Tenerife was not a failure to communicate. It was a failure to establish that everyone was acting from the same understanding.
Communication can exist without alignment
Every organisation believes it communicates. Meetings are held, emails are sent, dashboards are reviewed, updates are delivered and instructions move through formal reporting lines.
Yet projects still stall because people leave the same meeting with different interpretations of what was decided. Senior leaders believe an instruction was clear. Managers believe they were given discretion. Operational teams believe approval is still required.
Everyone has communicated, but the organisation has not established shared understanding.
The Tenerife airport disaster remains one of history’s most devastating examples of this gap.
On 27 March 1977, KLM Flight 4805 and Pan Am Flight 1736 collided on the runway at Los Rodeos Airport on the island of Tenerife. A total of 583 people were killed, making it the deadliest accident in commercial aviation history.
Neither aircraft had originally intended to land there. A bombing and subsequent threat at Gran Canaria Airport diverted multiple flights to the smaller Los Rodeos facility. The airport became congested, parked aircraft obstructed normal taxi routes, visibility deteriorated in moving fog, and both Boeing 747s were required to use the runway for taxiing.
The operating environment had become heavier before either aircraft began its final movement.
The disaster did not begin with one final decision. It developed as an overloaded system allowed different assumptions to become operational reality.
The system was carrying more load than usual
Los Rodeos was operating outside its normal rhythm. Diverted aircraft crowded the airport. The usual taxiway was obstructed. Controllers and crews were working within an unfamiliar arrangement. The weather reduced visibility until the control tower could not see the aircraft and the crews could not see one another.
None of those conditions alone explains the collision. Together, they increased the cognitive and operational load placed on every person in the system.
Pilots had to interpret taxi instructions while identifying poorly marked exits in low visibility. Air traffic control had to coordinate multiple aircraft without ground radar. Crews were managing delays, schedules, duty-time considerations, passenger needs, fuel and deteriorating weather.
This is how pressure often develops inside organisations. The system does not suddenly stop working. Instead, ordinary tasks require more interpretation, more coordination and more individual judgement than they normally would.
- Temporary arrangements become the operating model.
- Teams work around unavailable systems.
- Decision-makers carry more variables than usual.
- Established pathways become congested.
- People rely increasingly on assumptions to maintain momentum.
Performance may still appear normal, but the margin for misunderstanding has narrowed.
Leadership load rises when the environment demands more interpretation than the system is designed to support.
Six dimensions of Leadership Under Load revealed by Tenerife
Operational overload
Diversions, congestion, fog and altered taxi arrangements increased pressure across the airport before the final decisions were made.
Ambiguous language
Radio exchanges occurred, but wording and overlapping transmissions did not produce one unmistakable shared understanding.
Assumption substitution
Participants acted from what they believed others meant rather than from fully verified conditions.
Authority gradient
The influence of a highly senior captain shaped how uncertainty and challenge were handled inside the cockpit.
Reduced challenge
Concerns were raised, but they did not interrupt the developing course of action with enough force to stop it.
Fragmented realities
The tower, KLM crew and Pan Am crew did not all hold the same mental picture of the runway at the same time.
Communication is not the same as shared understanding
It would be inaccurate to say that people stopped communicating. The air traffic controller was speaking with both aircraft. The flight crews were communicating within their cockpits. Instructions, acknowledgements and concerns were exchanged.
The failure was more subtle.
The KLM crew believed their position and clearance supported beginning take-off. The control tower believed the KLM aircraft was waiting. The Pan Am aircraft was still taxiing on the runway and had not yet reported clear.
Everyone was participating in the same communication network while carrying a different version of the operational reality.
This occurs constantly inside organisations. A leadership team says a project has been approved, while finance believes further validation is required. An executive says a manager owns the decision, while the manager believes the executive expects to review it. A board believes a risk has been controlled because it was discussed, while the operational team believes it merely reported the risk.
The existence of communication creates confidence that alignment exists. That confidence can make the gap harder to detect.
Communication becomes dangerous when the fact that people have spoken is mistaken for proof that they understand one another.
Assumptions remove the need to ask another question
Assumptions are not inherently irrational. Organisations could not function if every ordinary action required complete verification from first principles.
The risk emerges when assumptions remain invisible while conditions are changing.
Under pressure, people use familiar patterns to fill gaps in incomplete information. They interpret an ambiguous statement according to what they expect it to mean. They hear confirmation because they are ready to proceed. They assume another team has completed an action because the workflow normally requires it.
Assumption allows activity to continue, but it also reduces curiosity.
Once someone believes they understand the situation, asking another question can feel unnecessary, slow or even obstructive. In a hierarchical environment, it may also feel like a challenge to the competence of the person who appears certain.
This is why assumptions become particularly dangerous when confidence and authority are combined.
Assumptions are dangerous not only because they may be wrong, but because they remove the perceived need to verify them.
Authority changes how information is heard
The KLM captain was highly experienced and held significant professional standing. He was also a senior training captain responsible for instructing and assessing other pilots.
Experience itself was not the problem. Organisations need experienced people to exercise judgement, particularly under pressure.
The structural risk was that seniority affected the weight given to uncertainty.
Inside the KLM cockpit, questions were raised about clearance and whether the Pan Am aircraft had left the runway. Those questions did not produce a decisive interruption to the take-off roll.
In organisations, authority changes communication long before anyone explicitly silences another person. People soften language. They turn warnings into suggestions. They seek reassurance rather than state disagreement. They assume a senior leader must possess information they do not.
The leader may hear a tentative question and interpret it as a minor concern. The person raising it may believe they have communicated a serious warning.
Both leave the exchange believing their role has been fulfilled.
Authority does not need to suppress information completely. It only needs to reduce its influence at the moment it matters.
Challenge culture must work before certainty exists
It is easy to support challenge in principle. Many organisations say employees should speak up, question decisions and raise concerns.
The practical test is whether challenge can interrupt momentum before the challenger has complete proof.
By the time certainty exists, the decision may already have been executed. Effective challenge culture therefore allows someone to say:
- “I do not think we share the same understanding.”
- “I need us to stop until this is confirmed.”
- “The available information does not support proceeding.”
- “I may be wrong, but the consequence requires verification.”
This is more demanding than encouraging people to contribute ideas. It requires leaders to make interruption legitimate, especially when time pressure, confidence and status are all pushing towards action.
A healthy challenge culture does not remove accountability from the leader. It improves the information available to that leader before accountability is exercised.
Speaking up is not enough if the system does not give challenge the power to pause action.
Pressure rewards confidence when the system should reward confirmation
Under pressure, confidence is efficient. It reduces debate, provides direction and allows people to move. This is why decisive leaders are often valued during uncertainty.
Yet confidence can become dangerous when it substitutes for confirmation.
A leader who appears certain can unintentionally close the space in which others might question the underlying assumptions. Teams begin interpreting confidence as evidence. The organisation stops checking whether the certainty is supported by a shared operational picture.
Verification may then be dismissed as hesitation, bureaucracy or lack of trust.
Strong organisations make a deliberate distinction between decisions that require speed and conditions that require confirmation. They recognise that a brief pause to verify a critical assumption may protect the speed and effectiveness of everything that follows.
Healthy organisations do not reward confidence alone. They reward the discipline to confirm what confidence is built upon.
Standard language reduces interpretation load
One of aviation’s enduring responses to accidents involving communication has been the continued strengthening of standard phraseology, read-backs and explicit confirmation.
Standardisation is sometimes criticised in organisations as rigid or bureaucratic. Used poorly, it can become both. Used well, it reduces the amount of interpretation required when consequences are high.
Clear language matters because ordinary words can carry different operational meanings to different people. Terms such as approved, endorsed, noted, reviewed, supported, complete and ready are frequently used as though their meaning is universal.
It rarely is.
Does “approved” mean the work can begin, or only that funding can be sought? Does “reviewed” mean someone checked the document, accepted the risk or merely received it? Does “the team owns this” include authority to decide, or only responsibility to prepare a recommendation?
The more consequential the decision, the less an organisation should rely on language whose meaning changes with context or hierarchy.
Standard language is not needed because people lack intelligence. It is needed because intelligent people interpret ambiguity differently under pressure.
Read-back is an organisational discipline
A read-back requires the receiver to restate the instruction or decision so the sender can confirm that the intended meaning has been understood.
Many organisations rely instead on passive acknowledgement:
- “Understood.”
- “Noted.”
- “Sounds good.”
- “We are aligned.”
- “Leave it with us.”
These responses confirm receipt. They do not confirm interpretation.
An organisational read-back may sound like:
- “To confirm, we can proceed without returning for further approval.”
- “The decision owner is the regional manager, and the executive is informed rather than approving.”
- “The risk has been accepted until 30 September, after which the control must be reviewed.”
- “Success means service continuity, even if the original delivery date moves.”
These statements may feel repetitive. That repetition exposes differences before they become consequences.
Acknowledgement confirms that words were heard. Read-back confirms what those words now authorise someone to do.
Shared understanding is an operational control
Organisations often treat shared understanding as a cultural aspiration: something created through good relationships, transparent communication and collaborative leadership.
It is also an operational control.
When different teams hold different understandings of authority, status, risk or timing, the organisation is exposed regardless of how frequently people communicate.
Shared understanding requires more than distributing information. It requires active confirmation of:
- what is known
- what remains uncertain
- who holds decision authority
- what action is currently permitted
- what condition must be verified before proceeding
- what signal will confirm completion
This reduces the gap between the formal system and the mental model people use to operate within it.
Organisations do not act on policies and structures alone. They act on what people believe those policies and structures mean in the moment.
What modern leaders should examine
Where do assumptions replace verification?
Identify consequential decisions that proceed because people believe another action, approval or check has already occurred.
Can challenge interrupt momentum?
Test whether a less-senior person can pause an important action without first proving that the senior decision-maker is wrong.
Does authority distort information?
Examine whether warnings become softer, shorter or less influential as they move towards senior leaders.
Does acknowledgement confirm meaning?
Replace passive confirmation with explicit restatement when authority, risk, ownership or completion matters.
Is operational language precise?
Clarify terms such as approved, reviewed, endorsed, complete, ready and owned before teams act on different interpretations.
Do leaders verify their certainty?
Create routines that require important assumptions to be tested even when the most senior person in the room appears confident.
The lesson is not that hierarchy should disappear
Tenerife is sometimes simplified into an argument that hierarchy itself is dangerous.
High-consequence systems still need clear command, defined accountability and decisive leadership. Removing hierarchy would not automatically produce safer or more effective decisions.
The question is whether hierarchy improves the organisation’s use of information or prevents information from influencing the decision.
Healthy authority creates direction while remaining open to correction. It makes accountability visible without requiring the leader to appear infallible. It allows a junior person to introduce uncertainty without treating that uncertainty as disloyalty.
The strongest leaders do not weaken their authority by inviting confirmation. They make their authority more reliable.
Leadership authority becomes safer when people can challenge the decision without challenging the dignity of the leader.
The Leadership Under Load lesson
Tenerife was not caused by one isolated communication error. It emerged from a system under unusual pressure in which congestion, poor visibility, ambiguous language, assumptions and hierarchy interacted.
People communicated. Concerns were expressed. Instructions were transmitted. Yet those interactions did not produce one shared understanding of whether the runway was clear and whether take-off had been authorised.
That is the organisational lesson.
Leadership Under Load is not simply concerned with whether information is present. It asks whether the system allows that information to shape understanding and action, particularly when authority and pressure are already pushing the organisation in one direction.
The most valuable decision may not always be the next decision.
Sometimes it is confirming that everyone is making the same one.
Leadership Under Load asks whether organisations truly share understanding—or merely share confidence that they do.
Where the Leadership Load Diagnostic fits
The Leadership Load Diagnostic helps organisations identify where authority, escalation, unclear decision rights and operational assumptions are creating hidden risk or concentrating pressure around senior leaders.
It examines whether information can retain its influence as it moves upward, whether teams understand what they are authorised to decide and whether leadership systems create confirmation or merely communication activity.
The objective is not to remove hierarchy or slow every decision.
It is to ensure that speed is supported by clarity, challenge remains possible and important decisions are not resting on different versions of reality.
Related Leadership Under Load insights
Frequently asked questions
What happened in the Tenerife airport disaster?
On 27 March 1977, KLM Flight 4805 began its take-off roll at Los Rodeos Airport while Pan Am Flight 1736 was still taxiing on the same runway in dense fog. The two Boeing 747 aircraft collided, killing 583 people.
What caused the Tenerife airport disaster?
The accident involved multiple interacting factors, including airport congestion following diversions, poor visibility, ambiguous and overlapping radio communications, incorrect assumptions about clearance and runway status, and the KLM aircraft beginning take-off without clearance while the Pan Am aircraft remained on the runway.
What does Tenerife teach us about leadership?
Tenerife demonstrates that communication does not automatically create shared understanding. Authority, pressure and assumptions can change how information is interpreted and whether concerns are influential enough to interrupt action.
What is an authority gradient?
An authority gradient describes how differences in status, seniority or power affect communication. A steep authority gradient can make less-senior people reluctant to question, correct or interrupt a senior decision-maker.
What is challenge culture?
Challenge culture is the practical ability for people to question assumptions, raise uncertainty and pause action when consequences require verification, without being punished or dismissed because of their rank.
How can organisations create shared understanding?
Organisations can strengthen shared understanding through precise language, explicit decision rights, read-backs of consequential instructions, visible assumptions, clear stop conditions and leadership behaviour that treats verification as disciplined performance rather than hesitation.
Communication is only complete when understanding is shared.
When pressure rises, authority becomes heavier and assumptions become easier to accept. Resilient organisations create enough clarity and challenge to confirm that everyone is operating from the same reality before action becomes irreversible.