import { Tip, Warning, Info, ProTip } from "@/components/mdx"

Dear Passengers Aircraft Management: Complete Systems Guide

The aircraft in Dear Passengers is not a simple vehicle with a throttle and a steering wheel. It is a deeply simulated machine with interconnected systems that each require monitoring, understanding, and active management throughout every phase of flight. The difference between a player who completes flights and a player who masters them comes down to systems knowledge. This guide covers every major aircraft system in detail: how each one works, what the instruments are actually telling you, common failure modes, and the maintenance habits that keep you ahead of problems rather than reacting to them.

Engine Systems

How the Engines Work

Dear Passengers models turbofan engines with impressive fidelity. Each engine has a multi-stage compressor, a combustion chamber, a multi-stage turbine, and an exhaust nozzle. The key parameters you monitor are:

• N1 (Fan Speed): The rotational speed of the low-pressure compressor and fan, expressed as a percentage of maximum. This is your primary thrust indicator. During takeoff, N1 typically sits near 100 percent. At cruise, it settles between 75 and 90 percent depending on altitude and weight.
• N2 (Core Speed): The rotational speed of the high-pressure compressor. N2 drives the accessory gearbox that powers generators, hydraulic pumps, and fuel pumps. If N2 drops below a minimum threshold, you lose electrical and hydraulic power from that engine.
• EGT (Exhaust Gas Temperature): The temperature of gases leaving the turbine section. EGT is your most important engine health parameter. Every degree above normal operating range accelerates wear. Prolonged over-temperature operation will destroy an engine.
• Oil Pressure and Temperature: Lubrication system health. Low oil pressure with normal temperature suggests a leak. High oil temperature with normal pressure suggests a cooling issue. Both demand attention.
• Fuel Flow: The rate of fuel consumption per engine, typically displayed in kilograms or pounds per hour. Useful for cross-checking against your flight plan fuel calculations.
• Vibration: Measured in mils, this indicates engine balance. A sudden increase in vibration often signals foreign object damage or a failing bearing.

Common Engine Failures

Engine failures in Dear Passengers follow realistic patterns. Here are the most frequent scenarios and their signatures:

Compressor Stall: A loud bang, sharp N1 fluctuation, and EGT spike. Caused by disrupted airflow through the compressor -- often from rapid throttle movement, extreme angle of attack, or foreign object ingestion. Immediately retard the affected throttle and allow airflow to stabilize before slowly advancing power again.

Oil System Failure: Gradual oil pressure decline over several minutes, followed by rising oil temperature. If oil pressure drops below minimums, you must shut down the engine before it seizes. A seized engine cannot be restarted and may cause airframe damage from vibration.

Engine Fire: Indicated by a fire warning light, high EGT, and potential smoke in the cabin or cockpit. Execute the engine fire checklist immediately: throttle to idle, fire handle pulled, fire bottle discharged. If the fire persists after the first bottle, discharge the second. If it still persists, land as soon as possible.

Controlled Engine Failure: Sometimes you choose to shut down an engine proactively -- low oil pressure, persistent vibration, or a precautionary shutdown after a compressor stall that will not stabilize. A controlled shutdown is always preferable to an uncontrolled failure.

<Warning> Never shut down an engine without positively identifying it. The number of virtual passengers who have perished because a player shut down the good engine while the bad one kept burning is staggering. Point at the gauge. Say the engine number out loud. Have your co-op partner confirm. Then act. </Warning>

Engine Maintenance

Between flights, each engine shows a wear percentage and a condition report. Prioritize maintenance based on:

• Wear above 70 percent: Schedule maintenance within the next three flights.
• Wear above 85 percent: Maintain before next flight. Risk of random failure increases sharply beyond this point.
• Any abnormal parameter trend: Even if wear is low, an EGT that has been creeping upward over the last three flights deserves investigation.

Engine overhauls are expensive but necessary. A $15,000 overhaul is cheaper than an engine failure at V1 with 200 passengers behind you.

Fuel System

Fuel Storage and Management

The fuel system comprises multiple tanks -- typically left wing, right wing, and center tank on larger aircraft. Fuel is consumed from the center tank first, then from the wing tanks. This sequence maintains wing bending relief (fuel weight in the wings counteracts lift forces that bend the wings upward).

Key fuel parameters:

• Total Fuel Quantity: The big number. Compare against flight plan estimates at every waypoint.
• Tank Distribution: Left vs. right wing imbalance. A difference of more than a few hundred pounds causes a roll tendency that the autopilot or trim must correct. Extreme imbalance affects handling during manual flight.
• Fuel Temperature: Jet fuel can wax at extremely low temperatures (below approximately -40 degrees C), which clogs filters and starves engines. High-altitude, cold-weather flights require fuel temperature monitoring.
• Fuel Used vs. Planned: The flight plan screen shows planned fuel burn for each segment. If actual burn exceeds planned by more than 5 percent, investigate. Common causes: stronger headwinds than forecast, cruising below optimal altitude, or an engine running inefficiently.

Fuel Planning Rules

The flight planning tool calculates a minimum fuel load based on the route, aircraft type, and forecast winds. You can add contingency fuel. Always add contingency fuel. The minimum assumptions assume everything goes perfectly, which it never does.

A practical fuel planning framework:

• Trip fuel: What the plan says you need from takeoff to landing.
• Contingency fuel (5-10 percent of trip): For minor deviations, holding, and unexpected headwinds.
• Alternate fuel: Fuel to fly from your destination to your filed alternate airport, plus an approach.
• Final reserve: Fuel for 30 minutes of holding at 1,500 feet above the alternate.

On a short regional flight, the absolute numbers are small, and you may feel like you are carrying too much. You are not. The one flight where you need every pound of that contingency fuel will justify every flight where you did not.

<ProTip> Pro Tip: During cruise, check your fuel state against the flight plan at least every 30 minutes. If you notice a developing deficit, you have options: adjust altitude for better efficiency, request a more direct routing from ATC, or begin planning a tech stop for fuel. Catching a deficit early gives you options. Catching it on descent gives you an emergency. </ProTip>

Electrical System

Power Architecture

The electrical system follows a layered architecture:

• Primary power: Engine-driven generators (one per engine). Each generator can power the entire aircraft. Two engines means full redundancy.
• Auxiliary power: The APU generator. Available on the ground and, on most aircraft, in flight below a certain altitude (typically 25,000 feet for in-flight APU starts). If you lose an engine generator, the APU can replace it.
• Battery power: Provides 30-60 minutes of power for essential instruments only. No cabin lighting, no galley power, no non-essential avionics. If you are on battery power, you are landing at the nearest airport, now.
• Emergency power: A subset of battery power for the absolute minimum instruments: attitude indicator, airspeed, altimeter, and one radio. Typically lasts 30 minutes.

Load Shedding

When electrical capacity is reduced -- for example, after losing one engine generator and being unable to start the APU -- you must shed non-essential electrical loads to keep critical systems powered. The load shedding priority from first to shed to last to shed:

1. Galley power (ovens, coffee makers, cabin entertainment)
2. Cabin lighting (reduce to minimum safe level)
3. Redundant navigation systems
4. Weather radar
5. Non-essential cockpit displays
6. Critical flight instruments (never shed these)

The systems panel shows current electrical load and capacity. Keep load below 90 percent of available capacity to leave margin for transients. When shedding load, shed in chunks and verify the load reduction after each step.

Cabin Pressure and Environmental Control

How Pressurization Works

At cruise altitude (typically 30,000 to 40,000 feet), the outside air pressure is too low for human survival. The cabin pressure system uses bleed air from the engines (compressed air tapped from the compressor section) to maintain a cabin altitude of approximately 6,000 to 8,000 feet regardless of the aircraft's actual altitude.

Key pressure parameters:

• Cabin Altitude: The effective altitude inside the cabin. Should stay below 8,000 feet during cruise. Above 10,000 feet triggers an amber alert. Above 14,000 feet triggers a master warning and automatic oxygen mask deployment.
• Cabin Rate of Climb/Descent: How fast cabin altitude is changing. Normal is 300-500 feet per minute. Anything above 1,000 feet per minute is uncomfortable. Anything above 2,000 is an emergency.
• Differential Pressure: The difference between cabin pressure and outside pressure, measured in PSI. Each aircraft has a maximum differential -- typically 8-9 PSI for regional jets, up to 9.4 PSI for wide-bodies. Exceeding this limit can damage the fuselage.

Depressurization Response

A loss of cabin pressure at altitude is one of the most time-critical emergencies in aviation. The sequence:

1. Don oxygen masks immediately (crew first, you cannot help passengers if you are unconscious).
2. Initiate emergency descent: Throttles to idle, speed brakes extended, descend at maximum safe speed to 10,000 feet (or the minimum safe altitude for terrain, whichever is higher).
3. Verify passenger oxygen masks have deployed: These deploy automatically when cabin altitude exceeds 14,000 feet, but verify.
4. Declare emergency to ATC: State the nature of the emergency and your intentions.

At 35,000 feet, time of useful consciousness without supplemental oxygen is approximately 30 to 60 seconds. You have less than a minute to get your mask on and start descending. Do not wait.

Cabin Temperature

Separate from pressure, the environmental control system manages cabin temperature. This seems simple but has nuance:

• Different zones heat and cool at different rates. The forward cabin near the cockpit may be warmer. Window seats in direct sunlight heat up faster.
• A full cabin generates significant body heat. An empty cabin cools faster.
• The galley ovens produce substantial heat. If meals are being prepared, expect the cabin temperature to rise.
• Rapid temperature changes cause more complaints than a consistent temperature that is slightly off the ideal setpoint. Aim for stability.

Hydraulic System

What Hydraulics Power

The hydraulic system provides the mechanical force for high-load aircraft systems:

• Flight controls: Ailerons, elevators, rudder -- the surfaces that control the aircraft. Without hydraulics, these surfaces are extremely difficult or impossible to move at high speeds.
• Landing gear: Extension and retraction. Without hydraulics, gear must be extended using the manual/gravity extension procedure, which is slow and unrecoverable (you cannot retract the gear again).
• Flaps and slats: High-lift devices for takeoff and landing.
• Wheel brakes: Stopping a 150,000-pound aircraft without hydraulic brakes is not possible on most runways.
• Nosewheel steering: Ground maneuvering capability.

Most aircraft have two or three independent hydraulic systems for redundancy. A failure of one system is manageable. A failure of two systems is an emergency. A failure of all systems means you will land without flight controls, flaps, or brakes -- and you will not walk away from it.

Hydraulic Monitoring

The hydraulic system display shows:

• System pressure: Normally around 3,000 PSI. Low pressure indicates a leak or pump failure.
• Fluid quantity: Declining quantity confirms a leak. A leak that continues after the pump is isolated means the leak is in the reservoir or lines.
• Pump status: Each system has at least one engine-driven pump and often an electric backup pump.

<Info> Hydraulic failures are progressive in Dear Passengers. A slow leak will gradually reduce fluid quantity and pressure over several minutes, giving you warning. A catastrophic line rupture causes near-instant pressure loss. The difference in response is significant -- a slow leak may let you reach your destination; a rupture demands immediate diversion. </Info>

Navigation Systems

Flight Management System (FMS)

The FMS is the brain of the navigation system. It holds your flight plan, calculates performance data, and interfaces with the autopilot. Key FMS pages:

• Route page: All waypoints from origin to destination, with distances, headings, and altitude constraints.
• Performance page: Current speeds, fuel flow, weight, and optimal altitude calculations.
• Progress page: Distance and time to destination, next waypoint, and fuel remaining at each point.
• Navigation radios page: Tuning for VOR, DME, and ILS frequencies.

Navigation Displays

The primary navigation display (ND) shows a map view with your route, waypoints, nearby airports, and weather radar overlay. Modes:

• Map mode: The standard view, showing your route and surrounding geography.
• Plan mode: Shows the entire route at once, useful for reviewing the big picture.
• Approach mode: Zooms in on the approach segment, showing the ILS or RNAV approach path.
• VOR mode: A raw radio navigation display showing bearing and distance to a tuned VOR station.

Autopilot Modes

The autopilot can control various aspects of flight depending on mode:

• LNAV (Lateral Navigation): Follows the programmed route laterally. Reliable for the entire flight.
• VNAV (Vertical Navigation): Follows the programmed altitude profile. Requires careful monitoring during climb and descent -- VNAV can command aggressive pitch changes if the altitude constraints are tight.
• ALT HOLD: Maintains current altitude. Simple and reliable.
• HDG SEL: Follows a selected heading rather than the programmed route. Used for ATC vectors and weather deviations.
• Approach mode: Captures and tracks an ILS or RNAV approach path for landing.

<ProTip> Pro Tip: Use autopilot during cruise to reduce workload, but hand-fly the first two minutes after takeoff and the last five minutes before landing. This keeps your manual flying skills sharp for the moments when the autopilot cannot help you -- like an emergency where automation is unavailable. </ProTip>

Communications Systems

Radio Setup

Your aircraft has multiple radios, typically:

• VHF 1: Primary ATC communication. Set to the current controller's frequency.
• VHF 2: Backup ATC or company frequency. Often set to the next expected frequency in advance (guard frequency 121.5 as a backup).
• Intercom: Cockpit-to-cabin communication. Used for crew coordination and passenger announcements.

ATC Communication Flow

ATC communication follows a predictable rhythm in Dear Passengers:

1. Clearance delivery: Receive your IFR clearance before pushback.
2. Ground: Taxi instructions from gate to runway.
3. Tower: Takeoff and landing clearance.
4. Departure/Approach: Radar vectors during climb-out and approach.
5. Center (En-route): Cruise phase management, handoffs between sectors.

The AI co-pilot handles routine ATC calls well if you delegate radio duties. You should take over the radio for non-standard communications: emergency declarations, weather deviations, or negotiating direct routings.

Maintenance Strategy: A System-Level Approach

Managing all these systems across multiple flights requires a maintenance strategy. Here is a framework that works:

Pre-Flight Verification

Before every flight, check:

• Engine wear and trend data
• Hydraulic fluid levels
• APU serviceability
• Oxygen system quantity
• Any deferred maintenance items from previous flights

Scheduled Maintenance Rhythm

• Every flight: Address any red-zone wear items.
• Every 3 flights: Full systems inspection. Address all yellow-zone items.
• Every 10 flights: Major service. Overhaul items approaching their recommended service intervals, even if not yet in the red.

Cost Management

Maintenance is expensive, but emergencies are more expensive. A flight that diverts for an engine shutdown costs far more in lost revenue, reputation damage, and post-incident repairs than the maintenance that would have prevented it. Run the numbers once, and the calculus is clear: spend on maintenance.

Bringing It All Together

The aircraft systems in Dear Passengers are not independent. Engine condition affects electrical generation. Electrical failures cascade into navigation and communication losses. Hydraulic problems affect flight controls and landing capability. The mark of an expert player is not knowing each system in isolation -- it is understanding how they connect and managing them as a unified whole.

Start with engines and fuel. Master those. Add electrical and hydraulics. Then dive into the nuances of pressurization and environmental control. Build your systems knowledge incrementally, and each new layer will make you a more capable captain.

For more on handling the emergencies that result from system failures, see our emergency situations guide. For fundamentals, the beginner guide is a good place to start.