Letters to the Editor
SUBJECT: Helios 737 Crash in Greece
FROM: Ward Massey
The crash of the Helios 737 Airliner in Greece: No pressurization, pilots poorly trained, oxygen masks - on above 10,000 ft. mean sea level (msl). John Nance is not all wrong.
This tragedy (and the Payne Stewart Learjet crash) are a sad reminder of the lack of hypoxia training that civilian trained aircrews receive. The military has had many incidences like these since World War II, but mostly they occurred in single-seat aircraft and the loss of life was minimal. As a result of these experiences the military trained aircrews receive initial and recurrent training to help each individual understand his/her own early hypoxia symptoms and how to take immediate action that will save their lives (and perhaps others on the aircraft).
The initial reports that led to the hypoxia speculation were based on the aircrew's Air Traffic Control (ATC) transmissions and subsequent radio discussions with the airline's maintenance department about a series of alarms that started to go off after passing through 10,000 ft. msl.
When the crew stopped responding to radio calls ATC called for an intercept that was accomplished by two Greek F-16s. The fighters shadowed the airliner while taking pictures and trying to raise the crew on the radio until one of the engines ran out of fuel causing the autopilot to disengage and the plane to ultimately crash.
On September 7, 2005 the International Herald Tribune published an article by DON PHILLIPS that covered the preliminary findings of the accident investigation.
According to the article:
Maintenance had been performed on the aircraft the night before and the pressurization control knob was left in a position that would not allow the plane to pressurize, at all. According to investigators the aircrew failed to correct this during the pre-flight per their checklist.
During climbout while passing through 10,000 ft. msl the cabin altitude alert sounded. This alarm is a horn that is the same one used on the ground to announce that the plane is not properly configured (doors closed, flaps set, etc.) for takeoff. The aircrew was confused by this as they did not remember the dual purpose of the horn (the takeoff function is disabled when the landing gear are no longer touching the ground.)
The plane continued to climb on autopilot and at 14,000 ft. msl the oxygen masks deployed (as designed) to provide supplemental oxygen to the passengers, and another alarm sounded to alert the crew that there was insufficient cooling air in the avionics compartment. The cockpit voice recorder (CVR) revealed that this caused great confusion on the flight deck, which is reasonable to understand, as they were most likely already feeling the effects of hypoxia at that altitude.
According to the article "During this time, the captain and co-pilot discovered that they had no common language and that their English was not good enough for the complicated technical conversation required to fix the problem[s]"
The aircrew called their maintenance people in Cyprus to figure out how to shut off the alarm(s) and were told that the circuit breaker was behind the Captain's seat. "The captain got up from his seat to look for the circuit breaker, apparently ignoring the confused co-pilot."
According to officials "The captain lost consciousness first on the floor of the cockpit, followed by the co-pilot, who remained in his seat."
The plane did what it was told and climbed on course to 34,000 ft. msl (FL 340), flew to the destination waypoint and then entered a holding pattern, where it was intercepted by the Greek fighter planes.
Reportedly, Boeing has issued warnings to all 737 operators to re-emphasize how the various warning systems in the aircraft work and what their specific remedial action is. "The company notice said there had been other instances of confusion over the horn by pilots." No information was given in that article as to what was going on in the cabin.
Since the plane flew for approximately three hours before one of the engines quit, it is safe to say that the passengers were all incapacitate since the cabin's oxygen system capacity is only designed to provide for an emergency descent from cruising altitude to below 10,000 ft. msl. Unconfirmed reports stated that it looked as if one of the flight attendants had entered the flight deck before the plane went down.
Since the official report has not yet been published some of this information may be corrected at a later date.
Of FARs and training:
The CRM issues and aircraft specific training from this crash will be discussed for years to come. I would like to concentrate on two key areas:
Hypoxia Training and High Altitude Flight.
While the Editor is completely correct in his discussion of FAR Sec. 121.333 there is more to the story, and John Nance is not completely wrong. Both men are talking from their aviation experience.
Robert Boser received his training from civilian companies and operators, and John Nance was trained by the military (U.S.A.F). While most of the training these two men received is very similar there are somewhat subtle yet distinct differences between the two. Most notably is the differences in training and the rules military and civilian operators abide by, in regards to supplemental oxygen requirements.
Where the FARs require no actual hypoxia training for operators of civil aircraft, the military requires initial and recurrent training in an "altitude chamber." This training is designed to acquaint aircrew with the dangers of high altitude flying firsthand, and allow them to understand how hypoxia affects them individually.
Where the FARs (91.211) require a pilot to use supplemental oxygen while above 12,500 ft. msl (cabin altitude), but not higher than 14,000 ft. msl, for more than 30 minutes, The Air Force requires that all crewmembers have their oxygen masks on and set to 100% at all times when the cabin altitude is above 10,000 ft. msl. The continuous oxygen requirement per FAR is 14,000 ft. msl. Where the FARs (121.333) use 25,000 ft. msl as the altitude when the remaining pilot on the flight deck must "don the mask", the Air Force uses 35,000 ft. msl for this situation.
The difference is in the training and experience from these two "worlds" which dictates the different requirements by both.
Another area that was involved in these incidences is pressurized and non-pressurized high altitude flight (above 10,000 or 14,000 ft. msl.)
Stay with me in this:
If an aircraft that can be pressurized is not pressurizing it is not pressurized and therefore cannot "lose" pressurization.
This is bound to cause a semantics debate between myself and the editor, but it is a subtle yet possibly fatal distinction. In both of these crashes it is safe to say that neither aircraft pressurized during the climb and therefore FAR 121.333 did not come into play. What did come into play was FAR 91.211.
Why is this important? It has to do with how crewmembers are trained to identify hazards and what must be done to mitigate them. If all of your training regarding pressurization is about "losing" it then you may not be able to identify that you don't "have" it in the first place. If, at the very least one of the pilots of one of these aircraft had recognized that they were hypoxic, they could have saved the aircraft and all aboard. I think that's pretty important.
Editor ASC reply:
That article can be found at:
The problem is that the information in that article is alleged to have come from insider sources of the investigation team, but they are not named so no one can check those sources, to see how accurate the information is. One has to wonder why members of that investigation team would leak to the press, in violation of their own rules, which each is sworn to uphold. All too often the leaker has some private political agenda to advance.
It may turn out that all the information in that article is accurate. Or, that pertinent parts have been left out of that story, by the leaker. We cannot know for now, so while it is interesting to read such press speculations, it is best to wait for the interim and final reports from the official investigating board, before we come to any firm conclusions about the causes (probable and contributing) of that unfortunate crash. I am glad Mr. Massey included this statement, at the end of his discussion of the IHT article:
I think Robert Baron has given the best advice in regards to press speculations, during the course of an accident investigation. At AirlineSafety.Com, we will be happy to provide additional information on that crash, once the source material comes from the official releases, by the accident board conducting that investigation.
Editor ASC reply:
John Nance was trained by both the military and civilian airlines. He was a pilot for both Braniff (he lost that job when Braniff went bankrupt, following the 1978 Airline Deregulation Act---which, in my humble speculation, had a lot to do with why he wrote such an atrocious, purely polemic, union propaganda piece like Blind Trust) and Alaskan Airlines. The comments he made in that ABC News interview, about the Payne Stewart Lear Jet crash, referenced only civilian (airline and private jets) training and regulations, not those of the military.
Editor ASC reply:
I disagree. John Nance was clearly wrong, as to his contention that the other pilot wasn't required to don the oxygen mask, below FL 350, when the other pilot left his seat, and as to his contention that the crew should "...request an emergency descent..." when the plane experiences a sudden loss of pressurization.
Here is what I actually said about Nance, in that Helios editorial:
John Nance did say those things in that ABC News interview (still posted on the Internet, six years later), and it is clear he wasn't referencing military regs or training at all. He was discussing civilian private charter and airline procedures and regulations, in reference to loss of pressurization. Excerpts:
Editor ASC reply:
The first part of this statement is not accurate. FAR Sec. 61.31 - (Type rating requirements, additional training, and authorization requirements), does require some very specific types of hypoxia training for civilian pilots of pressurized aircraft:
While there is an FAR exception for that training, if the applicant has had the type of military training referenced by Mr. Massey, the reality is that Airlines do not segregate their pilots into different training courses, depending on whether they have had the military hypoxia training or not. All their pilots get the same initial and recurrent annual training on the subject of hypoxia, which includes films of hypobaric altitude chamber tests, ground school training on the proper procedures for the normal preflight and operation of the pressurization and supplemental oxygen systems, for their particular aircraft----including the emergency procedures to be followed, in the event of loss of cabin pressurization----and in simulator demonstrations and practice of the "high dive," procedure, which is to be carried out immediately, in the event of loss of cabin pressure. Such training is type specific for each pilot, as to the controls and warning indicators on their specific aircraft.
Editor ASC reply:
If something is wrong with the pressurization system before the plane has left the ground, so that it is not able to pressurize as it climbs, then it has indeed lost its pressurization [capability].
Since the net result will be the same as when the pressurization works initially, but then the system fails either gradually or suddenly (assuming the same scenario----where the pilots fail to follow proper analysis procedures for the problem, and then fail to follow the required immediate action emergency procedures), then I am not sure we have failed to comment properly, about the dangers of hypoxia and of how critically important it is for all pilots to be properly trained about the subject of hypoxia and of the importance of all pilots always adhering to their SOP and FAR requirements, in relation to their aircraft pressurization and supplemental oxygen systems.
Mr. Massey's comment of "If all of your training regarding pressurization is about "losing" it..." is a hypothetical which does not happen in the real world. In the United States, the airlines' training syllabus for all their pilots, on the subject of pressurization, supplemental oxygen, hypoxia, analysis of problems and required emergency procedures, is quite comprehensive and all inclusive.
If it turns out that the pilots in the Helios 737 crash were not properly trained, as to how their aircraft systems operated, and as to how they were supposed to analyze and react to their [apparent] emergency, then there will be a lot said about those deficiencies in training. Usually, if that turns out to be the case, the accident board will make many recommendations about how to ensure such insufficient training never happens again.
I thank Mr. Massey for submitting his letter on this subject. I am always happy to expand the discussion on the important safety issue of hypoxia and how malfunctions of pressurization systems need not result in anything other than a necessary unscheduled landing. That is how it usually works out, where the pilots have had the required training on those subjects and they are willing to strictly adhere to their required SOPs and FARs.
November 13, 2005
Robert J. Boser