey, after a mission over Syria. The diversion occurred due to an oxygen system warning in one of the aircraft. Once on the ground the other aircraft declared an emergency due to hypoxia like symptoms. One of the pilots needed assistance to get out of the aircraft.

www.thedrive.com...