Estimate How Long Philadelphia's Airport Needs to Recover From a One-Day Closure
Company: Google
Role: Product Manager
Category: Product / Decision Making
Difficulty: medium
Interview Round: Other
Philadelphia International Airport is fully shut down for 24 hours: no flights take off or land. After it reopens, how long will it take until the airport is running normally again? Build your answer from explicit numerical estimates and stated assumptions, and explain what determines the recovery time.
```hint Look past the reopening
Getting the runways working again is quick. Work out what piles up while the airport is closed, and what limits how fast that pile can be worked off once flights resume.
```
### Clarifying Questions
- What caused the closure, and was it announced ahead of time so airlines could cancel flights and keep aircraft and crews in position, or was it sudden?
- What counts as normal: flights departing on schedule again, or every stranded traveler and bag reaching its destination?
- When does it happen: an ordinary weekday in a quiet month, or a holiday peak when flights are nearly full?
- Is only this airport affected, or is the wider region disrupted as well, for example by a storm across the Northeast?
### What a Strong Answer Covers
- A definition of "back to normal" that separates the airfield, the airline schedule and the backlog of stranded travelers.
- Round-number estimates of daily flights, seats and passengers that are labeled as assumptions and consistent with one another.
- A recovery model that links the clearing time to the size of the backlog and the spare capacity available each day.
- Sensitivity to the inputs that matter most, such as season, cause and the share of travelers who give up or switch to other options, ending with a range.
- Concrete levers that would shorten the recovery, with their costs and trade-offs.
### Follow-up Questions
- How does your estimate change if the closure happens two days before Thanksgiving?
- The airport is a connecting hub for a large airline. How does a one-day closure ripple through the rest of that airline's network?
- If you were the product manager for an airline's rebooking tools, which real-time metric would tell you the recovery is on track?
Overview: An estimation question for product manager interviews: if Philadelphia's main airport closed for a full day, how long would it take to return to normal operations? It tests defining what normal means, estimating flights, seats and passengers from explicit assumptions, and reasoning about how quickly stranded travelers can be re-accommodated.